Vandepol
XS650 Member
Complete rebuild of 1977 engine. Rephased, third over on pistons. Trying to adjust the cam chain tensioner. When I get the proper adjustment, the tube is sticking out to far for cap to completely seal. Any advice!
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Cam chain adjustment
- Thread starter Vandepol
- Start date
Mine did exactly the same thing. I had only the big acorn nut. I found and added the lock nut under the acorn nut like found on the 81 models. Worked fine. One would think if it came off that way it should go back. Nope. Evidently the new chain is a lot tighter than the ones used back then. I don't know but but adding the lock nut worked. Your looking for "Nut, Special 90179-18274. this worked on my 77 standard.
Vandepol
XS650 Member
Thanks, I thought about something similar, of just filling it up with washers and an o-ring. Maybe once it breaks in it will get back to normal.
I've got about 1500 miles on mine but haven't tried the cap nut without the special nut to see.
E-bay different # but same installation on partszilla. I have an 81 engine I borrowed mine off of. take a look.
https://www.ebay.com/i/273870590445...1291&msclkid=a5201f906bd512f20ecc415b995578a6
E-bay different # but same installation on partszilla. I have an 81 engine I borrowed mine off of. take a look.
https://www.ebay.com/i/273870590445...1291&msclkid=a5201f906bd512f20ecc415b995578a6
But in your case, "normal" really isn't that good. Yamaha used several different tensioner assemblies over the years. All had a locknut to lock the adjustment in place before fitting the cover nut except your type D assembly. On yours, the acorn cover nut was meant to act as the locknut. But, as you tighten it down, there's no way to stop it from possibly tightening your adjuster more. Yamaha realized the error in their ways and came out with the revised type E assembly, putting the locknut back on there. The best thing you can do is update yours to this later type E. Details are here, post #22 .....
http://www.xs650.com/threads/cam-chain-tensioners.1056/page-2
http://www.xs650.com/threads/cam-chain-tensioners.1056/page-2
Vandepol
XS650 Member
That is what I will do. Thanks for info. This is my first build, so am learning a lot.
Vandepol
XS650 Member
Vandepol
XS650 Member
What is the part number, best place to get one?
I don't think you can buy any of the parts new anymore except for maybe the copper sealing washer for the locknut. Search eBay. Complete type E assemblies can usually be found for about $20 or less. I've bought several already. Since the type E is nothing more than a revised type D, most of the parts are the same. The housings are the same so you can get away with just swapping in the type E plunger and locknut. But, you very rarely find those parts sold individually, hence the need to buy an assembly. Still, around $20 is a small price to pay for what I consider a much needed upgrade.
