want to confirm next steps after smelling gas from oil filler opening

Yes, forgot about the Throttle shaft seals......as K-moe said .....often overlooked......a must if they have never been replaced.

 

I just replaced the throttle shaft seals. It's possible I messed something up, but I hope not. I'd hate taking them that far apart again. The intake boots looked solid (and weren't removed). I guess I'll know tomorrow afternoon.

 

Assume that you replaced the throttle shaft seals correctly, look elsewhere for a vacuum leak if you even have one......

If you have no vacuum leak, then sync'ing & colortuning should dial you in....

 

It's alive!!!

I started off testing for a vacuum leak and things checked out okay. The bike started right away, but without the choke it ran with high, but steady RPMs. So, I ran my first synch and that brought the RPMs down, but not enough. So, I dialed back the idle adjustment and that really helped. I Kist have had it open more than the prescribed "sliver." I then did all 4 plugs with the colortune. I had a hard time seeing the different colors. Luckily, my wife had no problem. Then I did the synch and the idle mixture again. Starts and idles much, much smoother.

Tomorrow, I check into why my brake light doesn't work. It did when I started wrenching and I haven't done anything electrical to the bike. I'm thinking it's just the bulb. The light comes on, but doesn't get brighter with either brake. If it's something else, I'll just have to start checking connections and circuits. If it was just the bulb, then I re-mount the seat and tank, and take it for a test ride.

 

ARGH! First thing I looked at was the fuse box. I snapped off the little tang that held in the fuse so, I'll be doing some wiring before this thing gets on the road.

 

if you have the original fuse box, get rid of it.....and replace with something newer......most are replacing with blade type box......me I would rather use a std fuse block.....bought this one a NAPA...six slot fuse block.....4 needed with 2 spare fuses.....

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It's the original fuse box; replacing it was on my list for later in the season. I looked for a low-profile blade fuse box today without any luck. Seems everyone builds them tall. Yours might be perfect. I wanted 6 slots, as well, for spares.

On the upside, I think I found the issue with my taillight. A PO wired in a brake light modulator. Looks like the connection let loose (the white wire should be connected to the yellow coming from the light fixture). Shouldn't take too long to clean this up.

 

Does anyone happen to know the wire gauge going into the original fuse box? I don't see any details about that in my wiring diagram.

 

I got the new fuse box in and got the taillight re-wired.

I fired up the bike and it started fine. When I started to take it off the choke, the bike ran rough and RPMs dropped. So, I shut it off and felt the exhaust pipes. 1&2 were cold. Everything worked fine 2 days ago when I did the sync and colortune.

I'm more than a little frustrated and disappointed. What are my next steps?

 

Try to start her again and see if it is the spark or fuel? You know the ones that are not running so once the bike is running just pull the wire and hold it to the head, should be able to hear and see it arc. Might have to put a spar plug in and then hold it to the head to check the spark.

If that is sparking give the float bowel covers a little tap with something blunt (not sharp or pointed) to see if he floats are stuck. Let us know what you find.

If you get too frustrated just take a brake and come back to her, a clear head is a good thing. I had to do that today when I found my clutch slave on my Madru 1200 is under the drive unit! It works makes things clear when you walk away and come back calm.

Kosel, how close are you to LaCrosse? I am about 45 mins away from there.

Happy 4th.

 

I forgot to add that after I shut it down yesterday, I did pull the plugs. They were wet. I left the plugs out and walked away. One thing I can think of is that after I did the running synch and colortune, I drained the gas from the carbs to do the electrical work. When I reconnected the temporary supply, I did tap on the bowls and I could have sworn that the gas stopped flowing. I haven't yet opened/smelled the oil filler cap for gas.

I'm stepping away for a couple of days and just trying to lay out my next steps to diagnose the problem.

@Timbox , I'm in Minneapolis, so LaCrosse would be a bit of a drive. If I get it running, I'd happily cruise SE Minnesota/SW Wisconsin and meet along the way.

 

Ok, starting from square one.

I testing al for plug and I have spark. Next, without removing the carbs, I checked the fuel levels in carbs 1 & 2. Number 1, was high enough that it was more than just an improper setting. At first, it looked good, but as I held the tube next to the carb, I could see the level slowly rise higher. Number 2 looked fine. I then drained the bowls for 1 & 2 and re-checked them. Even tapping on the bowl, I had the same reading.

