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Discussion Starter #1
Hello, I have this fairly bad ticking/rattling sound coming from my quad when she is running and it gets faster as I rev higher. I’m pretty sure it’s either my timing chain or the valves just need adjusted but is there anyway to know for sure without pulling things apart?
 

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Does you have a tensioner for the timing chain? if so you could adjust your tensioner so it tightens up your timing chain. Hope this helps!
 

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Well, I am not sure for your model. But on a fourtrax 300, this it. So look at some diagrams for your specific model. I think it more than likely has a tensioner for the timing chain.
Screenshot 2021-02-20 195119.jpg
 

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I think it would be your timing chain if you machine has lots of hours. So did you buy it new? Has it been rode had? Does it have lots of hours? And if it has lots of hours, it's very possible that your valves need to be adjusted. Also what year is it?
 

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Discussion Starter #7
I didn’t buy it new it probably has a couple owners before me, it’s 1999 and has a lot of hours I would say. I have to replace the clutch plates so when I take off the front engine cover I will have a look and see if it is the timing chain. Can you put in a manual timing chain adjuster?
 

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Download the service manual from my signature block below
and check parts links at Rocky Mountain atv and Partzilla

yes very well could be a timing chain.Or needs valve adjustment A shop could diagnose it and do the work for you. Might run $400-$600 US. Unfortunately most Honda shops markup jobs for these older quads. Still, might be worth it if it’s otherwise well running machine

With older machines you can check to see if your cam chain tensioner is fully extended by measuring the depth your automatic tensioner will go.

Review the service manual for tensioner removal.
If you remove the tensioner, you can use a small screwdriver to lock the tensioner so it’s fully extended. Insert the fully extended tensioner back into the engine. If you can nearly fully insert it, then your cam chain is too loose.
 

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Discussion Starter #9
That is perfect I will check for that, will my quad definitely have a timing chain adjuster and if so where is it located because I had a look and I can not find it
 

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Discussion Starter #10
I was just on another page and one boy couldn’t locate his tensioner, and another person told him it could be totally enclosed behind the front cover and you may have to remove the clutch to get at it.
 

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Your model might have different config.

here’s a pic that prob applies only to older engines.

see the gap from the tensioner base to the jug? In this case larger gap means tensioner has sufficient travel remaining
151511
 

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Since it has high hours, I would bet money it's a timing chain. Be careful you don't run it too long, I think yours is an ''interference'' engine. This simply means that if you timing chain snaps, or jumps off the cam gear, the valves will become out of time and hit the piston. The valve(s), will bend, and put a nice big gouge in the top of your piston. This of course would cost even more money, so If I were you, I would replace the timing chain, and while down that far do a top end rebuild. But it's entirely possible your timing chain is tight, and you just need a valve adjustment. The only way to know for sure is take it apart. Good luck!
 

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Your welcome, I was glad to be helpful for you, please let us know if you have any other questions! Also is your quad a ''recon'' or a ''250ex''?
 
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