kz440 overbore sizes and other ?'s

[samsquantch]

Hi there, I'm very likely going to end up with a kz440 project that hasn't run in a while. It has 19k on the clock. The owner hasn't been into the motor, so we don't know if it's been overbored or anything yet.

The only rings I can find are .5mm over. Is that the first over? Assuming the pistons are stock size, can I get away just honing, not boring and throw in the .5mm over rings?

Any other tips for sourcing/swapping piston or rings for a kz440? Aren't the 400's the same dia? Would that work? What about cb360's or something like that?

Thanks

 

[Nebr_Rex]

Wiseco 810 kit,KZ750/4 pistons
69mm = 463cc
Shallower dome,remove base gasket and use 1194.
That will get you 9/1,9.2/1 is stock. 8)

 

[AlphaDogChoppers]

Is there a reason why you are tearing the engine down?

 

[samsquantch]

It's leaking oil from one of the gaskets. It'll at least need that. I'm hoping to just make/buy some new gaskets and button it back up without doing anything else, but I wanted to learn more as a contingency plan.

Plan A= new gaskets, adjust valves, button up and check compression- go from there.

 

[AlphaDogChoppers]

I would run it first, check compression, fix gasket.

 

[samsquantch]

Thanks for the help. You're saying to let the leak go and get a baseline on the motor as is? I'll get the valves set first. Then, plan the repair based on that? Definitely gaskets, hopefully nothing further.

Sounds like a good idea to me...

Thanks again.

 

[AlphaDogChoppers]

One of the most common mistakes of newbies, IMO, is the first thing they do is tear down the engine without even having an idea of its condition. It will read low on compression if it has been sitting around a while, so it should be run a bit, then you will know more about it's condition. Probably won't even need to re-ring it unless the gasket work needed makes you pull the jugs, in which case you might as well re-ring.

You can go ahead and use those oversize rings even if you don't rebore. You will have to set the ring end gap. Not a difficult job, but it is one you could screw up if you don't do it properly.

 

[samsquantch]

Great info- thanks Alpha, Swivel, and Rex!

 

[Shermanator86]

Sign up here at the kawi twin owners forum- http://www.armbell.com/forum/index.php?sid=eb994ade8c5f8e1e47485e5f6af0b93a&mforum=kz400
, might take awhile to get a response but they were a big help in my rebuild