1937 ULH starting problem

[shinedogg]

Thank you Kitabel, I am tearing her apart this week. I will update what I find. Sounds like you've dealt with this before.

[duffeycycles]

I would do a leak test before tear down.I always question a compression test on a kick start bike.You did say kicks way too easy,but a Flathead does kick much easier than OHV because they were lower compression.I never start a bike with starting fluid..period...If you put your finger over the plug hole & kick ,do they both feel like they give a good pop?I would listen to Robbie's advice.If it started before,I question the fuel flow first.Is there fuel in the bowl?

[shinedogg]

I typically dont use starting fluid either (ethyr), but I had to test the timing to believe I wasnt losing it. Snap-on compression tester so its not some NAPA unreliable POS. 45 to 49 everytime, throttle open, light oil spray in plug holes aimed at the bore. I need to look at the top end for my piece of mind, measure pistons and cylinders. ring gap etc. Gotta do it. Thank you for your suggestions. I need to cross this off the list. Wont take me long and I'll know.
Thanks again.

[shinedogg]

Well I'm glad I did. .022" ring gap at the tops, .005" - .007" piston to cylinder. at the tops. Not whack out of tol. but worthy of a service. She'll be back together by this weekend and I'll give'r another shot.

[govmule84]

Well I'm glad I did. .022" ring gap at the tops, .005" - .007" piston to cylinder. at the tops. Not whack out of tol. but worthy of a service. She'll be back together by this weekend and I'll give'r another shot.

Attaboy. That will eliminate one variable.

[kitabel]

.022" is exactly .002" larger than factory new.
All pistons are smaller at the top.

[shinedogg]

Thanks Govmule84, that's right. Exactly Kitable, while I'm here, I'm installing the the 26373-41 and 26369-41 spring and adjuster in the pump to increase pressure. If I understand your book correctly, the pump needs the inlet and outlet ports modified to be larger, increasing the volume of oil to be pumped by the vanes. So installing one of the 4 vane rotors so readily available online would be useless, correct?

[kitabel]

Not necessary - helpful, and not known to what degree. It's something I do because I'm compulsive. I have no results w/r/t the 4 vane pump. The maximum pressure is limited to whatever the relief spring is set at.

[shinedogg]

I understand. I will play with this, I'll modify an early flatside that I have, record the pressure of the stock pump, put the new spring and adjuster in, record again, change to a 4 vane, record and finally install the modified pump with all the goodies. Sounds like a fun project, once I get this old girl running. I can't wait to retire so I can do this full time.
Thanks for the help.