Board index Flathead Power-Technical Questions, Answers, and Suggestions Big Twin Flatties 74" UH piston sources??

74" UH piston sources??

Post Mon Feb 20, 2006 10:31 pm

Posts: 3
Location: Wingdale, NY
I talked to my longtime mechanic today about rebuilding the ULH basket motor with 74" jugs I bought two weeks ago. Alas, he "can't be bothered with the old stuff anymore." His showroom must have 40 brand-new Victory and American Ironhorse motorcycles. So he's more a retailer now I hate to say. During the half-hour or so I was trying to persuade him to change his mind, he did mention that the toughest part about doing flatties in his experience was finding quality pistons.
What do you big-twin SV guys use?
I'll try to be more brief from now on, but I'm new here and I always get nervous around strangers.
'39 Knuckle
'39 UL(h)

Post Tue Feb 21, 2006 12:41 am

Posts: 304
Location: oklahoma usa
Pistons pop up at times on eBay. You might give Chuck a call at KickStart Motorcycle parts in Wyoming, Michigan at 616-245-8991. I've bought several sets of BT SV pistons from him with no problems. 5 bucks for a booklet and a real good guy to deal with.

The problem you suffer seems to be pretty common anymore. More and more dealers have adopted the attitude "20 years old, go away". It's all sales, chrome goodies, and T-shirts.

Post Tue Feb 21, 2006 11:08 am

Posts: 2688
Location: Los Angeles, CA
The dealers around here won't even work on Evo's anymore.

Post Wed Feb 22, 2006 2:41 am
I've always used the Eastern Parts strutted pistons, probably made in Japan in the 1980s, and never had problems. Well, except self-inflicted ones from leaving inadequate clearance. The VL pistons are the same as the ULH. Several dealers carry these, from standard to about +0.090 oversize. The only difficulty is they are made to a standard bore of 3 7/16", rather than the actual VL standard bore of 3.422", and thus come out 0.0155" larger than you expect from reading the old Harley manuals.

Post Wed Feb 22, 2006 8:18 am

Posts: 349
Location: Champaign-Urbana, IL
FHP continues to advertise "fitted pistons" with their 74" flathead cylinders. What are they using?

Post Sat Mar 11, 2006 11:34 pm

Posts: 4
I have a 1938 UL that I have bored out from stock to 70k over. There are several places here in the USA that you can purchase what you need. I have had Chevy Corvar pistons in my bike that worked just fine.
JP Cycles Vintage Catalog- 1-800-397-4844
Kick-Start Motorscycle Parts Inc.- 616-245-8991
Good luck!
By the way maybe you can help me. I am looking for a cam cover for my UL. As far I know no after market manufacturer or supplier makes or carries this cam cover. If you know of one in good shape, I would like to buy it .

Return to Big Twin Flatties