82 seca xj750, big rant, looking for help

Ok so first of all I'd like to thank everyone that have been active on this forum because Ive been using it for a while, and even tho I don't post, I get plenty of help from the previous posts.

Now about a year ago, I got my hand on an 82 750seca. The guy that sold it to me bought it from the family of someone that passed away. So it's very hard to get a proper history on the bike.
Seller had intention of restoring it, but never touched it and sold it to me.

Looking st model number, manual says it's an 82 xj750seca USA. Odometer shows a little more than 4k miles, physically bike looks in good shape(even tho dead guy spray painted the engine and carbs with heat resistant black paint).

Carburator was in real real bad condition in the inside, corrosion, green like material all over. Also noticed that the jets seemed like OEM from a 650 UK version, exept for the air jets surprisingly. But maybe the jets were not OEM, it's the my first bike so i cant be sure.

Thanks to the church of clean, I managed to make it much cleaner, (yeah took me about 3h per carb just for the choke bowl passage lol)

Anyway, lot of ultrasonic cleaning, soda blasting, and elbow grease the carb is now "clean" (took me the last 5 days, I did the best I could)

So I've been working on the bike on and off for about a year now.

About 2 weekI ago I decided to finally get this bike running right! I've been dumb to buy ebay kits for the carb during this past year and obviously there's always something wrong. 2 of the 3 kits I bought came with Y403s fuel needles and bike won't even start when those are installed. (Will start with starting fluid, run like crap and not idle) one set have needles without any marking that work fine, and I feel like I'm almost there.
I need to fix an exhaust leak, and properly set the wet fuel level.

Bike runs, but not really well and I would not drive it until it's properly functional.

I am extremely limited in my budget now, wife is really mad and I am only able to use what I already own to try and make it right.

2 of the carbs drain screws are completely rekt, started by stripping, tried again with pb blaster, heat, untill I decided to drill a small hole and ez out/hammer in some special hex bits to get them off (that never failed me before) well they wouldnt budge, any more drilling and i might start having leaking bowls. Theyre gone.


Today I tried to set the wet fuel levels, the idea was to tie the floats close on those 2 carbs that can't drain, get a reading on the other carbs and adjust all of them, then I would reverse the process and tie up the good carbs, install the good bowls into the other carbs and tie up the ones that are set.

Imagine my nightmare.
On top of that I'm very limited to what I can use for the wet level adjustment, made this system today,
but i cant really make sure that carbs are perfectly leveled. After some adjustments, i managed to get almost perfectly 3mm but that sets the dry level at 20mm... from 17.5 in the manual (yeah i know aftermarket needle may play a role in that but still seems odd)
tomorrow I will work on my system so I can make sure to have them perfectly leveled. But I'm starting to lose my mind with the added complications of those not operational drain screws.

I noticed there are a slot exactly at the other side of the drain, same shape and but plugged with some kind of aluminum, as if factory made the same carb, but drilled one side or another depending on what they needed for a set, rather than designing 2 different bowls.

Would it be possible to drill the plug and thread the passage to add a drain screw?
has it been done ?

If you're still here I apologize for the book I just wrote, lot of venting, it's late and I'm exhausted, and English isn't my first language so it must be pretty painful to read, nonetheless if you made it through I'll take any advice that could help. (I can't buy a new carb, I'm beyond broke, so thats unfortunatly not a possibility.)

 

Okay to go over what has been done so far with another set of eyes. First when you had the carbs apart did you pull the pilot adjustment plugs from the top and remove the screws/spring/washer/tiny O-ring before cleaning? Two what was the actual cleaning medium? I'm not crazy about ultrasonics when it comes to hydrocarbon leftovers but to each their own, yes I feel your frustration having been down this road many times but it goes without saying all of the passages must be clean regardless and when I say clean I mean physically scrubbing with the little brush kit and passing little wires through the passages. The metering of these is super fine and precise, a piece of gunk that was knocked loose is enough to cause big problems. I soaked my carburetor rack for a few nights in carburetor cleaner. How I did this was disassemble the carbs leaving them on the rack and I built a soaker with two gallon paint cans soldered together at the rim then bought a case of cheap cleaner and drained the cans into the soaker, Ace hardware has clean new empty paint cans for sale and after cutting the bottom out of one with a can opener they can be soldered together with a soldering gun and 60/40 electronics solder but the seam must be liquid tight. While soaking the cans will build up pressure so you must burp them by slightly opening the lid. This was my church of clean and after a few days of soaking they were Zestfully clean to the point of eating off them. I can't stress this enough: clean clean clean.
You mentioned soda blasting, have you confirmed ALL the soda has been completely cleaned from both inside & out? The soda itself is destructive to the carburetor bodies and will destroy the machined surfaces.