I know I need to take the carbs off again and look at number 1. Either a stuck float or a leaking valve (though they were just replaced).

Is there anything else I should be looking at?
Does this explain the cold exhausts for 1 & 2?

 

Kosel,
If you have not taken those carbs to "Church" all the way, you can not be sure what the fuel issue might be. There are so many little passages, holes, rubber getting old and cracking it is hard to track carb issues when the job is only done a little bit. I would guess that if you don't take the time to take the carbs all the way down, clean and air blast all the jets and passages that you might be chasing issues for a long time.

When you tested the fuel level did you have the bike on the center stand? Most of us have build some type of stand to mount the carbs to. I hung mine from ratchet straps and then made sure they were flush and plum.

Once thing you can try, with the books off the back side of the carbs (air box side) you try to start the bike and then put you palm on the back side of the carbs of the cylinders that are not running. That might put enough force inside the carbs to brake lose any plugged areas. That is just to see if you can get it running. You will get some extra fuel that comes out the back side of the carbs when you do this. Keep us posted..

 

I took the carbs to church. Completely disassembled, soaked, scrubbed, replaced all the seals and o-rings and gaskets. All the carb parts, including new needles and seats came from XJ4Ever.

When I first set the fuel levels, the carbs were mounted on a homemade stand and the carbs were leveled. When I checked yesterday, the bike was on the center stand.

The bike ran last weekend when I did the sync and colortune. The current issue happened after I replaced the fuse box - I disconnected the temporary gas supply and drained the bowls to do the electrical work.

 

Looks like you found your trouble, the fuse box. I would go back and do a continuity check with all your connections. Good work on the connectors and how you have them bent and connected, very well done.

This is just a suggestion but I would go back and add heat and solder them. As the wire comes though the little tunnel of the clip, you can put the tip of the solder iron on the clip side and add the solder. It will wick into the wire and on the connector for a elctro mechanical connection.

The only other thing I can think of is just a trouble that started new and was bad timing as you did the fuse box mod. You would have to work your way from the plugs back through the wires and the coils.

Beast of luck and keep of the good work.

 

I hear ya man.... My carbs have been off 10 times in the last month, myself to blame I guess. But I replaced all the needles and set levels in a leveled test stand and it just seems to randomly change. I think the bike bouncing along allows the float to move better and you might get a slightly different level than just sitting stationary. I take the bike for a 2 min. ride and check again, now I have #1 not firing (cold) at start but it gets going when the rpms increase so I'll be tweaking that one tonight, think it's high and runs rich like yours starting out. I'm crazy frustrated to just get it back to where it was a month ago...

And now all that beating on the intake boots have given me vacuum leaks (I believe)... new boots arrive soon.

What's more... the bike ran really well for three weeks and I dropped it at the shop for a rear tire and it came out running badly. Kind of like why would a fuse box make a difference? I think if a needle is leaking very little it's when the bike sits the flooding builds up over time. Or they whacked something... I don't know....

 

I'm thinking that draining the carb bowls to do the fuse box is what caused the current fuel level issue. I'll tackle the number 1 fuel level and see where that gets me. Before I re-mount the carbs, I'll leave them in the rack with the temporary fuel line long enough to convince myself they're not leaking.

Once back on, I'll re-do the running sync and colortune. Then, we'll see what's next.

 

I'm at my wit's end.
I replaced the float valve assemblies with all metal from XJ4Ever, trimmed plug wires, got cables hooked back up and started it up. It eventually started, but didn't run right. After a minute or two of idling, headers for 1 & 2 were cool, where 3 & 4 were getting hot.

Right after I shut it down I checked a few things: fuel levels were within spec; plugs were wet; did not smell gas from the oil filler hole.

Despite all of the work I've done on it this past summer, this is the same problem that's been plaguing me all season and has kept it on the center stand in the garage. I'm just not sure what else to try.

 

You have a colortune plug? Put it in Cyl 1, then 2; watch what's happening. Could be waaaaay too rich, while 3 & 4 are much leaner (and thus hotter). Maybe they're missing, or not firing at all? Being able to physically SEE what's happening in there will be very helpful.

Keep in mind you can turn the electrode in the colortune plug, make sure it's somewhere you can see the actual spark, vs. just the combustion, then you know you're getting a reliable spark if it's not combusting thus leading to the assumption that, combined with the wet plugs, your carbs are pushing too much fuel - so much you're outside of a combustible air/fuel mixture.

