pulling away noise

[el_oso]

So the thundercat has started making 'noises' when pulling away. It happened a month or so back for a day then went away. I've noticed it has been back intermittently the past couple of days. I've checked the standard sort of stuff. Chain adjustment is good, no tight spots. Both the chain and sprockets are relatively new, maybe two months old.

The noise sounds a little bit like when you don't give a diesel any revs and try and pull away fast; that kind of I'm going to stall if you don't give me more fuel sound. It only happens when I pull away. I've tried high gear low speed acceleration and I can't hear it then. It also doesn't feel like there are any extra/abnormal vibrations, it's just a horrible sound almost every time I pull away. Also haven't noticed a loss in power/acceleration.

Any chance this is not a front sprocket/drive bearing failure?
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[MartQ]

What sort of noises?

Does the noise change with road speed or with engine speed?

[el_oso]

[MartQ]

While you're at it, have a quick check of rear wheel bearings and gearbox output shaft bearings.

Also check for binding brakes and even loose engine mountings.

[Walloper]

'The noise a Diesel makes when you don't give it enough revs'

Oh that makes it much clearer now.

You may mean the noise made by Pre-Ignition of the air-Fuel mixture.

This causes what is called 'Knock' (Pinking).

It is caused by the fuel igniting too early in the four stroke cycle. Or more exactly before the spark ignites the fuel at the correct time.

It can be bad timing. Fouled spark plugs. Fouled Valves. Bad fuel mixture.

How many miles on bike?
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[el_oso]

Would knocking not occur Out of gear and also at all rev ranges though?
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[Walloper]

[el_oso]

Thanks. Now that I am at work and my code is compliling I'll have a re-read of engine kocking. If I get time I'll have a look at the plugs on new years day. Knocking usually happens with a lean mixtre right? So I'll be looking for white plugs
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[Walloper]

[G]

I've got a feeling the TRX may have suffered with insufficient clutch lubrication when pulling away - so other Yamahas of that time may have as well.
The GSXR1000 K6 certainly did - there was a mod you could do to drill a couple of holes in the clutch basket so oil could get inside.

However, this was more of a dry scraping sort of rattle.

[el_oso]

So I had the bike up on the paddock stand yesterday, changed the oil and changed the plugs. While on the paddock stand I fired it up and went through the gears. They are a little bit smoother but still reasonably stiff. Shifting through them but the wheel spins with quite a lot of force in gear with the clutch in. Stopping the rear wheel with the brake will stall the bike if it's still in gear. There is also quite a bit of a lurch going from neutral into 1st/2nd. Never really noticed while sitting on the bike, but when it's off the floor it is very noticeable.
The cable is adjusted well and there is a very clear biting point when the clutch actually starts to grip.

What next? To me the clutch isn't fully disengaging the input/output shafts.

EDIT: I think that the gears are equally crunchy with/without the engine running but can't confirm.
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[G]

Remember cold oil will be considerably more viscous and so may be dragging the clutch around even if the plates are separate.
Could always try adjusting the clutch, anyway.

[Copycat73]

don`t suppose the clutch release bearing could have anything to do wit it ?
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Whatever I post I have no citation and no intention of providing one..
caveat emptor

[Walloper]

[el_oso]

the chain is newish (couple of months) and is lubed with engine oil at least weekly.

All wheel bearings were replaced at the same time as the chain and sprockets and are still fine (on the back at least).