Wet setting the bowls can be an exercise in frustration, I know you said you're on a super-tight budget and I don't like to recommend the cheap chinese made kits out there but there is an okay rebuild kit on ebay for $15.00 that has enough to get things going and I can confirm the needle & seat WILL work in these carburetors, I'm using them now. The seller is QYYDD and the specific ebay item number is 175601693707. The kit comes with #122 main and #42 pilot jets plus basically everything you will need to get things running well enough to ride. The kit was for all four carburetors but was missing a small thin washer so save all your old parts. The factory jets should be #120 for the mains and #40 pilot. Setting the pilot screws, I have the fine thread screws and the bike started and ran well with two full turns, I then balanced & sync'd them using gauges and colortune plug and this alone took over an hour. Make sure you have a good fan blowing on the engine while tuning.

Next did you pull the tops and confirm the slides? Are they free moving with no binding? Do the clunk test. How about the air jets in the top section? The manuals are wrong regarding the placement of the jets and there is an excellent write-up in the technical section of xjbikes.com regarding this.

Go to the "what have you done to your Yamaha today?" topic of the xjbikes forum and find page 412, this is where I started my journey with my 1981 SECA 750 carburetors. I've been wrestling & tuning them for a few months now and went so far as to put a small video camera in my airbox and record the slide movement in real time to get a feel for what's going on. Now I'm to the point of overpowering my clutch and I can pull the forks to the stops full throttle in 2nd gear when the motor passes the 7000 mark. To wet set the floats I used 4 chunks of clear poly tubing that I rigged with wire to stand up and mounted the carbs to a plywood wall using two engine carburetor boots, the tank was on top of a shelf. This way I could open the fuel valve and fill the bowls, open the bowl screws and get a reading then shut the tank off. With the carburetors on the wall I could then take the bowls off without disturbing the overall positions and carefully bend the tabs to raise & lower the floats then recheck again until I got everything level and to spec.
I feel your pain but these carburetors are not what I call for beginners, years ago I had a 1980 Honda CBX... yes the six cylinder and it used Keihin carbs which were far simpler for me, they needed constant adjustments to keep things running right.

Drilling & tapping the bowls, I've never done this and wouldn't recommend it. The drain screw has a tapered end that seals against a seat machined in the bowl itself and a standard tap is not going to replicate this. Sorry to say but you're going to need to replace the bowl.

Best thing here is patience, the more you have the more you will feel the reward.

 

Thanks for your answer. Carbs have been cleaned many times this past year, but 5 days ago I took it extremely seriously.

Every single jet, even the sides #36 emulsion (I believe) have been removed, carb completely dismantled, shaft seals replaced, all Orings replaced, new mixture screws, new 120 main, new 40pilot jet. Followed and applied the church of clean page the absolute best I could.

In the past, I did bath the whole rack into a water pine sol solution in the ultrasonic cleaner. Couldn't get it to run, started having gas leaks, and eventually gave up.

As said, when I started again 2weeks ago, I went above and beyond to research every single post and videos about this bike (mainly the carbs but more too)
Replaced fuel fittings with Viton rings, no leak, good size. Double #11 Oring for the shaft seals, lubed with red rubber grease (had that already but no silicone grease unfortunately).

Diaphragm are in good condition, polished the housing with 1000 grit sandpaper and lubricant. Clunk test pass no problem.

Soda blasting was properly done, didn't remove some of the stains on the inside of the carbs (my air compressor only goes up to 130psi) took a while but cleaned best I could, stains are greyish, only in 2 of the carbs, its not dirty or flaky, im just worried going harder would require sanding, removing metal and i think it would be worse. It's already day and night compared to what it uses to be.

