carb jet issues,

my 82 xj650 has pods, straight exhaust, shimmed needles, idle jet from 40 to 43 and mains from 110 up to 120. the bike idles the best it ever has, but when i accelerate the bike seems to bog or sputter,
i was wondering if the main jet is too big at 120. it still seems a little lean tho? i did nothing but shim the needles up, i did not make them thinner. i also tryed taping the pods off just to see if it was getting too much air, it ran worse. Any suggestions? other than putting the airbox and cones back on.!

 

the air box is long gone, ive chopped the tail and seat so no room for box anymore, boo hoo

 

#120 main jets for a 650 is way too large, and shimming the needles just makes the situation worse. #43 might be one size too large for the pilots, but you can probably get by with them if you crank the mixture screws in a bit........although I would recommend the use of a Colortune plug to adjust the mixture screws, rather than guessing. And of course re-synch the engine, and check/adjust the valve clearances if you have not already done so.

 

+1 your mains and needle shim are causing the bog. Way too rich.

 

if you think your lean, try this, 4th gear at the rpm you think is lean at about 3/4 throttle. now close the throttle as fast as you can and see if you notice a slight surge forward.
only lasts a instant and sometimes doesn't do anything.
if it's lean, you cut the air and the mixture improves for a instant and you can feel it
but your way rich so start with that

 

Thanks Chacal,
my bike was so lean before, so i might try taking the shims out and putting in a 116-119 main? I'm going to try the 43s. my valve clearance is good too. thanks for the quick reply, this is one of the last things i wanted to do before paint.

 

Whatever you do, do ONE thing at a time....

 

Now I took the shims out and it stopped bogging on acceleration, but now it won't idle. Just got new intake boots in the mail, putting those on now.

 

New Boots are so snug, Having a bitch of a time getting my carbs back on. I cut out the shape of the seat and I gotta fab that so I stop sliding back, im really gonna have racing stripes in my shorts from the tire!

 

does anyone know the size of the holes for a #118 and #42 jets? cant find a chart with the 118,

 

1.18mm and 0.42mm diameter............

 

You'll find that the same thing works for valve shims. The nomenclature is just a rework of the measurement in mm.

 

are you going to ream your own jets?

 

So I had my stock jets of 110 and 40 just sitting here and 120 /43 seemed too rich, so I was thinking about reaming the 110 to 118 and the 40 to 42 just to try it. But last night I got my bike to idle and accelerate great with the 120/43 jets in. Maybe I won't ruin those stock jets just yet.

 

I can also only find a drill bit for 1.15 mm

 

You need to know where to look.

I can't seem to link it without getting a redirect to their web provider, but Grainger carries drills in that size. Most other industrial suppliers will too. McMaster-Carr is another that comes to mind.

 

a reamer is what to use, you could try one of these
https://www.mcmaster.com/#reamers/=1dser0s
but just buy new jets
Reamer
Dia. Flute Overall Number
of Flutes Cutting Dia.
Tolerance For Use On Each
Straight Flute
0.0460" 1/2" 2 1/2" 4 0" to 0.0002" Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel 8803A109 $18.93

 

For jets it really doesn't matter if you use a reamer or a drill. The work is being done by hand, so the drill bit isn't going to waller out the hole like a power-driven bit will.
If we were making a hole that required something to fit snugly inside of it, or were making new jets for sale I'd agree (drill undersize then ream).

 

true, your going to ruin it either way
drills are made under size because the holes they make are bigger than the drill, not so with reamers

 

Drills actually aren't made undersize. Take a micrometer to one. The size they are marked is the size that they are (unless you buy crappy drills).

 

Ok, i don't make this stuff up
https://drive.google.com/open?id=1NYaWl6FiEFmVVSHDeMt6NJpwrACrfw-E

 

Neither do I, and I never claimed that you do.
This is the first 1/4" drill that came to hand out of my collection.


Drills can, and almost always will drill slightly oversize from their dimension, but that's due to a combination of the type of fluting used (to allow for rapid material removal), tool flex, and whatever the inherent inaccuracy of the machine that the drilling is being done with is (chest bit, handheld electric drill, crappy drill press, good drill press, lathe, milling machine, etc.). When drilling a very small hole by hand, with a pin vice, very accurate holes can be easily made. The oversize (and honestly out-of-roundness) of a drilled hole tends to increase as the size of the bit being used increases (though there are other factors that cause the hole ot be oversize, as mentioned above).

