1947 UL Woes, any flatheaders out there????

Greetings,

I have a 1947 UL (74" flathead, big-twin for you youngsters) that has been
giving me periodic problems.

If it has been sitting for a while (a few weeks or longer), when I kick it
over it has zero compression. At first, I thought it was the clutch
slipping, as after about 30 kicks or so, I would get compression and the
thing would fire and then act normally until I put it bed for a while. Just
a few weeks ago, I put a few hundred miles on it. In fact, once it starts,
if I ride it every other day or so, I do not have the zero compression
problem.

Well, I was thinking about riding the bike over to Daytona this weekend and
thought I would fire it up, get it warm and change the oil, so, I roll it
out of the garage, put in some fresh fuel, and sure as poop stinks, zero
compression again. But, this time, I take one of the plugs out and kick it
over, still no compression, but I have spark. So, the engine must be
turning over. Eventually, the compression comes back and it fires right up
and runs like a top.

So, what do I have? Sticking valves, lifters, hallucinations?

Have a beer on me.

CJ
==

A leakdown test will tell you real fast if it's valves. I'd guess some
carbon on a valve hanging it open just a little. Next time you get it
started reve it up a LITTLE, after it's warm, and mist some water into the
carb. A lot of times this will knock the carbon off.

Dale R

I'd say rings or valves either one . Next time , try putting a teaspoon of
oil in each cylinder . If that brings the compression up , it's probably the
rings . If not , it's probably the valves . Hmm , have somebody else kick it
over while you listen at the carb and tailpipe for leakage ...