Bathed them in simple water ultrasonic cleaner at about 65celcius for an hour, blown and dried with air compressor. Bath again, Inspected 4 or 5 times, washing and brushing with soft brush (not metal) if I saw anything else than the carb bodies. I am 100% positive no soda residue left in there.

I then spent 3hours on each bowl to get a massive carb cleaner squirt out of the choke passage hole, had to use a few things from needles, wire brush stem (excuse my French I'm not sure of the word) compressed air, carb cleaner, ultrasonic bathing, and repeat repeat repeat untill the big squirt.

Reassembled all carbs one by one, with new shafts etc. Being as clean as possible.
Once back togather with just the fuel tubes, I lightly screwed in the first rack, then lightly screwed in the second rack(with the idle knob).
I then clamped the carbs inline togather with 2 straight flat and leveled steel plates, before tightening the carbs togather with blue loctite. They are as straight as they could be.

Bench synced them after that, probably didn't do the best job, because I couldn't get all butterfly to be completely dark when holding to the light(like the church of clean mentioned.) I tried my best and spent hours but realised it might be that the butterfly are not perfect themselves. (Very little light pass through, nothing really bad I think, probably will be fine once tuned)

Other carb screws have antiseize , as advised in the church of clean.

All jets are to stock spec. Only thing I can't tell would be the needles because there is no marking on them, and since I don't have any OEM I can't compare. I just know they are not the same as the 2 other kits I have (y403s) and that the bike starts and run with them.

I will check out the kit, but I don't think I will buy them, I really can't afford anything right now.

Plugged the carbs in, brand new spark plugs, checked valve clearance. Bike starts and idle. Drove it on the dirt road, up to 4th gear, definitely not great, but considering that was only with the dry float settings, and that I noticed a massive carb boot leak when spraying starting fluid near boots (#3 and#4), I belive if I can properly get the wet settings right, and fix my leaks (boots curing now) I should be left to fine tuning. (I've already read posts about how to simulate yics tool with a rag or Tshirt, and saw some videos of tuning with bottles and 2stroke oil).
Idle screw set at 2 and a half turn out, for now.

Also when I did start the bike, I didn't attached the air filter/airbox boots, ive struggled way to many times with them, they're hard as a rock, and I'm afraid to damage them even more when using an heatgun and ton of slurs to pop them back onto the carbs. I'm getting a bottle of wintergreen oil today, so they'll soak and hopefully get soft again then I can use them. It's really not worth for me to risk breaking anything that I can't afford right now.

But for now, I need to first have the wet level set, and those drain screws are making it a real pain. Especially since my setup is difficult to remove and reinstall in the correct position/level, so if I have to switch every bowl, or tie floats in closed position etc, it adds room for error and false reading.

Air jets are correctly placed, ive read many times about the manual misstake, and made sure to triple check on reassembly.

If noone has done it then I will not do it, I will have to wait and save up for a set of decent oem carbs on ebay, in the meantime I will keep struggling to have the wet settings right while having to switch bowls, keep things leveled, and clean.

I learnt a lot the past 2 weeks been reading a ton of posts and I can't wait to have my first real seca ride. I hope stars could lign up and that I can find a deal with an oem set of carbs as soon as I can afford it.

 

Sounds like you've done a good job on cleaning. If you buy another set of carbs, you will have to repeat all that same work so I don't know what you will gain, unless you just want to use the bowls from the other set.

Trying to tune everything with the intake boots removed will change things. I understand the budget concerns. There are aftermarket intake boots available for both sides of the carb that are pretty reasonable in cost. These would be a better investment than a second set of carbs. Fighting dried out boots will make you want to drive off the nearest cliff.

You say it runs, but not great. What are the symptoms?

 

Thanks for your answer,
I really tried my best cleaning it. Well if I end up buying a new set of carbs, it would mainly be to get my hands on OEM jets, Fuel needles, and replace those 2 bowls that have an unusable drain screw. That would make it easier to adjust wet levels, and would make sure that I have the correct fuel needles.
Then over time, I can take my time cleaning and restoring the new carbs while enjoying my bike with the current carbs.
I see a couple carbs set on ebay right now for 140$ they obviously don't look great, and there is no certainty that the components are OEM, anyway I couldn't afford it right now..

