Topic: So, I have a smoking problem...

[Scott S]

 Well, I don't, but my '78 550K does.

 When I picked up the bike I knew it was smoking from the #1 pipe/cylinder. All of the plugs seem rich or dark, but not oil fouled. It sat it my garage for a while and seemed to stop smoking, but during a recent tuning session the smoke from #1 returned.

 This bike isn't on the road yet and I started a tune-up (adjusted valves and cam chain, started synching carbs but ran into a petcock problem. I'll be pulling the tank and carbs for a good cleaning, then finish the tuneup.) Anyway...

 I feel...and hope...that it's just a valve stem guide. If I can borrow a leak down tester and compression tester, will I be able to determine if it's a guide or a piston/ring problem?
 I'd hate to pull the head to do a valve job/guides and reinstall it only to find out that I have a broken ring or worn cylinder.

 Might be a good excuse for an overbore, huh? 

[TwoTired]

My 78 Cb550K smoked, too.  Sometimes worse than others.  Usually the hotter it is the worse it is.
I reasoned the thing ran hot and hardened the valve guide seals.  I figured out a way to replace those without taking off the head, and did.
But, during the adventure, I noticed the exhaust valves wobble in the guides a lot more than the intakes do.  So, I don't think the new guide seals are going to last very long.  I've been putting off the job for a while now, replacing the time with 22.5 house projects.
I guess the head has to come off after all.  I didn't really want to do that, as it's the only 550 I have where the oil doesn't weep out the sides.
My MC shop friend says he has the tools and will advise and watch me replace them in his shop.  Says, it's no fun and fairly easy to break them during installation.  Then there is grinding/lapping the valves.

Wah.

Hard to believe a bike that runs so well must be torn down that far and needs so much work.


Wah, sniff. 

I'd rather fly airplanes.

[KingCustomCycles.com]

Fly airplanes?  Model or full scale?  Which one?

[TwoTired]

Fly airplanes?  Model or full scale?  Which one?

I still own a Grumman Tiger.  Not clear if the FAA will still let *me* fly it. Medical issues.  Two PEs and no primary site found.  They like to know both cause and cure.
Lately, I've been on an R/C airplane binge.

[KingCustomCycles.com]

Very cool TT.  My last personal plane before getting out of the headaches was a 1947, 108-1 Stinson.  Flew to Oshkosh 26 years in a row and used to teach for EAA on weekends.  I still fly some RC and am the "Unmanned" guy at Purdue.  Have flown UAS for agricultural research for 8 years.  I got tired of the Stinson costing me a nicely restored K0 about once a year :-)  Thread hijack complete.........

[Scott S]

 Now back to out regularly scheduled thread....

 Anyone?

[dave500]

if you pulling the head the barrel just slips off,you can look at the pistons and rings then and make a call,,nothing like a rebored motor though.