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Really wierd caca going on here..


spEEdfrEEk

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I'm getting a slight "lugging" of the engine in neutral.

Doesn't happen as long as the clutch is in. If I pull

the clutch in any gear (including neutral) everything

is hunky dory at idle.

However, if I'm in neutral and I don't squeeze the

clutch, the motor will start to lug a bit. It will even

stall if the engine is cold.

Thoughts?

TJ

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'97

Relevant mods: DynoJet stage 1, K&N Filter, Jardine RT1

slipons.

Thing has been in perfect tune for years. (did the

dyno runs myself at a local dealership)

This quirk is fairly recent, like within the last month

or so. I'm just hoping it's not gearbox or counterbalancer

related (or anything cryptic like that).

I don't see how it could be valve clearance, and it's

definitely not a CCT issue. (no rattles or clacking, etc.)

TJ

year of bike?

list of mods?

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Interesting.

Lugging goes away WHEN the clutch is engaged.

Question, what is your RPMs when this happens? Maybe your idle is set a tad low and the natural drag of the gearbox spinning when the clutch is disengaged adds enough drag to strain the motor. If it goes away by bumping the idle RPM up a bit, that might just be all the problem was.

I'd recommend buying B-12 Chemtool (Wal-Mart) or SeaFoam (same stuff, other stores), and run at least 1/2 the bottle on a full tank of good gas. It's a solvent that cleans the fuel system. Make sure you don't have contamination or a clogging injector. If it started fairly recently, the most obvious cause would be tainted fuel.

Also, although not as likely, when, if ever, did you last change your fuel filter? I did mine at 50K just to be safe.

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I don't notice any engine speed difference in neutral regardless of clucth in/out.

Assuming idle is correct and not extremely low...

Even when you are in neutral, there are a lot of parts turning in transmission and half the clutch basket, which stop turning when the clutch lever is pulled in to disengage. I think a bearing or bushing behind the clutch basket or in the transmission.

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All good ideas.

I can set the idle higher and prevent it from

stalling, but it's an abnormally high idle to do so.

Levers are stock and adjusted pretty well.

I'll bleed the clutch check and that first. Then

try the chemtool (never used it before) and see

if that helps. If so, I'll prolly overhaul the carbs.

I hope it's not a bearing issue. That would mean

more work than I have the time for right now..

TJ

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If so, I'll prolly overhaul the carbs.

Didn't think of that. When was the last time you had them checked to see if they are synchronized? Not sure if that would be an issue, but....

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Anything that gives you less power may cause this. The drag of the transmission is very small, but if the power is decreased, the drag of the transmission will have a greater effect. Like many/most of us, you know your bike very well and picked up on this.

So....a tank of borderline gas, a little dirt in the carb, dirty air filter, deteriorating spark plug, tightening valve...all these are possibilities.

Now on to the Probabilities. Something downwind of the clutch and before the output shaft is offering increased resistance to movement. That's not a pleasant thought. Change the oil and see if there is an improvement. Search the drain oil for physical contaminent.

If you feel performance loss....harder starting, stumbling, rough running, then its most likely one of the possibilties I mentioned.

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Make sure you don't have contamination or a clogging injector.

I can tell you that it is NOT a clogged injector. :icon_biggrin:

Yeah I picked up on that also.. but some people not so good at that reading thing.. :icon_whistle:

Sorry....I forget that not all of us are blessed with FI. Still, the issue with fouling in the carbs is just as important an issue to address. Run B-12 or Seafoam somewhat regularly and you'll never have that issue. :icon_biggrin:

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Now on to the Probabilities. Something downwind of the clutch and before the output shaft is offering increased resistance to movement. That's not a pleasant thought. Change the oil and see if there is an improvement. Search the drain oil for physical contaminent.
Cut the oil filter apart too and see what it has caught.. Filters can tell you a great deal..
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After you've changed the oil and checked for contaminates, and the problem still persists, pull the clutch cover and remove the springs, pressure-plate, and clutch plates. With the trans in neutral, try to rotate the inner hub. It should spin easily and smoothly. If not, your screwed.

I will note that I have never heard of a clutch basket or trans bearing failure in a Bird. Good luck.

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My 1st guess is carburetors/fuel delivery. My second guess will be Battery/charging circuit.

First guess.. Vacuum leak or clocked ports, causing an idle fuel mixture problem, where the motor has no power and is easy to stall. You said "I can set the idle higher and prevent it from

stalling, but it's an abnormally high idle to do so." this is a tell tale sign of this condition.

It usually does it on bikes that have been neglected, but since more and more people are getting there share of ethanol fuels now, it is starting to be more common.

I would pull the carburetors, disassemble, inspect, clean (carb and choke cleaner only), and reassemble. Also check the condition of the petcock with a vacuum gauge at this time with a clear tube, check for fuel weeping through the diaphragm.

question, is there a "slight" stumble from idle to part throttle??? If so this would also tell you it's a fuel thing.

Think about how much air your bike is pulling in at idle.... almost nothing really, yet what it does get, still has to fall into the proper Air to Fuel ratios in order for it to fire and run properly. So adding any air (vacuum leak or clogged fuel port) or adding fuel (bad petcock diaphragm) at idle, is sure to cause problems.

Second guess...Not as likely, but still possible would be a charging issue, causing a weak electrical system at low rpm. But I've never heard of or seen this on a XX, so I doubt it, but I'm still throwing it out there.

I'm not worried about a mechanical mystery bearing issue etc., since it's.... actually the opposite of a load related issue. You said it dies when you pull the clutch in, removing the gear-case load.

...

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Doesn't happen as long as the clutch is in. If I pull

the clutch in any gear (including neutral) everything

is hunky dory at idle.

However, if I'm in neutral and I don't squeeze the

clutch, the motor will start to lug a bit. It will even

stall if the engine is cold.

Read it again, Eric.

You said it dies when you pull the clutch in, removing the gear-case load.
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Doesn't happen as long as the clutch is in. If I pull

the clutch in any gear (including neutral) everything

is hunky dory at idle.

However, if I'm in neutral and I don't squeeze the

clutch, the motor will start to lug a bit. It will even

stall if the engine is cold.

Read it again, Eric.

You said it dies when you pull the clutch in, removing the gear-case load.

:icon_redface: Ooops... I must have been having a dislexic read memory moment. :icon_rolleyes: Seems to happen more and more often the Older I get. :icon_biggrin: That and CRS.... happens all the time.

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