#1 & #3 not firing when cold - hmmm

[tab1324]

It's an 82 XJ1100 first of all... I've read the repair section on coils which seems to indicate that #1 and 4 run together... So, here's the skinny.

I've posted recently about burning oil when the engine is cold - also about rough idle when cold. For these reasons, I've been tinkering with starting on different choke settings, leaving the bike on the center stand overnite so oil wouldn't drain through worn valve guides / seals... I'm checking the plugs frequently while all this is going on and have found that the #1 and #3 cylinders are wet and sooty - presumably from oil. The pipes smoke for a while after it's started cold and then it goes away. The time it goes away, the bike runs better... HMMM So I went a step further and felt the pipes... Again, #1 and #3 are cold while 2 and 4 are hot.

So I was talking to a buddy who used to work on bikes and small engines and he suggested that maybe #1 and #3 fire off of the same coil and that the coil may be bad. If it's not firing, the plugs would be wet and sooty because the gas isn't burning - or even a week spark may not be enough to complete ignition.

Is there any merit to this line of thought?

The other very interesting piece of this is that I just changed the oil the other day and after taking on a couple short rides, the oil level has RISEN above where I had filled it - unburned gas perhaps???

It's not that I can't accept the bike burning a little oil or even deal with fixing it but maybe I've stumbled accross something here - it seems to make sense.

Any ignition gurus out there??

Tom B.

[RUSH]

carbs flooding. pull the plug wire off at cold idle and if idle changes coil should be good. possibly bad floats and or petcocks?
if idle shows no change check spark plug caps and wires for spark, then check coils with mulit meter.
Miles on the bike? how long in storage if at all? how was she running before now? modifications to carbs or fuel delivery?
INMHO its not unusuall to have some oil at startup after sitting for many months, however if the oil level has risen it is probably due to fuel leaking past the carbs and into the cylinders. dont run the bike for any length of time with fuel in the crankcase.
oh yeah, if you had a problem with the ignition you would feel that you weren't running on all cylinders when you took her out. IE, lots of reving to take off, and no power. if she behaves like normal its probably the carbs and petcocks.

[tab1324]

I'm convinced it's a spark issue

I just went out and checked the bike again - replaced plug cap #1 with the cap from #2 (which the pipe was hot). No change. I pulled the plug from #1 again and it's soaked with gas. I even pulled out a qt. of oil to compare the smell of the plug to - it's gas definately.

I have done as suggested and pulled the plug wire during idle - idle doesn't change. Once the bike warms up it runs sweet so I'm thinking that the heat is enough to ignite the gas after it's warm.

They're new plugs - I had this same problem last year but just lived with it.

I'm planning to test the plug caps and wires for resistance. Anyone know the numbers I should get?

Thanks,

Tom B.

[ratbyk]

Just where is your extra oil coming from if the carb/s aren't flooding? Fix the carbs needle and seats, float level and then worry about the plugs. Oh ya, change your oil before ever putting that engine to work.
Ken/Sooke

[hollywoodxs11sf]

Do the coil wire swap. Instructions are here on the site. Takes about an hour and a half. I had problems with my bike occasionally running on 2 cyls, and , after the coil wire swap, everything works as it should, ignition-wise. Even in the rain!
All specs and readings are laid out in the tech tips area.

Now I have to deal with my over-rich fuel mixture that's been giving me black sooty plugs and 25mpg. I know my ignition is top notch, though!!

What kind of plugs are you using? I'm running NGK BP6ES.

[TopCatGr58]

Hey Tom,

I re-read your original post about Idling/Starting problems. It looks like your thread got sidetracked, but instead of posting NEW THREADS, if you just repost a reply to one that you started to REFOCUS folks in addressing your specific problem, AND ALL of the previously posted info will still be in the same thread, so folks can see ALL of the history of the problem, and then any things you've tried since, also being posted in same thread, then "WE" can more effectively trouble shoot this problem without repeating ideas/suggestions, etc.!

I fixed up an 82 XJ last summer and rebuilt (cleaned) the carbs a few times. I never did anything other than the "bread tie" synch job on them and it ran pretty well all year. This year, it's running about the same. It starts a little tough sometimes and you have to let it warm up a bit before riding otherwise you have to rev it higher and slip the clutch in first gear or it will kill.

So the question is - will a synch job fix this or am I looking at a jet or choke problem. The idle is "fairly" smooth at @1000 rpm. Could maybe be slightly smoothed out - jets or synch???

