new rebuilt KZ750 Engine... SMOKING!??

OK I got the bike all rebuilt. and she started right up!
BUT... The engine is smoking a gray/white smoke.

I put on 4 air pods, and a breather filter on the beather case. stock exaust... for now.

What could cause the smoking? both pips are smoking.

Update! Here is a pic of the KZ750 complete!

Maybe still some assembly lubricants or the rings haven't seated yet . The motor looks fantastic , what type of finish have you done ?

Post edited by: hannah1, at: 2008/01/01 23:01

Un-combusted oil in exhaust is associated with light coloured smoke.

Could be a valve guide. More likely a bad valve guide seal leaking... if so seals are an easy and cheap fix.

Best of success!

PS
Great looking bike.

Post edited by: bill_wilcox100, at: 2008/01/01 23:36

I had this problem with an old MGB, years ago. It had a vacumn operated pcv valve and the diaphragm had a hole in it and it was sucking oil from the crank case. I'm not familiar with your system but maybe something like that could be a possibility?

That is a cool looking seat. It's not stock, is it? Where did you get it?

Did you install pistons and rings dry or lube cylinder walls? If you lubed (I do) give it a chance to burn off.

may need to run it for a bit, you can put a fan in front of the motor and run the rpm up and down to break it in

do not worry about pre-break in smoking. get 15-20 minutes on the engine varing the revs not over revving it. change the oil and filter. ride it around like normal .

I had an engine that I re ringed and it took almost 100 miles to quit smoking. the glaze took a bit to scuff off maybe a little synthetic oil,wrong crosshatch angle ??? . I dunno why it took so long to break in. but it eventually did- I knew I had the ring end gaps right and piston to cylinder clearance was correct, so I ran it

Smoking is pretty common on a fresh engine. Break it in and it should stop. DO NOT baby the engine. Run it hard. If you baby it, it will smoke and the rings will not seat properly.

baldy110 wrote:

Smoking is pretty common on a fresh engine. Break it in and it should stop. DO NOT baby the engine. Run it hard. If you baby it, it will smoke and the rings will not seat properly.

3rd gear , 10 pulls from 30% of redline to redline . That's what my engine builder always said , he built me several fast , long lasting roadrace engines .

UPDATE! Thanks for your help! .

OK so the engine has stop smoking after riding for about 20 miles. YAAAAAA!

As for the engine paint, I used a aluminum paint for engines.

It only took 3 1/2 weeks to rebuild! So you can do it too!