I haven't tried tuning the carbs yet, I first need to set the wet float level (I'm supposed to be dealing with this is as I'm typing, trying to gather some motivation...)

Intake manifold boots of good quality are hard to find, over this year I purchased 2 set of aftermarket, but after a few times installing and removing the carbs, one set cracked very easily (poor rubber quality) the other one came with loose vacum ports, can literally remove them when trying to remove the cap, that for sure doesn't seal and so most likely leaks air.

I'm working on refurbishing the oem boots that came with the bike, using some sanding, rtv silicone, Teflon tape. They have cracks but I think it's doable, at least for now.

The boots that I didn't attached are the airbox boots, those are not cracked but rock hard and very hard to install(I heated them up with heatgun and pushed them into the airbox to remove the carbs, if I want to attach them back after installing carbs, I need to heat them up and somehow pop them back out onto the carbs. Very hard to do, and pretty high chance of breaking the rubber since I need to heat them pretty hot and pull/pry on them to make them pop out. Those are very hard to find, so far I've only seem one seller on ebay and online of aftermarket made in Japan. They're about $50 shipped. Obviously those boots aren't as important as the head boots for leaks.

I removed them and I'm about to soak them in wintergreen and alcohol solution for a few days, from research it really helps revitalize the rubber and make them very pliable again.

Symptoms wise, well I would say the throttle was very sensitive, had to go very slow on it or it would surge too high too quick, maybe a little run away too, but I'm guessing that was the air leak.
Bike would stall if releasing clutch without a really big amount of throttle in first gear. I think that is linked to the float settings being off, lack of power.
Once I get the wet level right, the airbox boots back in and attached, I will give it another try to warm up bike and start syncing.

If bike doesn't perform well after that I will start guessing my fuel needles are the culprit, since I have no idea if I have the right size, all I know is that between the 2 kinds I have, they're the only ones that can start the bike.

 

Your symptoms indicate too lean. The air leak you have found adds to this. Not having the airbox boots installed increases the lean condition also. The carbs not being vacuum synched can make it impossible to dial in the idle, and could also be your lean problem, or at least act similarly.

I'm not a carb expert, but the main jet needle should not have any impact on starting and idling. Not starting on one set of jet needles, and starting with the other sounds odd. Your description sounds like you cleaned the choke (enrichment) bowl jets properly. Does the bike respond properly to the choke? As in, after starting can you smoothly adjust the idle speed between 1100 and 4000 or so with the choke lever? This can be very difficult also until after a vacuum synch.

The low cost synch gauges on ebay will work if you can fit them into the budget. Use of the YICS tool is debatable (search this site for all the opinions). I've tried it...don't use it anymore.

The plan you have already stated is correct...fix your boots and floats, then vacuum synch. Trying to do anything else at this point will just be frustration. You might also add to your list, check compression on all 4 cylinders (more tools....sorry). Although with only 4k on the clock, I suspect your rings and valves are in great shape.

Also if you haven't found this section, scroll down to the Hitachi jet descriptions for the numbers you should have stock.

https://www.xjbikes.com/forums/threads/xj-parts-catalog-section-c-fuel-system.44642/

 

Thank you, ive already got this page in my bookmarks!

At reassembly after full cleaning, I installed those brand new y403s needles, and removed the unmarked one. Once I was done and carbs were ready for test, it wouldn't start, didn't matter how much choke I would try, will kind of start with starting fluid in the intake and die once it was consumed. I managed to get it to run while holding the throttle, but it was really bad, smoking rough, and would not idle, no matter how much I would turn the idle knob.

Removed carb and rechecked all jets, I was confident I didn't make a placement mistake because I quadrupled checked it all on reassembly. After confirming everything was correct I thought that may be the fuel needle(I'm talking about the needles in the slide, attached to the diaphragm piece).
Swapped them back to the unmarked one, (I did check and they are not the same size, diameter, etc).
Put the carb in, and bike started very quickly. That's why I think it was the issue.

I haven't messed with the choke yet to be honest, the lever and cable is missing(something else on the list), so I need to activate choke from the carbs directly. Bike usually starts without the choke, but I will definitely check next time I have the carbs in.
Last time I had the bike on, I set the idle to about 1100 1200 with the knob, there was some small up and down on the idle, maybe the leak?