Haven't read back over the thread to check, sorry, but have you tried physically swapping the coils/wires so if it's a coil/wire/cap issue, it should move to Cyl 3&4? (if you have, just ignore this)

 

I used a colortune earlier and I thought I did everything right, but will try that again. First, I'll confirm where the mixture screws are set. I haven't adjusted them since July, when I last fired things up.

I assume swapping the coils/wires means swapping 1 & 4 and 2 & 3. I'll try that, too.

 

I swapped the coils, so that the plug wire number ran 4-3-2-1 (left to right as you sit on the bike). Headers 1 & 2 remained cool.

I also checked the number 1 carb mixture screw. It was 2.25 turns from soft seat.

I will try the colortune plug next, but am not really sure what I'm looking for. is it the timing of the spark? Color? Intensity?

 

I think what Windterdark is looking for is the color of the colortune when it sparks. He thinks you are running really rich.

If you have changed over the plug wires from the normal 1-2-3-4 to 4-3-2-1 you might get a different reading. Let us know if the header pipes are now hot on 1-2 and cool on 3-4 with the wire swap.

 

2.25 turns out would be lean. Baseline is 2.5, and typically you'll end up with them at 2.75 or so.

 

Pipes 1 & 2 remained cool, even after swapping the plugs/coils.

Winch seems to weigh against Winterdark's thinking.

I'll try the colortune after work. Anything else I should be looking at while I'm at it?

 

Well, I am shaking my head a little too now, the trouble is not following the trouble shooting. Have you already taken the connectors apart and cleaned them on the bike? I would re-check that coil connectors as well. I think when we swapped the coil wires around we were hoping the different cylinders would start to fire.

If you have fuel in all the carbs and you have spark on all the plugs then it makes sense that your bike would fire and run. Tired I need to sleep on this one.

 

I've separately swapped the positions of the wires and plugs, so that would seem to point to either the engine or the carbs. The b1tch of it is that things ran fine for an afternoon. I know I had all 4 firing back in July, before I replaced the fuse box.

Since I just got another Seca 650, I'm thinking of taking those carbs to church and then swap them out. It means this season's a loss, but it should (should!) confirm or eliminate the carbs as the problem.

I'll still listen to any advice anyone has on what else to try or look at.

 

Tried a new set of spark plugs (or swapped plugs between "OK" and "Dead" cylinders to see if the problem follows the plugs?

 

I swapped the plugs after I returned the coils/wires to their original cylinders. No change, still cool headers on numbers 1 & 2.

A friend dropped off a compression tester. Would it make sense to check compression?

Right now, my plan is to remove the carbs from the "new" Seca, take them to church, and swap them out. Hopefully I can at least get it started before first snowfall. Of course, being in Minnesota, that could be as soon as next week.

 

Yes!

 

Checked compression, but I am not sure what to make of the numbers. My Haynes manual says the compression numbers are for the UK model only.
Cylinder 1: 130
Cylinder 2: 120
Cylinder 3: 125
Cylinder 4: 122

Anyone have any insight?

 

Looks okay, little bit on the low side though:

Cylinder Compression Gauge:

Yamaha recommends that you perform a compression test every 5,000 miles or so, and that you should record the readings, per cylinder, for future comparison and evaluation. The acceptable readings (specified at sea level) are as follows:

To do a compression test properly, you should first make sure all of your engine valves are properly adjusted to their recommended clearances, as valves that are too "tight" (not enough clearance) will allow the intake or exhaust valve to be open more than is necessary, or at the wrong time within the compression stroke cycle, thus bleeding off compression that would otherwise be developed.

http://www.xjbikes.com/forums/threads/compression-test-xj650.113151

Do not use thread adapters or the like on your pressure gauge, as the added volume of air space within the adapter will reduce the indicated pressure readings.

a) make sure the engine is cool/cold, 60F is the ideal temperature to take measurements at,

b) remove all spark plugs, and then stick the plugs back into their caps and make sure the plugs are grounded to the cylinder head (or even better, disconnect your TCI unit).

c) remove the airbox filter lid and the air filter.

d) make sure the battery is FULLY charged, and remains so throughout the course of these tests! It is actually recommended that for purposes of compression testing that the TCI be un-plugged and jumper cables to a large capacity battery (i.e. car battery) be used to make sure that the cranking speed remains pretty constant between each reading. Slow or sluggish cranking speeds will reduce the indicated compression pressure.

e) open the throttle FULLY and keep it open during testing.

f) crank the engine over until the needle stops advancing.

g) Let the starter cool down for a minute or so, then do the next cylinder, etc.).

h) If the readings are below spec, then shoot about a teaspoon amount of motor oil into each cylinder, crank the engine over a few revolutions with the starter (to spread the oil around), and then re-test each cylinder using the above procedure.

i) compare the two results and analyze.

j) keep all of your figures, and note the date and mileage from your odometer, so you can compare the next time you take readings (every 5,000 miles or so).


