Timing is half a tooth out.

I am overhauling my XR because it burns oil. I noticed before I removed the cam chain that with the flywheel on the "t" mark ,The marks on the cam pulley do not line up. They are out by about half a tooth. There is no slack in the chain and it doesn't matter which direction I come up on the marks from.  Does this mean the chain is worn out ? Can I replace the chain without removing the sidecover ?

timing chain.jpeg  here is a picture

By the looks of your tensioner being below the top of its bracket, the chain and/or tensioner are beyond the service limit.  To check the chain, you need to wrap it all the way around the gear and then see how much it lifts up from the gear.  


The proper way, is to remove the side cover and clutch but I have seen it replaced by getting the pin out of the new chain and then tack welding it after assembly. 


To do it right, you need the service manual.

Edited by Baja Rambler

I can buy a chain with a "soft link"  my local bike shop says its easy to fit.

In that case, you can press a pin out of the old chain and wire it to the new chain then pull it on through.  You need to pull the tensioner up and pin it first.  

My personal choice would not be to use the soft link, instead to buy the gasket for the side cover and replace with an OEM chain. Inexpensive opportunity to have a look at my clutch and everything else on the lower end outer case.

Replace the tensioner while you are at it.

Replace the tensioner while you are at it.

Curious, what's your reasoning for that?

I am overhauling the engine because it burns oil. I recently had the side case off to check the oil screen and I don't want to do it again. The tensioner is fine and does not need replacing. I am fitting a new Wiseco piston kit and valve seals.

While Im here .. Do wiseco piston rings come pre gapped ?  I think it should be about  9 thou ?

If we knew the year and model, someone with a manual might look it up for you.

Its a 1995 XR250 R   wet sump model. I would appreciate it .

Curious, what's your reasoning for that?

XR250s are old bikes.  The material the tensioner and guide are made from would appear to me to be subject to brittleness and breakdown over time.  I would do it just to be safe, when I recently did the top end on my 03 I had that thought.  May be wrong, but I figured better safe than sorry since I was there anyway.  Around $110 for both from Discount Honda Parts.

Edited by cjjeepercreeper

On that basis, I could replace the whole bike. I'm pretty sure the tensioner is ok. My mate is a Honda importer and restorer . He is helping me rivet the timing chain . I will double check with him . I appreciate your oppinion and thanks anyway.  

Just to record.  I measured the new chain against the old one and its about half a link shorter.

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