Anyway I was able to rev it up pretty high, it just sounded a bit rough, not crispy. Little bit of white smoke from exhaust too while revving.
I have a vacuum sync tool I bought months ago, it's still in its box lol.

Will try it when I've got my issues fixed. You're probably right that it's too lean, ill check the spark plugs too and adjust the mixture screw accordingly!

 

What was the difference in the needle diameter?

 

I haven't properly checked the diameter, I took 2 of each needles togather and set them up straight vertically on the table, pointy tip toward the ceiling. Then tried to grab them at the same spot with my caliper horizontally, I noticed they were not the same size because when caliper was tight, couple of them would keep sliding through.

I had to do that because it's hard to take measurements of a cone shaped item, it all depend of where you take the measurement, diameter will change everytime something moves up or down.

To be honest I didn't enquire too much, I just needed to know if my unmarked needles were the same as the y403s, and figured it wasn't!

What is strange is that I found a very dark needle in the bag ive put all my carb stuff, I believe it was one of the needles in the carbs when I got the bike. It's marked y403s, so I assume it has been rebuilt before. Main jet was #112, pilot #43.(strange seems like a UK 650 stock version, but the airjets are stock 750USA)
I've seen in a post while researching this needle, that the aftermarket names of the needles changed from y-1x to y-xxxx, someone was saying Chacal told him. Post was talking about a different model tho, and I couldn't find any information about the correct new name of the y-14needle.
Bike was last registered in 1991, that's pretty much all the infos I have, no clue if the original owner swapped carbs...

 

Alright the wet level is correctly done now, having the carbs leveled properly was crucial, without it my wet level was correct at 20mm dry, when leveled it was correct at 17.4.

I will wait for my airbox boots to soak a bit longer in wintergreen oil before testing. Might also try the y403s slide needles again since it's easily accessible from the bike, I can run some test!

 

keep at it.. in the end they just leave.

 

Thankfully I was traded in for a newer model!

 

Update, after having the proper wet level set, brand new spark plugs, boots and air filter attached, I started the bike. Seemed just a little bit harder to start than without the airbox. But it starts, idles fine, even tho I still have a leak in intake boot #3.

Unfortunately I messed up touching the clutch cable while the carbs were out because I thought of deep cleaning the airbox, only to realise I had to take some engine mount bolts out and told myself he'll no.
I was struggling to reconnect the clutch cable the way it was it, clutch have always been extremely hard to press, so I put it back the way I could.

Noticed the cable was in very bad shape, and was rubbing against carbs for a while it seems like, the way PO put it was off, and I'm really wondering how it was attached to the engine with so much tension.

Anyways I did look up posts and managed to play with the whole system so I could engage the gears, it's not perfect but I'll do some more arrangements.

Now I just tried to ride a little bit on my dirt road to see if all the work on the carbs made it better.

Well it's worse than before now, bike wants to stall really bad when I'm releasing clutch lever, I really have to add a lot of throttle to start moving, then noticed a ticking noise, never heard that before, seemed like it was coming from the sliding needles, but I couldn't really be sure since it only happened when I was moving.

I thought maybe those unmarked needles was not the right ones since 99% of the carb rebuild kit I see online are coming with the Y403s slide needles for the xj750.

So I decided to change the needles, not too hard since I don't need to take the carb off the bike.

We'll bike would not start on it's own, I had to use some starter fluid and give it good throttle to keep it alive, even turned the idle knob all the way in and still won't idle alone. Only when holding the choke fully open it would barely idle.

Opened the mixture screw up to 5 full turn, bike still lean as he'll, carb backfires, and very hard to move in 1st, too many backfires I just stopped it. Didn't seem to have the clicking needle sound tho.

I'm quite confused now. I've put all the stock jets in fully deep clean carbs, new air filter, new spark plugs oil been changed 6months ago but I haven't ride more than 2 miles going up and down the dirt road.

I'm lost at this point, maybe I should put the jets that were in the bike when I got it? It was #43 pilot and #112 main jet. With I belive y403s feels like bike is running to lean no matter what, but with the y403s it's just really really bad.

Does anyone know if going lower in main jet number gets richer or leaner? And what about the pilot jet? I've got #40 in right now but I did run it with #43 last year and it seemed "ok".