The specified compression pressures should be:

XJ650 and XJ750 air-cooled engines:
Minimum: 128 psi
Standard: 156 psi
Maximum: 171 psi
Max. variance between lowest and highest: 14 psi

 

As Chacal pointed out, the numbers are a bit low. Follow step h in his instructions (adding oil to the cylinders). If the numbers go up, it could be that the rings dried out and weren't sealing properly. Another reason for the low numbers could be as simple as your tester. It might be reading low. If you repeat the test with a second meter, you can eliminate this.

 

Compression numbers are low, but not so low as to keep the engine from running properly.
Since the problem is with 1 and 2 (each running off of different ignition coils), and swapping plugs and wires hasn't changed that, the problem will be found in the carbs.

 

Remembering this time to hold the throttle open all the way and comparing 2 different testers, I have revised compression numbers:
Cylinder 1: 144
Cylinder 2: 140
Cylinder 3: 144
Cylinder 4: 151

So, it's not compression and it's not a coil or plugs. Echoing K-Moe (and the voice of dread in my head), it's got to be the carbs. So, I'll use my just-received Deluxe Complete Rebuild kit from XJ4Ever to rebuild the carbs from the "new" Seca and will swap them out when done. With everything else I need to complete before winter, it'll take a while, bit I'm hoping to ride it at least once more in 2017.

 

Reviving this thread, now that spring is here in Minnesota.

I did not take my spare carbs to church. Instead, working with the carbs from this bike. I re-cleaned the carbs. First, I disassembled them and soaked in Berryman's and used all my little wires and brushes. Then, I put the carb bodies in an ultrasonic cleaner, heated distilled water. I sprayed carb cleaner through all the passages, to make sure things were flowing through everywhere and reassembled them.

I remounted the carbs, used the enrichment circuit and fired it up. Sounded good, but when I felt the pipes, 1&2 were cold while 3&4 singed my fingertips. This leaves me exactly where I ended last season.

If it has to be the carbs, I'm at a loss for next steps.

Also, would a moderator kindly change the title to "Kosel's 82 650 Seca"? Thanks.

 

In my limited experience, I've learned that if you cleaned everything but did not change the float needles and seats to new matched pairs (Metal), you are seeing one of the faults you had to begin with. If those two cold cylinders have rubber needle valves they are sticking closed. I went round and round with my carbs through multiple openings and settings until I sent them out for full replacements.

Or, those two floats are way out of adjustment and not opening. I'm assuming you you dry set and then wet set the floats?

Even then, after the bowl fills the first time and the needles get stuck in the seats, it doesn't matter that the wet test looked correct. The valve just never opens again to admit more fuel...

 

New needles and seats last fall. Wet set the floats about an hour before starting it up. I'll check for the needles stuck closed, but considering these are the same symptoms I had at the end of last season, I'm not expecting to be that lucky.

 

could be the butterflies on 1 and 2 are closed to much from bench sync.
bad spark plugs or arcing spark plug wires, bad spark plug caps, corroded spark plug wire ends
are you sure of placement of wires 1 and 2?
be careful of tunnel vision maybe its not the carbs

 

When mine were sticking, it was with brand new needles too... that's when I learned they had to be a matched set. When I went to the metal ones I never had another issue with that.

I did however bite the bullet and had someone here do a soup to nuts rebuild of the whole carbs... $400 later for that but reliable ever since.

The other folks here have also repeatedly said that if you give the bowls in question a few good whacks with a screwdriver handle, that might free them up for the moment and you will at least know the carbs are flowing. When I did that successfully before full rebuild it would let me go for a ride... but then they would get stuck again when the bike sat a little...

