Jump to content

Installing manual cam chain tensioner XT350

Recommended Posts

I have developed suddenly a rattling in the engine that when I listened through a piece of hose, sounds like it's coming from the cam chain. I'm going to try and swap the stock automatic tensioner for a manual one.  I figured this would be the cheap and easy thing to try first.  The bike only has 4K miles on it, but from what I could find on the subject, the stock tensioners are a time bomb on these bikes. Anyone ever done this on an XT 350?  I'm having trouble finding any info on this procedure, about this specific bike. I'd appreciate any tips or advice.  Thanks

Share this post


Link to post
Share on other sites

They are a time bomb. Mine went at appx 10,000 miles. Fortunately, it was at start up and only bent a valve. I have not found a manual tensioner though a few companies have offered to have me mail my automatic one in and they could see if they match it to a manual one already being produced. I've not done that yet.

The 'rattle' I had sounded like a worn valve rocker, more of a tick than a typical cam chain 'cofve can of washers'

Share this post


Link to post
Share on other sites

I found a manual tensioner on eBay for $25.  I guess it's just important to keep some tension on the chain, so it won't slip a tooth? Can I access the chain from the timing cover or do I have to take the head off?

Share this post


Link to post
Share on other sites
33 minutes ago, scotty27 said:

I found a manual tensioner on eBay for $25.  I guess it's just important to keep some tension on the chain, so it won't slip a tooth? Can I access the chain from the timing cover or do I have to take the head off?

Do you have a link to the part?

Installation is simple.

Remove the fuel tank, remove the spark plug. Remove the valve cover

Rotate the engine until the intake and exhaust cams are pointing at 2 and 10 O'Clock, meaning neither one is pressing down on the buckets. Wiggle the chain up and down to get asn idea of proper tension.

Remove the center bolt from the tensioner, remove the spring. Remove the two mounting bolts., remove the tensioner.

Be sure the new manual tensioner, is fully retracted, install it. Then with your fingers, extend the adjuster until you first feel resistance. Wiggle the chain and set the final adjustment of the tensioner when it feels the same as the oem one did. Tighten the locknut.

Reinstall the valve cover and spark plug. Reinstall teh fuel tank.

Run the bike until hot. At idle, loosen the locknut and tighten a little with your fingers. Then try to loosen it with your fingers, noting where it was before you do this. As you slowly loosen, you will suddenly hear the 'coffee can of washers sound'. Then tighten until it just will go away. There will still be some noise. It will not go away. If you make it so tight that it does go away, it will be over tightened and cause excessive wear and cause a lot of problems. Once adjusted, it will probably never have to be adjusted again unless a new cam chain is installed..

Share this post


Link to post
Share on other sites

You gotta be extra super careful setting up a manual tensioner.  Set it up what looks like perfect when the engine is cold and you get a chain to tight when the engine warms up.

  • Like 1

Share this post


Link to post
Share on other sites
On 7/16/2017 at 11:38 PM, Eatmore Mudd said:

You gotta be extra super careful setting up a manual tensioner.  Set it up what looks like perfect when the engine is cold and you get a chain to tight when the engine warms up.

Every installed one? 

Share this post


Link to post
Share on other sites
On 7/16/2017 at 11:38 PM, Eatmore Mudd said:

You gotta be extra super careful setting up a manual tensioner.  Set it up what looks like perfect when the engine is cold and you get a chain to tight when the engine warms up.

I would think it would be the other way around, too loose at temp?

Share this post


Link to post
Share on other sites
7 minutes ago, Shackleton said:

I would think it would be the other way around, too loose at temp?

Consider valve clearances.  When hot and cold specs are given the cold spec is looser.  I think the dimension to consider is the thermal expansion of the engine between the crank and cam, it gets a little taller between cold and operating temp.

  • Like 1

Share this post


Link to post
Share on other sites
Consider valve clearances.  When hot and cold specs are given the cold spec is looser.  I think the dimension to consider is the thermal expansion of the engine between the crank and cam, it gets a little taller between cold and operating temp.

Could you correlate this to cam chain tension adjustment?

Share this post


Link to post
Share on other sites

You need to set the chain for proper clearance when hot, which will be slightly looser than it will be cold. 

I'm not a big fan of manual tensioners.  It is quite possible to set the tension incorrectly and cause engine damage.  If the stock tensioners really are that bad I guess it makes sense to convert it to a manual tensioner but you have to make sure it is set correctly.

  • Like 1

Share this post


Link to post
Share on other sites
On 8/3/2018 at 1:26 PM, Shackleton said:

I would think it would be the other way around, too loose at temp?

The engine expands in all directions when heat is applied. 

If you want to measure how much the cylinder elongates, mic it at room temperature then mic it again after soaking it at 325* F in the oven for an hour.

Share this post


Link to post
Share on other sites
8 hours ago, Eatmore Mudd said:

The engine expands in all directions when heat is applied. 

If you want to measure how much the cylinder elongates, mic it at room temperature then mic it again after soaking it at 325* F in the oven for an hour.

That a joke? 

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

Reply with:


×