 

On jets, the bigger the number the bigger the hole (more fuel).

It sounds like you may have pilot jets, or the pilot circuit still plugged. Can you see light through your pilot jets and run a wire through them? They are tiny holes. Regular carb brush/wire sets are way too big. Even most torch tip sets are too big.

Do you have an air compressor? With the pilot jets and pilot screws removed, can you blow air through the circuit and feel it coming out the 3 tiny holes in the top of the carb outlet, right where the top of the butterfly closes? You can alternately plug the pilot jet hole, pilot screw hole and pilot air jet hole with your fingers as you do this, running air through each part of the circuit and blocking the rest. With the pilot screw removed, you can also look down and see light through its orifice. You can't see down into the other pilot circuit holes directly behind this, but with the air you can feel with your fingertip if you have flow through them all.

 

I used brand new jets, I really went ballistic on cleaning, but I will check. Would spraying carb cleaner in the pilot jet hole work too? If liquid comes out of the small holes in the butterfly area?

I'll check soon, just got the carbs off the bike... again. I need to fix this stupid leak on boot #3 that's also raising concern.

I checked the spark plugs, even tho I mainly just used the bike by revving for 20min since I changed them, and they seemed very lean, clear grey/almost white color.

If jets passages are clear, I think I'll just try #43pilot jets and #122main jets, with the unmarked needles that seem to make it run richer... if it was plugged then I'll give it another try with stock size jets.

 

Sprayed carb cleaner into the pilots, all clear carb cleaner getting to the butterfly area with ease. Decided to keep the y403s needles and all stock jets, no change, won't start without starting fluid, won't idle. feels like I'm freaking cursed or something.

I'll attempt a last resort with #43pilot and #122main, with the unmarked needles.. losing faith

 

Definitely frustrating, good job sticking with it though. One more thing that might be a long shot, but its worth asking...are you filling the carbs with fuel with the "PRI" position on the petcock before trying to start? Just wondering if the carbs are empty, then after starting the bike on ether and the vacuum petcock opens, they start to fill.

 

I am using a portable gas tank, the carbs are full, I think this tank is continuously sending gas to the carb, as soon as floaters allows it. Flow is good.
I'm in the process of removing rust from the tank, I'm waiting on coating to arrive so I can start rust removal.

 

Ok there's no way this is carb related anymore, I mean I literally changed the jets to #43 and #122
I was able to drive the bike 3 days ago with #40 and #120.I could go any gear and over 60mph no problem(didn't try more on dirt road) It was a bit rough and I had to be very slow and the throttle or it would surge. But now no matter the carb settings, same thing happens when I release the clutch, rpm hard drop, power drops a lot, I struggle to keep it running if I try to fully release the clutch handle and if I do, bike stalls.

Could it be linked to the clutch cable? I messed up with it just before putting back the fully wet float set carbs. I'm starting to think my issue is coming from the clutch settings I did. I've never adjusted a clutch cable before and just read some posts yesterday and did the best I could this morning.

Would a badly setup clutch cable do such symptoms?

The whole carb thing makes no sense to me anymore, I spent the entire day switching jets, turning knobs and idle screws and the bike keeps doing the same thing.
Bikes idle fine unless I use the y403s needles. I can rev it up to about 4-5k rpm in neutral. I can get in first gear fine, but once I let go of the lever a bit too much, big power and rpm drop...

 

There isn't really any way a clutch could cause this. Have you had it up on the center stand with the rear wheel spinning free and cycled through the gears while it's running? Rear brake isn't locked up, right? Are all 4 exhaust pipes equally warm? Your description still sounds like it is running very lean with no power.

When it is running, can you kill individual cylinders by screwing the pilot screw all the way in? Or can you hear a definite change in idle speed or missing as you go to extremes in/out on the pilot screws?

You said you had vacuum synch gages, did you hook those up?

Since getting your leaky boots repaired, have you done the spray test again for vacuum leaks, including around throttle shaft seals?

 

Thanks for your answer. I will make the tests and let you know, shaft seals tested, no leak there. Only leak is on boot #3, I changed the gasket earlier and haven't done the test. I was able to run it much better with the same leaky boot few days ago, just that it was extremely sensitive to the throttle.
Since I changed the jets to 43 and 122, carb isn't popping anymore, I don't think it runs lean, I will need to check the spark plugs and see.
I haven't touched the idle screws since i changed the jets,
I think i noticed thats it's drinking gas faster tho.

