cb900F cam shafts in 1980 cb750K?

[surfish95747]

Hey guys, I want to put some cb900 cams into my machine. I am thinking of buying these used ones off ebay to throw in my bike. They are from a 1982 cb900F. Will these just drop in and can I use the existing cam chaine, tensioner etc? I will be ripping into the engine to do a big bore 823cc piston kit start of next year, so I want to upgrade the cams as well. What do you guys think?

[shinyribs]

They will go right in. You'll have to check your valve lash, so you might end up buying shims, but that's all.

The bolt holes in the cam retaining caps ( what you valve cover bolts go in to ) are notorious for stripping. So go at it with caution. If they do strip, no big deal. A full kit from Helicoil will run about $40-60 and will enough inserts and all the tools required to fix every cam cap. Probably not needed, just a FYI. Retighten them with care and you'll probably be fine.

Even though you dont NEED to change the chain and tensioners out to fit the cams, they may be dead just due to age. Chains are cheap. SOHC chains are like $30-40, not sure about DOHC chains, and it uses two. But the FSM has specs in it to measure chains to see if they are stretched or healthy. The tensioners have plastic bits that are just getting weak due to age. Not a bad idea to swap them out just for good measure. If you build that fresh 823 then lose a tensioner/bind up a chain....

[surfish95747]

Hey shiny if you know where to find cheaper cam chains etc, let me know. I have been looking and everything is like 80 to 100 dollars! Thanks!

[shinyribs]

That's the curse of the mighty twin cam. More expensive parts! DOHC chains are massive compared to SOHC. I've never shopped for DOHC,only SOHC. But if I run across a deal I'll holler.

[Rodgil]

The best price I could find (last year) for my DOHC cam chains, was from David Silver Spares UK

[TOOLS1]

Unlike the SOHC engines roller chain, the DOHC engine uses a "Hy-Vo" (sp) chain. This type of chain is supposed to be a lot stronger then the roller chain. Do they really need to be changed as soon as the roller chain? I was under the impression that is was the tensioners in the DOHC engine that were prone to failure.
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