As for actual drill rod/bit size, that will vary due to the nature of mass production of disposable tooling (particularly consumer-grade stuff), but there is no standard (that I'm aware of) that calls for them to be intentionally made undersize while being stamped with anything other than the correct undersize dimension.

I'll also withdraw my statement about crappy drills. While true, it's not just the crappy ones that can measure slightly differently from the nominal dimension stamped on the drill.

TL/DR: Redrilling carb jets is a common, and longstanding practice. It works because the holes don't have to be drilled to absolute perfection for the jet to function properly.

 

well sometimes i do.........did i ever tell you about the time.........

 

LOL

 

Yup.....

 

So I got my bike to idle great and accelerate good with the 120 main and 43 idle, I know it's a little to big for a 650 but I'm still getting alot of popping when I let off the throttle. I always thought that was from being too lean. Everything else is fine except the popping. I was planning on going to a 118 main, and 42 idle until I heard the popping. What to do?

 

Does anyone know if RamAir pods are any good? Or if they fit a 650? I wanted to get some better quality pods than the 10$ ones that don't really do anything.

 

Buy some k&ns, take a knife to the sharp corners inside them, oil them and enjoy. Those cheap chinchong things don't even filter..
No more to say really.

 

Old post I know, but:

The one thing that makes the biggest difference - what size pilot or pre- final hole you use. If the finished hole needs to be 12 mm, you drill a 6mm pilot, then use a 12mm, you will invariably end up with a 12.2mm hole.
However, if you drill a 11.5, then finsh off witha 12, you might get very close to 12, maybe 12.05.
Just what I've found...

 

My guess if it is popping your synch is off slightly you probably should start their .

 

Did you color tune each cylinder? Also uni pods or k&n are good. Buy waterproof pod prefilters for when it rains. Outerwears makes a good set for uni and i think k&n make their own.

 

I just started to see some white exhaust on pipe #4, I assuming my rings are shot. It just started so Im thinking that's funking up my synch? All my valve clearances are correct, I only bench synced my carbs a month ago. Would the shot rings cause backfire?

 

White smoke isn't oil. On an aircooled engine it's indicating that condensation is evaporating from inside the pipes.

Popping on decel can also be from being too rich, and the excess fuel igniting inside of the exhaust pipes.

 

[QUOTE="k-moe, post:

Popping on decel can also be from being too rich, and the excess fuel igniting inside of the exhaust pipes (just like flicking the engine cutoff switch will).[/QUOTE]
Ok, that makes sense. It is like a fast firecracker popping. Thanks,

 

Kmoe is right. To know for sure how to proceed you need to colortune to make sure each cylinder has the proper air and gas mixture. This will help with poping and your idle.

After you colortune it at idle you might notice after running the engine hot and at stop lights it will develope a slight hanging rev. The hanging rev is from running lean. If this happens you can either adjust your floats or put your hand over the tail end of your exhaust and feel the air flow. The side that is faster needs to get enriched via the air mixture screws. If both sides are fast increase all by small and even increments. Colortunes are great but with jets and pods its alil more tricky. Once you think its all dialed in put in new spark plugs and ride for an hour then read the plugs and adjust.

 

wtf?

 

Use the force...

 

If you are using 2 into 1 exhaust you can feel the difference in the rate of air flow if 1 or 2 are running lean vs 3 and 4. Try it. Run rich on 3 &4 and lean on 1 & 2 then feel the exhaust pressure. Its not an exact science and some might think inam crazy but it helped me isolate which side was running lean.

 

That does work, unless you're using the stock exhaust setup. However, it's almost as tricky as synching four carbs by ear. Takes practice.

 

ok, pressure. your not crazy but if one side goes faster than the other, that would be crazy

 

I need a rear brake pin and arm. I need the pin that turns in the brake plate to open brake pads. That pin and arm that are attached to the foot brake rod.
My safety bar bolt snapped and that arm and pin got bent and stripped. Wtf? Any suggestions?

 

Wtf? Really, do we need to swear?
Anyway, the bolt was rotten, it snapped, the brake mounting thingy turned and bent the actuating lever - you were lucky not to end up on the road. Then you might be saying wtf?
Actually, it's not strictly my place to say this, but this post should be in a seperate thread.

 

We have those parts in stock! Just send me an e-mail with your needs (model and year, too) to: info@xj4ever.com

 

We prefer one thread per-bike here, that way we know the whole history and can give better advice.

