Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties Big flat into a 45 frame

Big flat into a 45 frame

Moderators: Curt!, Pa

Post Mon Feb 18, 2013 11:06 pm

Posts: 53
Anyone ever put a UL -80 cube into a 45 frame ???

Post Tue Feb 19, 2013 8:37 am

Posts: 111
Yes

Post Wed Feb 20, 2013 6:34 pm

Posts: 53
Was it worth it cost /labor how did it perform ? Did you go to a 4 speed tranny also ? Pushing my luck here but any pictures ? Thanks FRank

Post Thu Feb 21, 2013 2:07 am

Posts: 1654
I don't really follow the logic of this swap. The 45 transmission is its weak point and it isn't as though the 45" frame was ever regarded as a particularly good unit; it's heavy, and not particularly strong, needing additional bracing around the chain stays.

HD never used the design again, after all.

Chouts are different http://choutbreeders.blogspot.com/
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Thu Feb 21, 2013 11:02 am
Pa Site Admin

Posts: 5807
Location: Ohio USA

45Brit wrote:
I don't really follow the logic of this swap. The 45 transmission is its weak point and it isn't as though the 45" frame was ever regarded as a particularly good unit; it's heavy, and not particularly strong, needing additional bracing around the chain stays.

HD never used the design again, after all.

Chouts are different http://choutbreeders.blogspot.com/


HD used that designed 45 frame from the early pre 41 two bolt transmission frame design up through the 1941-1952 Solo model frame and beyond through the 1973 Servicar frame. That is a lot of years to use the same geometric frame design. The only real difference between the Solo and Servicar frames was the rear section of the frame.

Post Thu Feb 21, 2013 11:06 pm

Posts: 1654
well, yes, but it was basically the same bike. The Big Twins used a completely different frame design. The Servicars are/were directly derived from the WL and kept in production long after their commercial life was over, through government contracts - BSA kept the M21 60cc single in production for the AA contract after discontinuing dealership supplies, and Triumph never even attempted to sell the TRW through dealers.

No other bike ever used a WL-style frame and transmission, whereas the Panhead/Shovelhead swing-arm frame is a direct derivative of the original 1936 Knucklehead frame, and the K series and Sportsters use a frame which follows a direct line of development.
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Fri Feb 22, 2013 7:52 am

Posts: 303
Location: wooster oh usa
if you really want a big flattie in a single downtube frame look at a vl frame. stronger and more room for the engine.

Post Fri Feb 22, 2013 9:02 am
Pa Site Admin

Posts: 5807
Location: Ohio USA

barry wrote:
if you really want a big flattie in a single downtube frame look at a vl frame. stronger and more room for the engine.


Thanks for noting the VL frame Barry. I thought of it after logging off last night.

Post Sat Feb 23, 2013 2:07 am

Posts: 1654
There's a thread about a UL engine in a 45 frame in here dating from 2005
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Sun Feb 24, 2013 1:45 am

Posts: 1654
Been trying to access the old thread about this, can't access te pictures
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Tue Feb 26, 2013 9:42 pm

Posts: 497
Location: Six miles East of Cheney, Wa.
That's funny I was wondering why someone hadn't put a big flat in one of the new-wave 45 frames that take the big twin tranny. I personally prefer a bike that's a bit longer, has double down tubes, and is not short and stubby, but I guess it would have some "wow" factor or hot rod appeal for those that like that sort of thing.

Shouldn't be hard to do with some welding and el-heato-bendo. Or not. :roll:


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