A forum for owners of Yamaha TTR250 trail and enduro bikes!

the-dirty-commuter · Veteran Member

cam chain noise

TTRfan · Super Guru

Hi Oliver

Firstly check to see if the cam chain is worn. This means taking the tank off followed by the cam cover.

Turn the engine to TDC (single timing mark not the double one!) and see how the timing marks on the cam sprockets line up with the head.

There is a photo at the end of this article showing what I mean.

If the timing chain is good and you are still concerned then pop the tensioner out and check its action. I hope it's OK because new ones are quite expensive - see here

If you need any help just ask again wink

Cheers

Brian

PS This would be a good opportunity to check valve clearances as that is another cause of cam noise.

pug · Guru

Brian Oly was round my place earlier had me ear to his bike he was a little panicky thinking small end but 99% sure it's not. motor has under 5000 miles on it close to same as my bike miles. but his chain make's a lot more noise than my chain but have heard worse bikes running my Honda XL / XR for one I was thinking tensioner mite be a little sticky and not taking up what it should will see what he says after he has pulled it out. I use to make manual tensioners for racing bikes as one offs so will knock him out one if it's tits' up.

Pug

TTRfan · Super Guru

5,000 miles is a bit early for replacing a cam chain. Also, I have only ever come across one non-functioning tensioner on a TTR and I am pretty sure that was because the owner had messed around with it

I will be interested to see what Olly finds......

hanzo · Senior Member

Hey Pug I reckon you should knock up a couple of em there seems to have been a few threads recently about cam tensioners assuming thats what you ment about knocking one out hmm biggrin biggrin

pug · Guru

If I end up making some it will be 2-3 as it's as easy too do as making one it's the setting up of the mill and lathe that take the time for each cut so you mite as well work on 2-3 an take them through each re-set as one. so would end up with extra's well maybe one as I would have to holed one back for myself just in case I need one................

Pug

the-dirty-commuter · Veteran Member

I checked the automatic tensioner, no problems there. I'll get the cover of and check the timing marks tomorrow. Thanks for your help, I'll keep you posted.
Thanks

the-dirty-commuter · Veteran Member

Cam chain shows no wear, all lined up perfectly. Please can you give me a link to a thread for checking valve clearances? I can't find one!

TTRfan · Super Guru

Try here

the-dirty-commuter · Veteran Member

Hang on I'm an idiot! The cam sprocket lines are in line with the head but the flywheel mark is about 4mm past the mark in the hole. I think I'll be in touch for a new chain soon Brian!

TTRfan · Super Guru

If the cam sprocket lines are good but the timing not at TDC then it suggests that when you removed the tensioner the chain jumped a tooth or two on both sprockets.

Easily solved. Put the engine to TDC (single not double line), remove the tensioner again and rotate the camshafts to their correct position.

Brian

the-dirty-commuter · Veteran Member

Ahhh! That figures. Just as well I haven't tried starting it! I'm pleased I don't have to fit a new one before the weekend too! I will check the valve clearances tomorrow eve. Thanks for the link.

TTRfan · Super Guru

Didn't think to say but always put the engine at TDC and have the cam cover off before removing the tensioner so that you can see what's going on in there.

Otherwise, if the camshafts are in a position where they are holding valves open they are under a bit of pressure and will try and turn.

We haven't explained the noise though unless its the valve clearances.

Brian

the-dirty-commuter · Veteran Member

All working sweetly now. The noise was a loose spark plug. I wish I had checked it sooner! Thank you for all of your help, I've learnt a lot anyway!

TTRfan · Super Guru

Glad you found the cause of the noise Olly - nice cheap fix wink

Also thanks for letting us know. Quite often owners ask for help, which is freely given, and we don't get to know if the advice helped and what the fix turned out to be

Brian

pug · Guru

Ok Oly I will slap you for that Saturday seem to remember it as take the tank off when you get home tap knock and play with everything around the motor as it sounds like something is lose lesson learned Mate time to get them new tires in the mud trip to Dandy lane then the bike wash and down to the coast taking in the View point it is then see you Saturday will email you later in the week mate with start time

Pug

the-dirty-commuter · Veteran Member

Yes, you did say that! I thought i checked everything, only when I went to remove the plug did I realise how obvious it was! I'm a numpty who deserves a slap! I look forward to Saturday. Thanks

Markvan · Guru

With the cam chain rattle. Would it increase or decrease as the engine heats up. Im trying to pinpoint a noise on my 40,000 km ttr. Thanks.

pug · Guru

Would think it would increase as the chain heats up an gets longer but the whole motor is stretching out.

Pug

TTRfan · Super Guru

It could be that as the oil gets hotter and thinner any mechanical noise increases in volume and becomes more obvious.

Hard to describe the noise but, in my experience, a worn timing chain makes more of whooshing noise than a rattle.

One thing I have found is that if you set the exhaust valve clearances to the higher values of the range then they can really sing! I now set my exhaust valve clearances toward the bottom of the range.

If my reasoning is correct, as the valves wear into the head over time, the valve clearances will close up but I think the range of clearances given by Mr Yamaha provides a good safety blanket wink

Brian

olarf · Member

I think is is the right thread to keep the timing chain noise issues. I test ride ours yesterday a bit longer to see what difference the lowering link make handling related. WIll report this on a better place, in short words its pretty much fine.
Now my noise issue:
When driving I hear a kind of chain rattle in the partial load range. When I pull the clutch, the noise is gone, when I accelerate it is also gone. Only at partial load / unload comes this rattle. I think it can only be the timing chain or the chain tensioner. Can anyone confirm this thweoriw / behaves the noise so or can it be something else, the primary chain for example if there is one at all :)

mossproof · Super Guru

If you have a lowering link, it is quite possibly the drive chain slapping the upper roller. It took me ages to find this out. Try taking the roller off and test riding before you go into engine surgery!

ttr250.activeboard.com/t64893391/chain-roller/

The drive chain has some unusual harmonic waves under different loads, and the lowering link (or incorrect sag settings) puts the chain closer to the frame and roller. I am experimenting with a cush drive rear hub to see if this makes a difference...

olarf · Member

Thanks for that hint mossproof, will check that in Details, it could make sense as we never heard it before. Will delete the upper roller and check if it disappear / change then. As I plan to change the sprocket and chainwheel from 13/44 to 13/48 or 52 I guess it will change again but if it is realy the drive chain its good / less work and critical anyway.

olarf · Member

@ mossproof, you was sooo right. My upper roller was super weard out and therfore it could produce some funny and scary rattle noise. I checked my chan tension and delete the upper roller and the sound is gone :) You made my day and I definitly owe you a beer! So good to have a great community arround a bike, its helps a mountain.
Now I just have to find a creative solution to keep the upper roller but make it rattle free. As mine was mounted with a wrong screw and so ratteling already by itself, i guess I will find a way to mount it better and maybe a bit higher. Maybe an elyptic part can help to adjust it. I will think and try and post it.
Thanks and have a great week

Olaf

mossproof · Super Guru

Great news!

If (as I think) the roller is there to protect the frame from the chain, you could remove the shock and put the swingarm in it's highest position then pull the chain tight and you will see how close the chain gets to the frame. Then position the roller a bit lower to take the impact.

I like the idea of an elyptic bracket that will give a range of movement for adjustment.

I have also considered making the roller out of a softer material so the noise is not as bad.
Just wait 'till the plastic roller breaks up and falls off when you are on the highway at speed. The chain starts hitting the bearings and you think the engine has blown up!!

Cheers,

Simon.