 

To verify it is easy enough put petcock to PRI for a minute or two . Put back to ON , open the float bowl screw if you get a good amount of fuel then that is good if only a couple of ounces this will tell you float is either not opening or just barely . Agree with XJ550H this could be a coil issue or plug wire / plug cap or a bad spark plug .

 

it is possible and something I will check when I re-pull the carbs. I remember seeing a uniform sliver of light through each of the 4 when I was done.

last fall I moved the plugs but 1&2 remained cold. I also swapped wires 1 for 4 and 2 for 3 - still 1&2 remained cold. I also trimmed all plug wires.

I'm not 100% sure what you mean by this. The plug wires are labeled and the #2 wire is too short to reach the #1 cylinder.

 

I'm adding this to the list of things to check. FYI - I'm using an auxiliary tank

Yeah. I have a set from a second 650 Seca as well as a spare set in rough shape. I'm strongly thinking about outsourcing the re-do of one of those.

 

Had time to check the floats today. They are working as they should. Before I pull the carbs again, I will explore valve clearances, check timing, and check coils, plugs & wires.

 

The fantastic news is that my cold cylinders were cured by @hogfiddles taking my carbs to church for me. The bike fired up and I have 4 warm exhaust headers!!!!!

I completed the running sync and got that dialed in. I then puled the Colortune out of the drawer. For whatever reason, it never seems to work well for me. I adjust the mixture, blip the throttle and don't really see a difference.

Rather than screw things up, I'll leave them as set by hogfiddles and get the mixture dialed in by doing plug chops.

So, in the past 14 months, I've:

• taken the carbs to church (and was left at the altar)
• taken the carbs to church again (and again left at the altar)
• outsourced my carbs to @hogfiddles (Success!)
• replaced brake lines with stainless steel brake lines
• rebuilt the master cylinder
• rebuilt both brake calipers
• new brake rotors
• replaced brake pads
• replaced rear brake light switch
• new tach gear seals
• new exhaust header gaskets
  
• rebuilt the gas cap
• rebuilt the petcock
• replaced the fusebox
• wired up the neutral light
• new speedo cable
• new tach cable

...and I'm sure there are some other things I've forgotten about.

It's been a long (too long), frustrating, and incredible experience. I've never worked on any motorized anything prior to taking this on and I have to say thanks to everyone that hung in there to help me along the way. Also, a shoutout to @chacal for his incredible service and knowledge.

 

Actually, given your lack of prior experience and the inherent problems associated with trying to bring back a 30+ year old bike with spotty (or little) previous maintenance, you've done quite well and should be proud of yourself!

 

Absolutely he should be. Most would have given up long ago. He stuck with it and now... Congrats!

 

I agree, you've probably learnt a HECK of a lot....theres NO shame in asking Hogfiddles for help, I would have too, by this time, and HIS 'Church of Clean' is probably way better than most of our attempts anyway.....and carbs CAN be a nightmare, on the XJ's, unless maintained/set up correctly, but once they are set, they are usually good for quite a mileage!!!

 

Saturday I rode the bike on a 5-mile round trip to show a friend. After I stopped to show him, it didn't fire up right away, but did start. No issues either way.

Sunday I fired it up to warm up the oil for an oil change. It started right up without choke, but sputtered a bit, so I gave it about 1/3 choke and it was fine.

Monday (this morning) I rode it to work. Unfortunately, traffic was terrible; a lot of accidents meant a lot of stop/go. By the time I got to work, it didn't have much umph starting out in 1st until I got to around 3k rpms. Once moving, it was fine.

So, I'm asking if this is what others call "bogging down". Also, have I correctly read that it implies a rich mixture?

Thanks.

 

Pods or airbox?
I don't remember--did you check shims?
New plugs?
Seafoam?

 

I have the factory airbox. I did have some difficulty getting the number 3 airbox-to-carb boot to seat. When I would tighten the clamp, it would un-seat the boot. It looked fine before I put it all back together, but I will check with an inspection mirror when I get home.

Shims are all in spec. Double-checked while I had the carbs off.

The plugs were put in last year and only used in the garage during all this work, but not on the road. I cleaned them up with a brass brush before I did the 5-mile road test.

one possibility is that I put oil in the cylinders and tank for the long winter. I know the oil in the cylinders burned out when I was warming it up to do the running sync. And, I rinsed the tank with a bit of gas (and poured it out) before re-mounting it. I then put about 3 gallon of non-oxy in the tank.

I should put the Seafoam in the gas, I assume?