HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
Thermos O flask

Timing Chain Worn?

10 posts in this topic

I have just fitted a hotcams decompression cam into my '00 wr400.

The cam dots and crank dots lined up fine but when i released the tensioner the crank timing line moves a bit off, like 5mm.I tried moving the cams a tooth to see if that was better but it was WAY OUT then so i moved it back again,engine turns over fine but i havent started it yet.Could it be timing chain stretch? Its like a 1/4 of a crank tooth out(1 crank tooth =2 cam teeth)The bike has done about 3,000km and i always used full syn oil every 5,00km.What is the life of a timing chain? Are the chains known to stretch?...nervous.:applause:

Share this post


Link to post
Share on other sites

I cannot answer your question about if your timing chain is stretched. But, they do stretch. When they do, the cam timing changes. Most engines end up with retarded cam timing when the chain stretches. This often moves the torque curve up in the RPM range a little bit.

Chris

Share this post


Link to post
Share on other sites

Sounds like the T chain is stretched. Probly never been replaced. If you can put in a camshaft you wont have any problem replacing the T chain. Do you have a manuel?

Share this post


Link to post
Share on other sites

My '99 is on its 3rd timing chain (4th maybe?). They stretch and should be replaced as a part of regular annual/biannual maintenance.

Share this post


Link to post
Share on other sites

I never thought they were that bad! Mate, its the original chain!

but it started ok and sounds good.Think i'll get me manual out and look into that one.:applause:

Share this post


Link to post
Share on other sites

I had one catastrophic failure related to the timing chain back in '03, if my memory serves. I had just adjusted the valves and when I was reassembling, I thought "that chain looks a little loose". Not much, but a little. I figured it was ok. 500 miles later, the cam chain slipped a tooth on the intake cam and I bent a valve. The worst part was that I was on vacation in the north GA mountains and that ended the trip for me. Now, I replace the chain regularly. Total cost of replacement (if done carefully) is less than 50 bucks in parts and a couple of hours of your time. A new chain and a new left side cover gasket is all you need.

Share this post


Link to post
Share on other sites
I had one catastrophic failure related to the timing chain back in '03, if my memory serves. I had just adjusted the valves and when I was reassembling, I thought "that chain looks a little loose". Not much, but a little. I figured it was ok. 500 miles later, the cam chain slipped a tooth on the intake cam and I bent a valve. The worst part was that I was on vacation in the north GA mountains and that ended the trip for me. Now, I replace the chain regularly. Total cost of replacement (if done carefully) is less than 50 bucks in parts and a couple of hours of your time. A new chain and a new left side cover gasket is all you need.

Rich - Can the cam chain be changed without undoing the head? Seemed to me there's not enough room and the chain is not quite flexible enough to bend around the crank shaft to remove (or install) from the top with only the valve cover and cams removed.

Share this post


Link to post
Share on other sites
Rich - Can the cam chain be changed without undoing the head? Seemed to me there's not enough room and the chain is not quite flexible enough to bend around the crank shaft to remove (or install) from the top with only the valve cover and cams removed.

It can be done. I've done it more than once. It's tricky (actually, it's a pain in the ass) but it can be done. The chain isn't the issue, it's the chain guide (opposite the chain tensioner.) You have to unbolt the chain tensioner then work the guide loose to allow the chain to slip in and out of place. You don't really have to bend the chain. Just let it fall to the bottom of the motor and you can remove it. Put the new one on the same way in reverse. I use an extension magnet to grab the chain to pull it up to the top.

If you go the "easy" way, you have to drain the coolant and take off the head and cylinder. And the cost is higher because you would need new head and base gaskets in addition to the parts I mentioned above. Taking off the head is more straightforward but it is more work.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0