Step 1 on a cafe build of an 82 KZ750M1

Looking for some feedback on how to kick off my cafe racer build. I posted a "hello" in the new members forum with a pic.

The motor in my bike looks very clean, but is not currently operational. It has likely sat for 20 years with only 9500 miles on it (poor thing ) It kicks over smooth, shifts ok, but my compression test only showed about 75 psi on both cylinders. I put a bit of oil in the plug holes and ran the test again with no change in the results. So, I suspect either a head gasket leak or valves are out of adjustment. No matter, my long term plan is a complete top end rebuild because chances are gaskets are shot, piston rings are cheap, and I honestly have never done one before and look forward to learning (I can hold my own turning a wrench and know just enough to be dangerous).

My searching on the following question has came up with no results thus far.

The question is, do I bother with the rebuild (along with carb rebuild) to get it running and tuned this fall before I do my cafe build over the winter (in Minnesota) or do I just see if I can get it started as is (maybe see if head bolts can be torqued a bit, valves adjusted, clean up the carbs good, new plugs. patch any wiring issues, etc) just to see if the motor has the potential and do the rebuild later in the winter so I can fire it up and ride it in the spring to break in the new rings properly without it sitting for several months without even starting?

Take the engine apart and see what the internals are like, you were going to rebuild the top end anyway so you won't have lost anything by taking it apart.

I'd patch it together and get it running if you can, before I got into the whole project.
Bill

I just don't want to get into a situation where I build a bike that has a hopeless motor nor rebuild a motor only to have it sit and wait to be run so long that it has lost some of that "rebuild" potential before it even sees the road.

Adjust the valves. The compression will most likely come up and keep increasing once it's running and the rings reseat.

Get it running and see how it runs for awhile. This helps to know what is a must do before your tear it apart.

Perfect, that will be my plan!

October = get it running and plan the build
November = Start looking for the "must have parts" and tear down
December = Fabrication and fitment
January = Painting and final fitment
February = Motor rebuild
March = hopefully out on the road by the end of the month? Too optimistic in MN, maybe :dry:

tv_cafewannabe wrote: I just don't want to get into a situation where I build a bike that has a hopeless motor nor rebuild a motor only to have it sit and wait to be run so long that it has lost some of that "rebuild" potential before it even sees the road.

I'm not sure what you mean by "rebuild potential". The new parts you install during the winter will still be essentially new in the spring.

It's been sitting for a long time so you'll want to tackle the carbs (and the valve adjustment, obvi) first. Do you have any info on why it was parked back then? With only 9500 miles there shouldn't be anything catastrophically wrong but better to find out sooner than later.

Something else to consider: if you're planning to use a bike shop for any machining and/or fab work, you might want to start the engine rebuild before February. Other people may be getting bikes ready for spring and you could end up on a waiting list. December might be a good time for such things: most people will probably be focused on the holidays.