I'm getting quite frustrated taking the carbs in and out all day long, and everything I try fail miserably.
I'm gonna go turn the mixture from 2.5 to 3.5 turns out, then do the tests you suggested.

The more I keep taking those carbs in and out, the more damage I'll do to those boots unfortunately maybe creating more leaks.

The clutch feels much looser than what it was before I removed the cable from it's housing, I couldn't put it back in there I was 5inch away trying my hardest.

I've rotated the star gear and try to adjust to have good tension, but maybe there's not enough and it doesn't engage when I release the clutch?

Anyway, going outside, I'll put some fresh gas and give it a try. Might as well change the oil, maybe ive got gas in the crankcase with all the tests I've done screwing with the bike.

Gonna follow your post tho and hope to figure it out. I don't want to give up but it's getting really hard on my head

 

Ok, so.
#3 boot still has a leak but much smaller than before.
All cylinders get hot, I can't tell if they're all equal, don't have a thermometer, touched one and it was way to hot for me to keep touching the others. But I do remember in the past, that the 2 right side pipes(when sitting on bike) were hotter than the others)
At some point I could hear a small ticking, coming from left side of the engine, even in idle.

I ran the bike for about 30min. At some point I lifted the small tank in the air, and managed to shift to 1st, release clutch, back wheel was spinning nicely, got 2nd 3rd, was doing great. That's when I decided to shorten my hose, removing the filter on it, and have it directly above the carbs for gravity purposes. Since that the flow was worse, I turned off the bike, disconnected tank and tried to blow in the line, air would not go through. Floats must've been up and carbs full of fuel.

I opened one of the 2 drain screw, and that carb was indeed full. Left it drain, reconnected tank, and sure enough flow resumed.

Since that every single try of getting into 1st and releasing lever was dropping rpm and if I kept engaging, bike would stall.

Tried to fully turn in mixture screws, ran through a lot of fuel and it wouldn't kill the cylinder. Turned all 4 mixture screws didn't seem like any change in rpm, waited 10min, cylinder would still run. Disconnected a few different spark plugs to make sure I would know what sounds to expect when a cylinder would die. None died after 10min all the way in. It kinda sounded leaner, but nothing crazy for being all the way turned in, little but of runaway when revving in neutral, almost no backfire from carba surprisingly. For being closed all the way..


Did the opposite and turn them all the way out for about 10 min, sounded richer and made more smoke little bit of exhaust backfire from time to time, mostly when revving, but nothing crazy either.

Tried to shift to first and engage clutch, but everytime it was about to stall, no matter how much I would throttle to compensate, rpm would go down to less than 1k while I'm all the way in full throttle with the clutch half way engaged.

My guess is I must've f***ed up my wet level and have the float closing at the wrong level. My levels were just about 3mm at 17.3.
Earlier when I last rejetted to #43 and #122, In despair I adjusted all of them at dry 17.5, clearly that didn't help.

I kept looking at the flow with the transparent gas line of the tank, and really noticed it was much slower than I thought, especially without a filter.

Do you think I should go down in dry level to see if it helps? And if it does redo the wet level?

 

That's a lot of info. A few things at first glance:

Are you running the bike for 30 minutes on the stand? You should have a big fan cooling the motor for runs of 5 minutes or so and still be keeping an eye on temps.

After the carbs are initially filled and they're just consuming fuel, you won't see visible flow, or it will be tiny. The floats aren't opening and closing like a switch. They find a level consistent with fuel being consumed, so the float valve is always a tiny leak when running.

Are you certain you aren't pulling a vacuum in your portable tank and stopping flow to the carbs? Does it have a vent? I'm not sure how your shortening of the line could change how the motor runs. Or was there another change you made at that same time as shortening the fuel line?

Some will disagree I think, but float levels aren't going to cause massive changes like you're experiencing. If the float valves are opening and closing and not overflowing, I wouldn't focus on them at the moment.

The pilot screw adjustment was just a test to see if they are working. Sounds like they are. Return them back to 3 turns out or so.

