Strange Noises =S

[deliriousthunder]

Bike is a 600n fyi..

I've had it for a few months and am used to the quirks; the clutch rattle and the vibrations at around 4000-4500rpm etc.. this is definately new..

I adjusted the chain recently (first time I have) and it started doing this.. I think it's maybe just coincidence, but thought I better mention it anyway..

So now when pulling away in first, when changing to second, and sometimes when simply going slow-ish (~20mph at a guess) it makes these clunking noises, almost like a hammer tapping something, and they are evenly spaced too, not sporadic.. The noises are accompanied by a 'feeling' of losing power to the wheel for a split second, it reminds me of when my chain used to slip on my mountain bike, though I don't see how that could be happening on the divvy, especially not with a set rythm like this..

I get the impression that the noises come from almost directly beneath where I sit, but slightly behind.. This is really difficult to be sure of though, what with my helmet on and the engine noise/other traffic to try and filter out..

I'm absolutely positive something is not right, and it's worrying me that I don't know what it is.. Any help appreciated..

Thanks,

[kruzer]

Just one comment: it is possible to get a better feel what/where is going on when you operate the bike on the center stand. If the noise comes at all in such type of operation, of course.

[bobh]

Could be a tight spot in the chain?

[suzukikidontheloose53]

Might be your rear sprocket bearing,try wobbling the rear sprocket

[cam7777]

Sounds like the chain is too tight.

Get someone of your similar weight to sit on the bike, off the stand of course, and then check the chain tension.

[m40man]

Aug 31, 2008 8:51:46 GMT @cam7777 said:

Sounds like the chain is too tight.

I agree - that would be my 1st check!

[CD]

I'd go with the chain and then the rear sproket bearings. The adjustment should be done on the tight spot so it wont go over-tight as the wheel turns. If the chain does have a tight area its most probably on its way out.

[deliriousthunder]

Thanks for the advice guys..

When I adjusted the chain I did it on the tight spot.. and the tightest spot currently has an inch of slack, more on the rest of the chain.. I don't see how it can be too tight with that much slack, but I took the advice anyway.. I sat on the bike and got a friend of mine to check it, he thought it was slack if anything..

The sprocket doesn't feel loose either..

I have noticed a small amount of oil around one of my spark plugs, literally a drop or 2, just enough that I could notice it when looking closely.. I don't really know much, so I'm loathe to make ignorant suggestions, but could it be a problem with a cylinder not firing sometimes?

EDIT: actually, I tried it on the centre stand, and it didn't seem to do it.. I'm assuming if a cylinder wasn't firing properly it would do it regardless of centre stand/on the road..

Help wish I had enough money to put it in to a garage

[darren]

what was meant by a tight spot, was a tight link in the chain, causing a clunk at a regular interval due to the link(s) not been slack enough to move around the teeth of the sprocket evenly, this causes a clunky noise

[53huntly]

Hi, i am new to this site but i think this post covers my problem, but my question is, how to i locate the tight spot and what play should there be on the chain. Thanks in advance

[General Gman]

If it's the sprocket carrier bearing, the sprocket probably won't feel loose - you need to take the wheel off and then have a good look at the sprocket carrier.

[CD]

With the bike on the centre stand the drive chain will be looser than when the bike is on its wheels. Turn the rear wheel and check the chain slack at every foot (or so) of chain. If any section is tighter, tension the chain (with rider sat on the bike) at that tight spot.

The rear wheel has three bearings. 2 in the wheel and one in the sprocket carrier. They are all standard sizes so cheap to replace and should all be done at the same time. I always use greased for life bearings with integral seals. Haynes give good instructions.

BTW - A chain with tight spots or siezed links is on its way out, so best be looking out for a replacement fairly soon.

[53huntly]

Thanks all, will do the checks and if necessary replace whats needed. Cheers.

[CD]

Another thought...

If the tight spot is looser than the remainder of the chain then you could be running the chain too loose causing it to flap about. Haynes manuals explain all this.

Put the bike on the centre stand and turn the wheel until the chain is at it's tightest point. Carefully, drop it off the stand and sit on the bike. The chain should have the correct amount of tension at this point. Adjust it as necessary without turning the wheel.

If there is a great deal of difference between the tight and loose areas of chain then you need a new chain and sprocket set. BTW don't bother with alloy rear sprockets. While you have the wheel off you can check the bearings.

[billywhizz]

Chain adjustment for the D6 is 30/40 mm(if i remember correctly). about 1 1/2 inches in english!
This is for the bike on centre stand, and a mid way point between sprokets.

yes first check for any tight spots, and the adjustment should be made at the tightest point.

It could look a bit loose after, but when off the stand, the chain tightens, then when you get on, it will tighten more, so shouldn't be adjusted when anybody sitting on it

The yamaha owners manuel, if still with the bike, also covers this as does Mr haynes

chain to tight will also affect gear changes

[CD]

I always set the tightest spot to 20/25mm with the rider on the bike because I otherwise find the chain can be easily set too tight. A little bit loose is much less harmful than a little bit tight.

[bear]

I also had this problem on my 125 when the chain was too loose. Exactly the same symptoms - "crunch" and momentary loss of power, more apparent at low speeds.

[CD]

Oh yes a loose chain will mess up gear changes - apart from risking it jumping the cogs and jamming the wheel. The other delight is when your split link breaks and the chain gets spat off the bike.
I was lucky - no damage, but it can smash engine cases and lock the wheel.