300ex timing chain

[sgc]

Son's 300ex had bored .60 over, timing chain keeps jumping off, took chain tensioner out and used tool to make it go in and out.

Reinstalled per manual by adjusting tensioner fully pulled in, then bolted on and released.

ex ran great for a three days, short rides around street yard.

Is the timing chain streched and needs replaced

[dork]

replace the chain, its a wear item and has a limited life span. also, check the tensioner by taking it out and pushing on the end of it with your palm. it shouldn't retract when you do that. FST sells a heavy duty chain.

[exman]

sounds like chain

1. check tensioner that is moves out freely and locks in place.

2. install it, release tension

3. engine tdc

4. pinch the chain at top of timming chain gear, and pull up,,,,any movement and ya need a new one

5. go with stock chain,,,unless the heavy duty one is cheaper

6. hint....check the micro or call honda and ask them what some of there dirt bike chain lengths(number of links) are.

7. example heavy duty chain for a 400 ex from atv places 80 to 90 bucks.....stock 400ex chain 80 -90 bucks....crf 450 chain 36.75 and its the same as heavy duty....just an example of 400ex ...be supri=sed what you can find when you research