Keep your tests short and the motor cool. It's easy to keep plowing ahead while tuning, but you don't want to burn something up.

And again, you've got the synch gages, right? Being out of synch can do crazy things. Use the gages! At least get some kind of baseline to see if one or two carbs are wildly different.

 

Any chance something electrical is going on here causing the rough running? You have the correct jets in place and even if the floats were off a little it would still run & go acceptably well. Roast644 is right on the money regarding the carb sync, I didn't see if you had changed out the throttle shaft seals but this WOULD require a full sync of the rack. The book says the YICS blocking tool is needed but with patience you can do it solo by taking smaller steps and a little extra time.
Let us know how it goes and if you get stuck we're right around the corner.

 

I bench synced them and didn't touch the throttle screws since, I only touched the knob so I adjust all of them together.
The tank is a simple bottle there is a small vent hole on the cap, the tube is clear and not green(bought a long time ago, seem like they changed the color since)


Electrically previous owner had a weird setup, there isn't a fuse box and it seems like he has done some wiring job, there is fuses, I haven't touched anything because I suck with electrical stuff. Just reinforced 2wire by soldering them togather cause they had a bad contact and instrument panel wouldn't light up everytime before I did. Also yesterday I added a new solenoid, because the ignition button would work 1 out of 10 time, always been like that since I bought the bike and I had the part bought few months ago. Since that no need to bypass solenoid anymore to start the bike.

I got a lot to do today, not sure if I'll have time to work on the bike, I will try the vacum gages if I do.

I don't know why but I suspect gas in the crankcase, had that happen to me before on a riding mower and it was causing a lot of issues, maybe I'm paranoid but I will change the oil once bike warmed up.

I'll use a fan from now on.

Thank you guys, I hope I can figure it out soon.

 

It can be frustrating, keep us posted on progress.

Are the screws below what you are calling "throttle screws"? If you haven't touched those, you have not bench synched them yet. Adjusting those 3 screws changes how far open each butterfly is in relation to the others. It sounds like you were turning the idle adjustment knob in the middle that adjusts all 4.

Search on this site for posts on bench synching. There's several methods. You had the carbs apart to do throttle seals, so you need to do this.

 

No I touched them after I finished putting the carb back togather, making sure they all open the same amount at the same time. I haven't touch them since. I only used the main knob to adjust idle.

 

These ebay boots are garbage, as soon I as (and I was extremely gentle and slow) tried to remove the caps off the vacum port, all the ports came out, so obviously they don't seal properly...

Anyway I plugged them back upside down because there is a larger Grove on top, so it can seal better.

This is how it was after I just adjusted the needles to all be the same, and stabilized them.

Tried to adjust but no matter what I do, some of them won't move enough to get to the other levels.
I'm gonna do some research on how to use this thing.

I need to find good quality intake boots, ive bought 2 different ones already, first one they cracked instantly, and 2nd one the vacum port is lose from factory.

I got the oem intake but they got a few cracks, some that goes on the inside part. Also the parts that connects to the engine is not perfectly flat, showing some metal instead of rubber. I don't know if I should try to fix those and sand the mating surface to have it flat...

I think no matter the adjustments I'll do on the carbs, leaking boots are just gonna make it impossible to sync and run properly

Also loosened the oil filter a bit, oil smells a bit gassy, but color was great yellow and by touch it's pretty viscous, but it does have a small gas smell.

Not sure if I should do an oil change, this is the recommended valvoline 10w40 for motorcycle, changed 6months ago, but probably only used for 1 or 2 miles total.

 

I use the same gauge set and the needles first have to be zero'd and match positions exactly then the little regulator valves have to be set to just when the needles move slightly with each intake pulse. It's a bit tedious but they work well, everything is set to the #3 carb as that is the master. Bad boots on the other hand everything is out the window, no amount of tweaking is going to make it run right.

 

Thanks, yeah I'm struggling with the boots... I see PO had some attempted work on the oem boots.
There's some kind of grey silicone by the orings inside, and a little bit everywhere on the mating surface.

The cracks on the boot I think I can fix, but the mating surface I'm not sure... might have to sand it all down and apply a thin layer of high temp rtv. But again I'm not even sure it would work..

 

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I've got an extra set of boots. Used, but decent condition. PM me your address and I'll send them your way.