Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties Foot Shift Conversion

Foot Shift Conversion

Moderators: Curt!, Pa

Post Fri Mar 04, 2011 6:00 pm

Posts: 766
Location: CA USA
Spyder,
If you could repop the B & H shifter for the WL I'd be interested in one, pre-47. 'dog

Post Fri Mar 04, 2011 7:08 pm

Posts: 693
Location: somerset, oh usa
Having never seen one for a 45" hands on, I'm doubting that many parts other than possibly the cover are the same.
Having said whatever that, just offering any dimensions/drawings/pics of one for a 74 (early shift pattern, i believe)
I'm missing the mousetrap spring and the clutch perch and lever, should anyone have any spares.
And if you're going to make one for a 45", I'd be interested also.

Post Fri Mar 04, 2011 7:39 pm

Posts: 387
The 45 unit is almost the same as the big twin one. There is a special bracket to hold the mousetrap and the main shaft of the shifter unit has notches indexed differently. Very similar in construction! The stamped cover is the same and is probably the single most expensive piece to duplicate!
Robbie

Post Sat Mar 05, 2011 3:39 am

Posts: 1634
I don't see any reason why any 45 should need a mousetrap. Big Twins don't really need them, as the later "mousetrap eliminator" showed. There isn't a great deal of room on the front down-tube on a 45 and the single tube means there isn't much lateral clearance either.

In any case the action is smoother and the take-up easier without one.
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Sat Mar 05, 2011 10:10 am

Posts: 387
Whether a 45 needs a mousetrap or not is a personal decision for sure. However, all B&H kits for 45 came with their mousetrap.It has a special bracket to place it outboard of the tank in the same location as a big twin. And when H-D big twins deleted it they added another friction plate and softer springs to compensate. And as to it being easier or smoother without one having used many of both over the years I don't agree. A properly set-up mousetrap is a joy to use!
Robbie

Post Sun Mar 06, 2011 6:29 am

Posts: 1634
it's amazing what you can find on youtube.. home-made ratchet shifter for flathead Big Twin

http://www.youtube.com/watch?v=qmPrZufc ... re=related

seems to work pretty well
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Sun Mar 06, 2011 1:24 pm

Posts: 304
Location: Jonesville, Louisiana, USA
Spyder, I too would be interested in a repop B&H foot shift/hand clutch setup for a 45. I think they're pretty cool.

I saw one on a 45 back in the early 90s. It had a mousetrap on it. It seemed to shift pretty well.

Post Sun Mar 06, 2011 2:01 pm

Posts: 188
Location: sweden
B&H documents on the "Beauty of speed", shows the specific 45 parts.
http://beautyofspeed.com/data/doc_b&h_f ... /index.htm

Post Tue Mar 08, 2011 9:50 pm

Posts: 2684
Location: Los Angeles, CA
This factory racer has a hand clutch and foot shift. I like the double down tube frame too.
Image

Post Tue Mar 08, 2011 9:58 pm

Posts: 975
Location: Markt Einersheim, Germany

Chris.

Is there any way to get a larger/closeup view of the footshifter on that bike?

George

Post Wed Mar 09, 2011 1:57 am

Posts: 1634
I tried right-click on the image and "save image", then open the resulting file and increase the percentage. At 400% the definition is breaking down, but I'm fairly sure that it is simply a foot lever bolted onto a cut-down clutch pedal. Don't forget that a flat-track racer would only make two changes, both within the first twenty or thirty metres before entering the first turn, and then spend the rest of the race in top gear; so the rider would probably accept a lot of sloppiness if he was beating the handshifters.

I'm more interested in the double down-tube frame. I've always thought the 45 frame was an exercise in incorporating as much weight as possible without actually providing any strength in the process, and I was surprised to find fairly recently that the Big Twin frame was much the same weight.

The rigid BT frame is a much better design, quite state-of-the-art when it was designed and as good a rigid frame as was made anywhere. It's a great shame that the 45 wasn't provided with a similar frame at the same time.
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Thu Mar 10, 2011 10:36 am

Posts: 228
Location: Burlington Iowa USA
I believe the B&H mousetrap was more to increase the travel of the clutch release arm so the clutch would break Free. A hand lever alone barely makes it.

Post Thu Mar 10, 2011 5:54 pm

Posts: 693
Location: somerset, oh usa
There is no mousetrap on that racer that i can see and it is not a positive stop shifting mechanism by appearance although I'm not disputing the post immediately above.
I've had contact with the builder of the one on youtube and it was worked out through trial and error by drawings and mockup in the land of OZ.
Slightly modified to use a production balance spring.
Made for his own use on his machine and claims it works very well.
Does anyone know if they in fact made reversed mechanisms for early versus late or was the shift pattern just backward depending on the model year where applied?
Thanks.

Post Thu Mar 10, 2011 7:31 pm

Posts: 1634
hotrods1 wrote:
I believe the B&H mousetrap was more to increase the travel of the clutch release arm so the clutch would break Free. A hand lever alone barely makes it.


there's a thread about this somewhere. The auxiliary clutch kit supplied on WLAs in the UK is pretty poor. The geometry of the lever and actuating arm doesn't provide sufficient lift, but this can be improved by redrilling the arm to provide more travel - the cable hole needs moving closer to the pivot so that the same cable travel provides more angular movenet at the arm and hence, more lift on the release pushrod.
Shoot, a man could have a good weekend in Dallas with all that stuff...

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