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View Full Version : OT Yamaha 650 cam chain tool



gkman11
04-20-2005, 07:19 AM
Been playing with an '81 650 XS vertical twin this winter.Tires, chain and sprokets, electrical, misc. Though I was ready for spring when the head gasket gave up at an oil passage. Per Clymer manual and mikesxs.net the overhead cam chain has to be broken to get the head off and doesn't have a masterlink and the replacement has to be rivited on with a special tool (about $40.00). Any easier softer way?

topct
04-20-2005, 08:38 AM
It's been a while since Iv'e worked on one of those but I don't recall having to break the chain. I think all you do is unbolt the cam chain sprocket and pull the cam out of the head. The chain then just kinda hangs there and the head can come off.

Hang the chain up with a piece of wire. This will help rethreading it back up throught the head.

One other thing. When you pull the head, make sure you keep track of any shuffle pins (hollow dowels) and any of the other seals they might use (should be with head gasket set).

What your talking about is when you might want to replace the chain without pulling the head and splitting the crankcase. If you decide to replace the chain, make sure you keep track of both ends of it when you cut it. If you loose it down into the engine you will have to take the crankcase apart to rethread it around the crank.

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Gene

[This message has been edited by topct (edited 04-20-2005).]

[This message has been edited by topct (edited 04-20-2005).]

precisionworks
04-20-2005, 08:39 AM
The chain breaker-riveter tools are about $50 and up. I've never seen a high-speed chain that uses a master link, as they are nowhere nearly as secure as riveted.

Looks like an easy home shop project to build one. http://altura.speedera.net/ccimg.catalogcity.com/210000/210900/210963/products/5743388.jpg

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Barry Milton

Michael Moore
04-20-2005, 09:28 AM
The riveter is just a little press, so you could make a pointy die block and squeeze it with a vise grip. The ends of the rivet master link pins should have a little dimple in the end to locate the die and make them spread easier.

cheers,
Michael

topct
04-20-2005, 09:47 AM
I may have been mistaken about unbolting the cam sproket. It may be it, and the cam are one piece. If so, you may have to back off or remove the tensioner to give you enough slack to pull the chain up and off the sprocket.

Sorry about the confusion, it's been awhile.

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Gene

gkman11
04-20-2005, 11:33 AM
Thank you. Thank you.

Topct, hope you are right. Would sure like to avoid breaking the chain for a simple gasket job.

Otherwise it sounds like a HSM project to me too just didn't know what it looked like. Made a chain breaker for the rear drive chain already. Think I'll order a couple of extra links to test the riviter on.
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Wonder what the point angle should be? Any thing else you can think of?

topct
04-20-2005, 12:04 PM
Triple check the timing before you button it up. There are timing marks for this. And rotate the engine by hand a couple of times. There is no room for any error.

Make double sure you get all the dowels and seals back in where they belong.

Don't reuse any seals that go in there.

Do get a top end gasket set and replace "all" the gaskets.

Do not use any gasket cement or coating on the head gasket. It needs to float somewhat.

Do use gasket cement everywhere else. I recomend Either Yamabond (Yamaha dealer) or another version, a product called Threebond liquid gasket #1104.

Good luck,



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Gene

ACF
04-20-2005, 08:41 PM
The old Hondas had the spocket bolted to the cam and things worked as topct said.
Don't know about your machine though.

Chris

J. Randall
04-20-2005, 11:38 PM
I put a new cam chain in a 70 model that had broke, and I don't remember having to get a special tool. I think the replacement back then had a masterlink, but maybe that has changed. I had a 72 later that I didn't break in right and glazed the rings. I had the head and jug off of it later and ringed it and ground the valves and I don't remember having to break the chain, and it was low enough mileage I know I didn't replace the chain. James