 

Well..since we talking about jets. I'm brand new to the XJ world and I just bought 1982 XJ650 Seca. I have an RJC frame (I'm in Canada) and the engine numbers don't match, so I'm not sure if the motor is the Canadian version or not? It's non YICS as well, has an oil cooler and double front disc brakes. Anyway......back to the jets. I cleaned my carbs a few days ago and found that the Main jets are #112's and the pilots are #43 and the jet needles are Y-11 except for the #4 carb which has a Y-10 for some reason. The pilot air jets are #195's except for carb #2 which has a 205 and........the main air jets are #50 oh and also
I have the air compensator jets on the intake side and they are #36 and of course one carb is missing one. I would like to set the carbs back to stock for Eastern Ontario conditions. I'm hoping you guys have suggestions for stock jetting and needles. I'm thinking that I should go #110 mains, #40 pilots, but I'm really not sure about the needles??

 

Please start a thread for your bike in the Technical Chat section.
Your jet situation implies that there might be other things that aren't quite right.

 

Y-11 needles are typically only found in Euro/UK model carbs:

RJC models should have "YICS" engines.

What is the number stamped into the engine case?

The oil cooler is correct for a Canadian RJ or RJC model.


CARB SPECS: THE CHEAT SHEET:

Here are all the different stock carb specs (carb model numbers, jet sizes, tune-up info, etc.) consolidated into one happy little group of information, so you can print this out easily when you are working on your particular set.


XJ650 Models:

Years & Models: 1980-1 XJ650 Maxim, Midnight Maxim, and XJ650RJ Seca USA models
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 4H700
Main FUEL Jet Size: #110
Pilot FUEL Jet Size: #40
Main AIR Jet Size: #50
Pilot AIR Jet Size: #195
AIR COMPENSATOR Jet Size: #36
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-10
Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
Idle RPM's: 1,050 rpms

Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")


Years & Models: 1980-1 XJ650 Maxim, Midnight Maxim, and XJ650RJ and RJC Seca Canadian models
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 4H800
Main FUEL Jet Size: #110
Pilot FUEL Jet Size: #40
Main AIR Jet Size: #50
Pilot AIR Jet Size: #195
AIR COMPENSATOR Jet Size: #36
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-12
Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
Idle RPM's: 1,050 rpms

Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")


Years & Models: 1982-3 XJ650 Maxim USA models
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 5N800
Main FUEL Jet Size: #110
Pilot FUEL Jet Size: #40
Main AIR Jet Size: #50
Pilot AIR Jet Size: #205
AIR COMPENSATOR Jet Size: #36
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-10
Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
Idle RPM's: 1,050 rpms

Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")


Years & Models: 1982-4 XJ650 Maxim Canadian models
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 5N900 or 5U900
Main FUEL Jet Size: #112
Pilot FUEL Jet Size: #43
Main AIR Jet Size: #50
Pilot AIR Jet Size: #205
AIR COMPENSATOR Jet Size: #36
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-10
Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
Idle RPM's: 1,050 rpms

Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")


Years & Models: 1980-1 XJ650 4K0 and 4K1 models (UK/Europe)
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 4K000
Main FUEL Jet Size: #110
Pilot FUEL Jet Size: #40
Main AIR Jet Size: #50
Pilot AIR Jet Size: #195
AIR COMPENSATOR Jet Size: unknown
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-11
Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
Idle RPM's: 1,050 rpms

Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")


Years & Models: 1982-4 XJ650 11N models (UK/Europe)
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 5N900
Main FUEL Jet Size: #112
Pilot FUEL Jet Size: #43
Main AIR Jet Size: #50
Pilot AIR Jet Size: #205
AIR COMPENSATOR Jet Size: unknown
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-11
Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
Idle RPM's: 1,050 rpms

Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")


Years & Models: 1982 XJ650 14R models (UK/Europe)
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 5N900
Main FUEL Jet Size: #112
Pilot FUEL Jet Size: #43
Main AIR Jet Size: #50
Pilot AIR Jet Size: #225
AIR COMPENSATOR Jet Size: unknown
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-10
Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
Idle RPM's: 1,050 rpms

Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")

 

You guys are so awesome here with info. As soon as I get home I will grab the engine# and post it.
**K- Moe, Im not sure how to start a new thread here. I've searched around, but it seems like I can only start a new conversation, but not a thread. What am I missing, I'm sure I'm probably just overlooking something really simple.

 

I think I see the problem. Onsome browsers the "Start New Thread" button may be partially obscured by the search box. It's in the upper right of each sub-forum page, straight across from the light blue bar that shows what forum tree you are in.