Cam chain rattle noise

[silentIm]

Today this morning I noticed my ninja is noisier than usual. Sounds like soft slapping noise that noticeable on lower RPM, that goes to higher pitch as RPM rise. It was louder when RPM goes down. Most noticeable when the engine is under load. I guess it was the cam chain has been stretched.

My mileage so far is 38.000 km (23.600+ miles) with the ninja. Is it the normal lifespan for the cam chain that I can expect? Is there anyway to extend the life of the chain? I read a local motorcycle magazine wrote that the tensioner bolt can be replaced with a longer one. Can this really be done?

Is there any guide I can refer to replace the cam chain? I will do this on a shop of my friend, as I dont have the tooling. He is kind enough to guide me when needed and lend me a space and tooling of his shop.

[ninjamunky85]

Are you certain it's the cam chain? Have you checked the valve clearance or done an adjustment lately?

Cam chain stretch is a known problem with these bikes. You can replace the stock automatic tensioner with a manual one. That will give you more adjustment, and allow you to get more life out of the chain.

[Scattcatt]

The life on your cam chain itself should still be good. The cam chain tensioners that come stock with the 250's occasionally fail to function properly, I've had this happen to two of them.

You can fix this problem by disassembling and cleaning them (there are several video guides on youtube available) or simply by going with a manual CCT as Ryan has stated. I chose the latter, I installed an APE manual CCT on my 2008 and have not heard a single tick come from the engine since.

[silentIm]

My last valve adjustment was like 6000 mile ago. So i am not sure either. But i plan to check it as well this weekend as i check the chain.

[silentIm]

All right, before I open all the engine, I check the tensioner first. here I have removed my tensioner. I tried to reset the tensioner, but it stuck. I tried to push it by weighting with my body but the pushrod wont retract back. Is my tensioner broken then? Or is there any trick I dont know about?

Here is the photo of my tensioner

[silentIm]

One more thing, do i need to top my camshaft first before i do it?

[alex.s]

it is not supposed to retract by pushing. if it did that it would be useless. you remove the bolt and use a screw driver to 'unscrew' it internally to retract it

don't turn the engine with the tensioner out. don't put the tensioner back in without knowing how to correctly put it in (retract it fully while it is being installed, then allow it to extend)

and yes, it was supposed to be at TDC when you removed the tensioner.

[silentIm]

Originally Posted by alex.s

it is not supposed to retract by pushing. if it did that it would be useless. you remove the bolt and use a screw driver to 'unscrew' it internally to retract it

don't turn the engine with the tensioner out. don't put the tensioner back in without knowing how to correctly put it in (retract it fully while it is being installed, then allow it to extend)

and yes, it was supposed to be at TDC when you removed the tensioner.

Alright, I see.. I saw a little gap inside the backside of the tensioner, when I turn it with small screwdriver the pushrod retracts.

And I have not turn the engine to TDC when I removed the tensioner. So I need to remove the left cover of the engine and turn the engine to TDC. Correct?

Before I started working on the ninja, I put the transmission in sixth, and I use the kickstand instead of paddock stand. I am sure the bike doesn't move. I don't feel any push from the tensioner when I removed it, so I think my timing chain has been stretched already.

[alex.s]

easy way to tell is to slide it back in without screws... if it goes all the way in fully extended without having to push on it, then yes your chain is totally stretched

[silentIm]

Originally Posted by alex.s

easy way to tell is to slide it back in without screws... if it goes all the way in fully extended without having to push on it, then yes your chain is totally stretched

Thanks a lot Alex. I did just what you said. The amount of push left from the tensioner is less than 1/4 inch. The rattle noise is gone.

I didn't crank the engine to TDC though, I was afraid without the tensioner the chain will miss a tooth with the camshaft. I shifted the transmission to sixth gear though before working, and I didn't jack the swing arm. Nothing is wrong after I put back the tensioner.

[headshrink]

I HIGHLY recommend getting a manually adjusted CCT. The Kawi automatic ones are crap. I've got to run to a meeting right now, but a search will yield a link to where to get one.

[Scattcatt]

Originally Posted by headshrink

I HIGHLY recommend getting a manually adjusted CCT. The Kawi automatic ones are crap. I've got to run to a meeting right now, but a search will yield a link to where to get one.

Ebay APE CCT

[silentIm]

Originally Posted by headshrink

I HIGHLY recommend getting a manually adjusted CCT. The Kawi automatic ones are crap. I've got to run to a meeting right now, but a search will yield a link to where to get one.

Originally Posted by Scattcatt

Ebay APE CCT

Thanks all the advice guys. Much appreciated. My stock CCT still working fine. Just need some lube filled into its orifices. So for this moment I am still using it. New cam chain is already in order.

I use aftermarket CDI that can raise rev limiter (BRT Imax super pro, advanced version from i-Dtis, programmable 24 steps, 50 ignition maps stored in memory), I guess that cause the chain life much shorter.

[mgentz]

Originally Posted by silentIm

Thanks all the advice guys. Much appreciated. My stock CCT still working fine. Just need some lube filled into its orifices. So for this moment I am still using it. New cam chain is already in order.

I use aftermarket CDI that can raise rev limiter (BRT Imax super pro, advanced version from i-Dtis, programmable 24 steps, 50 ignition maps stored in memory), I guess that cause the chain life much shorter.

Just know that you have to split the cases in order to replace the cam chain.

[headshrink]

Originally Posted by mgentz

Just know that you have to split the cases in order to replace the cam chain.

There is a way around this:
1) Break the chain
2) tie a wire to one end of the old chain, and one end of the new chain
3) manually turn over the engine and let the old chain pull the new chain around.

Easy peasy

[mgentz]

It can be done, but braking the chain will most likely put metal in the motor. Its not hard to split the cases just time consuming. Besides, based on your miles it might be worth a look.

[headshrink]

Originally Posted by mgentz

It can be done, but braking the chain will most likely put metal in the motor. Its not hard to split the cases just time consuming. Besides, based on your miles it might be worth a look.

I didn't consider that. You could still do it if you used a rag under the breaking site. This might avoid needing a gasket (assuming you need one there... I haven't looked).

[silentIm]

Yeah i need to split the crankcase.. It wont be a biggie though.. I consider it as quest for learning something new. i will post my progress in another thread soon as the chain arrive.

[headshrink]

Originally Posted by silentIm

Yeah i need to split the crankcase.. It wont be a biggie though.. I consider it as quest for learning something new. i will post my progress in another thread soon as the chain arrive.

There you go... making it an adventure is the way to be a life-long learner.