valve job: "tensioner shaft stopper tool"?

Hey guys, time to do a valve job on the CRF. The owners manual talks about making a "tensioner shaft stopper tool". From the picture it looks like a key, and you use it to back the cam shaft tensioner all the way out and hold it in place while pulling cam assembly off.

Is this necessary? Or do you guys just use a screwdriver or something similiar? Does somebody make this aftermarket? This is my first valve job, so I'm hoping some of you guys out there with more experience can point me in the right direction.

Ride on...

cant use a screwdriver because once you back it out, it needs to lock into the housing...if you pull the cap off the tensioner you'll see what I mean...

just make it out of some scrap sheet metal or whatever you have lying around...also, i've heard of people having problems when they remove the assembly instead of backing out the I wouldn't try that either..

just look in the Honda manual, there is a very nice drawing of the tool with measures and all the info you need.

cant use a screwdriver because once you back it out, it needs to lock into the housing...if you pull the cap off the tensioner you'll see what I mean...

Yes, you can just use a small screwdriver and clamp a pair of vise-grips on the shaft and rest it against the case.

I made one for my 450 out of a stubby Craftsman screwdriver like the book says, and it works great, but it didn't fit the 250 so I used the screwdriver and vise-grip method.

I used a long skinny screwdriver and just duct taped it to the frame.

I made mine out of a coffee can. Just snipped it out in about 2 minutes and now it there to use any time with out any other hassle. You'll twist it in the hole but its spring loaded so you need to keep it from spinning back when you let go. Thats why the key is nice, twist it out and then push the key in so it holds in place.

Here's the one I made.


Why dont you just remove the whole thing :thumbsup:

Because you will just force the tensioner back in fully extended. That would put excessive force on the cam chain and maybe stretch it.

I just used an old feeler gauge and trimmed to size.

I removed the whole thing, and then after I was done I re-installed it. Next, I turned the screw until it had retracted the tensioner thing all the way. When you let go of the screwdriver it automatically rachets until it hits the cam chain. Then it is not actually fully ratcheted, in, just enough to tension the chain the way I understand it, it can never back off, but it can get tighter.

I just used an old feeler gauge and trimmed to size.

Me Too :thumbsup:

ok so after avoiding this tool the last 3 times I needed it...i have decided to make one. I looked in the manual and it calls out the dimensions but says..."the piece can be made from a thin piece of steel" 8mm 03/04 and 10mm 02...

I dont know about you but 8mm(roughly 5/16 inches) or 10mm(roughly .39 inches) thick steel is not thin! Is this a typo? When I think thin, I think 20 gage...

im thinking of using 14 gage (.0747 inches)which is 4 and a quarter times thinner then what they call out...

Is there some serious torque applied to this tool or something that im not seeing? 4 gage (.224 inches) will be the biggest I will use on this but then I fear it wont fit in the slot its supposed to fit into...

Definately a typo!

I believe it's .8mm for 02/03 and 1.0mm for 04.

I think I made mine out of a .020" piece of steel. I could be wrong though, it's been a while.

that blows...since I didnt get a response I had one run...5/16" precision ground...


I was looking in the manual and it shows the picture of it being used and its almost the size of the guys thumb...but there is no profile view to see how thick it is...

Damn that thing is HUGE! :devil:

It looks good though. :thumbsup:

You could still use it. Just mill it down to the proper thickness, or throw it on a CNC surface grinder for a couple hours. :awww:

thats to spec per the manual...+/- .0005...nothin like an EDM machine at my disposal!

We have a few Agie EDM machines here at work. Not to mention a ton of conventional mills & lathes, CNC mills/lathes/machining centers, 5 axis machining centers and a couple grinding machines to make custom tooling.

Hey, I like the looks of your tensioner tool, but it is way too thick. The 2002 specs call for 0.8mm, which is 0.031 inch. I used a piece of 22 gauge for mine. It is holding the cam shaft chain tensioner open right now while I find a dealer with the right size shims.

I would release the tension while you wait for shims.

Ok, thanks for the recommendation. I'll go take the tension off now.

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