The other item worth mentioning is that I have quite a dirty air filter. I need to replace it but haven't done so yet. Could this cause or contribute to any of the above?

I don't know what else to do to the carbs other than just replace the jets. I'm planning to get together with 2fast to synch the carbs soon so hopefully that will smooth out the idle.

Any suggestions? Tom B.

So..... as you stated before, it ran okay PRIOR to your cleaning the carbs, and then for the first year after the cleaning. However, the following year, it started acting poorly, and your description of needing higher revs and slipping clutch more is classic for a lost cylinder, or even 2! Like you said, the ignition works on 1-4 pair and 2-3 pair, but your problem is 1-3!

You said you changed the plug caps from 1 and 2, but what was meant was to actually swap the entire wire and cap combo from the other paired wire for #1 which is #4, and the same for #2 and 3, in other words, put the "hot wire" from #4 plug on the #1 plug and vice versa. PUT NEW or cleaned dried plugs in, and then try to run it. IF the hot cylinders follow the coil wires, then you have poor wires/caps. IF the cold cylinders stay the same, then you are pretty sure it's a fuel problem.

You will probably need to drain and change the oil IF you have more oil now, due to flooding fuel leaking into the engine, do the dip stick in oil and then try to light it, if it burns, there's gas in oil!

And you should probably pull the carbs back off and RECLEAN them, paying attention to float needle valves, floats, screens, etc.!

Let us know what you find.......IN THIS THREAD!
T.C.

[tab1324]

sorry for "re-threading"

Sorry - I figure people wouldn't respond if I didn't post a new thread with my recent findings... I'll stop that. Although I just filled in a bit in another thread about the jets.... For those who havn't read it..

tonight I swapped the #2 and #3 plug wires to see if the problem would "move" to cylinder #2 since the same coil fires both right? Well, it didn't help at all. I didn't change the plugs so that they were dry in 1 and 3 however - would that make a difference? I haven't done any resistance checks but now I'm thinking it must be the jets as they're the only thing I haven't replaced or repaired in the carbs.

To be correct, the bike didn't run when I bought it last year and after repeated cleaning, repairing and replacement of float valves, seats, screens, setting float height, repairing slide diaphragms - The only thing I didn't do was replace jets. I did clean them and sometimes I had to scrape them clean with a small (eyeglass) screw driver. Could I have damaged some of them???

Also, I thought last year as I was having starting and idling problems, that it was carb related and I opened up the carbs and cleaned (drilled with a very small drill) the "choke jets". I couldn't get them clean with a wire - they were very heavily plugged... It may have been in cylinders #1 and #3 - I don't recall but it wasn't all of them. So could my problem now be that it's sucking too much gas when cold starting??? The bike does start and stay running since I've drilled the choke jets but it's still rough and #1 and #3 are soaked.

Last year the compression check was very good - don't recall the numbers but they were all high and very close in numbers. I want to say around 110-120 psi?? Haven't rechecked this year so far.

Sorry for the length of this and for my other re-threads...

Tom B.

[don07tncav]

Please don't be sorry!! The more information you provide the better these gurus can trouble shoot.

[randy]

Tom,

If by the term "choke jets" you mean "pilot jets", then go ahead and but a new set.

It is not advisable to drill out any jets, but if you do, then you have to do all four carbs the same or the engine will never run correctly.

Anything you do to one carb affects the entire engine.

Consider this. You have four individually carburetted engines all attached to one crankshaft. They have to be syncronized to work efficiently, otherwise they work against one another.

[tab1324]

I think I screwed up big time

Well I think I found the problem tonight with my rich running, not firing, starting, idling issues...

Last year when I was having a problem starting I took off the float bowls and on cylinders #1 and #3 I used a very small drill bit to open up the "choke jet"... Well, tonight I thought I would compare the "vaporizing" action of the drilled out jets vs. the cleaned with a wire jets. WAAAAY different. The drilled ones just let fluid flow through them while the cleaned ones spray the fluid..

So I'm looking for (2) float bowls that would fit a 82 XJ1100 or any suggestions on fixing mine.

I thought maybe I could find a very small thin piece of solid rubber that would hold up to gas. Could I put a needle hole in it, push it down the choke hole and think that might work?

Or am I better off drilling out the other two and just using much less choke (if any)?



Tom B.

[randy]

Don't alter anything else. Get replacement bowls and start over.

BTW, If you're going to be 'poking around' in your carbs, get yourself the right tools. Dennis Kirk sells the wire cleaner set made just for carbs to clean out jets.