Very little compression

[bearholt]

I was just wondering if anyone out there could suggest why I suddenly have very little compression in my '54. I rode it into the shop (heated) last fall just fine. This spring I went to kick it over and could get no compression. I've checked the pushrods (twice, and left them looser than I normally like just to be sure they're closed) (solid lifters) and have visually watched all the valves moving and have looked at them with a borescope too. The top rings at least look fine (again with a borescope) and I've put oil into them 3 times now. After the last time I got one conpression kick but then it went away again, so then LOTS of oil the last time. I've left it for 2 weeks now to soak in good. Also I had a quart leak down from the tank during the winter but drained all of that from the cases. I can't figure this out. It's too coincidental to have happened to both cylinders. I took a compression reading and got an equal 30 lb. from both. The engine was a very tight rebuild but I've put on over 1000 miles on it since.
Thanks

Bear

[NightShift]

Dear Bear,
That IS diabolical! Can you put air pressure through the sparkplug holes and listen everywhere like the timing plug?

Sounds like a genuine X-files case to me,

[steve_wood]

Maybe the head bolts came loose??

[PanPal]

Clutch could be slipping too. You sure the motor is turning all the way over when your kicking.

[john HD]

what kind of rings did you use?

john

[bearholt]

Hi to all that answered my post. I had considered doing a full leakdown test next but then John, you peeked my curiosity and I thought I'd check my clutch. The engine was turning over OK but maybe slipping. I figured I try something and disconnected the clutch rod from the lever. Behold!! Compression and a start on the 5th kick! A little smoky from the oil I put in the cylinders but that was all. The 54 purrs again. Perhaps a clutch adjustment is in order...
Thanks to everyone that answered. Should have come to the forum 3 months ago Cheers
Bear

[bearholt]

Sorry that was PanPal that had the clutch idea. Thanks

[PanPal]

Sorry that was PanPal that had the clutch idea. Thanks

Well my name is John anyway. Good to hear you got it going!

[john HD]

my father in law (who was named john) once said

"all the good guys are named john"

john

[Henrik_K]

I'm in the same situation as you - with very little compression.

How would you know if the clutch is slipping? If I can see the main sprocket rotate when kicked - everything (in that department) must ok, or??

Thanks, Henrik

[john HD]

How would you know if the clutch is slipping?

easy, remove the primary cover. then place a chalk mark on the pressure plate and one on the clutch shell. make the marks so they line up. then kick the bike over about 5 times. if the marks remain lined up the clutch is holding and will probably handle top gear under acceleration.

if they do not remain lined up try one half turn on each of the nuts on the pressure plate and try again.

john