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Flathead Power Questions

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42Flathead80

Posts: 12

Joined: Tue Mar 30, 2010 10:04 pm

Post Sat Apr 03, 2010 4:47 pm

Flathead Power Questions

Howdy, I am new to this board, and kinda new to Flatheads, even though I have owned four since 1972. I took them apart to keep them from being stolen, and someone stole everything but the engines (37, 39, 40 & 42). A year ago I bought a new 2009 Night Train with Stage 1, and it was stolen with only 614 miles on it. It was an awakening to dealer and insurance company rip-offs. I decided to build my own, since I had built many old Pans (choppers). I also decided to convert the sucker to electric start, which I did. I used the 42 UL engine with ULH cams.

I am 99.9% finished with it, and I am in the process of cranking it, but ran into some cranking issues. I am charging the battery right now. She has 5-gal fat bobs, Jackhammer grips, drag bars, high risers, turn signals, horn, neat fringe seat, short bar, belt primary (BDL), Mikuni 34 mm carb, chain rear, cat-eye dash, disc brakes front and rear, completely rebuilt engine (by me), aluminum heads, centrifugal advance ignition, and all in a swing arm 91 Chevy S-10 Seafoam Green Paugho frame. Fitting all the parts that weren't made to fit was a long tedious job, but worth it.

My questions are concerning the power I may expect. Will she hit 120 mph? Will she hang with the late models? Is overheating the problem I have heard it to be?

I will post pictures once I crank and ride her.

Jim
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RUBONE

Posts: 380

Joined: Fri Nov 30, 2007 7:24 pm

Post Sat Apr 03, 2010 5:18 pm

Re: Flathead Power Questions

My questions are concerning the power I may expect. Will she hit 120 mph? Will she hang with the late models? Is overheating the problem I have heard it to be?

Will she hit 120. Only if you drop it from a plane! Not even realistic on a standard UL. And ULH cams are the same as UL cams, only the bore size is different.
Will she hang with the late models? NO, and if you push it that hard it will die an early death.
Is overheating the problem I have heard it to be? It is if you try to keep up with the late models!
A standard UL engine makes roughly half as much power as a stock shovel, less than half of a standard Evo, and about a third of a big TC with injection. It is an old engine with technology that was outdated before it was built. Why try to make it what it isn't and just try to enjoy it for what it is?
Robbie
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42Flathead80

Posts: 12

Joined: Tue Mar 30, 2010 10:04 pm

Post Sat Apr 03, 2010 8:04 pm

Re: Flathead Power Questions

Well, that is unfortunate, meaning being on the downside of power. Still, I was planning on using one of the other engines for a stroker job. Why do it? Why not? I started this project to be a little on the side of different, and it had been a ride for sure, from making the drive side bearings and seal combo to fitting that BDL belt drive in that 65 inner primary with tin cover. That inner primary is a lot lighter now, but I am content.

Thanks for the input, you told me what I wanted to know. I just got tired of seeing those engines setting on the shelf with no chance at life.

Jim
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panic

Post Sat Apr 03, 2010 9:49 pm

Re: Flathead Power Questions

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Last edited by panic on Sun Nov 28, 2010 12:18 pm, edited 1 time in total.
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42Flathead80

Posts: 12

Joined: Tue Mar 30, 2010 10:04 pm

Post Sun Apr 04, 2010 9:07 am

I know

He told me exactly what I wanted to know. I always knew they were light on HP, but I have never seen one running. I am an old Panhead guy. I have owned 10 or more Pans, but took a career break. Now that I am too old to do anything that requires tons of energy, I decided it was time to return to my roots. It has been interesting, if not entertaining at times. Now I can't crank the bit*h, and it is fuel/timing check time. I am charging the battery right now for the forthcoming test of nerves and will. :twisted:

How do you like your stroker? I would love to see pictures of it. I have taken a liking to the old iron, as that 2009 Night Train satisfied my need for speed. I took a 100+ mph ride every morning while I had it. Not the best break in procedure for sure. Whoever stole it may have engine issues down the road! :mrgreen:

Thanks again, guys. I hope this board satisfies my future need for answers. I have a question already. Does it make a difference which connection on the coil to which I hook the distributor and hot wire? I know it is a waste system, and I am running a generator and points, but I am not a genius when it comes to electrics. :oops:

Jim
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Frankenstein

User avatar

Posts: 1547

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Tue Apr 06, 2010 6:30 pm

Re: Flathead Power Questions

Welcome to flatheads, here is a 84 inch I built 2 years ago.It pulls very nicely, used T&O torque monsters. I use the 38 Mikuni VM and like it, simple and effective, my flatties are one kick starters warm, one or two cold, started one all winter at least once a week. (kept in an unheated barn here in upstate NY, using 20-50)
DD
Image
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SPYDER

Posts: 20

Joined: Fri Feb 20, 2009 3:29 pm

Post Wed Apr 07, 2010 4:10 pm

Re: Flathead Power Questions

See Paul Freibus at American Cycle Fab in Bloomsburg Pa [570-752-8715] for a re-grind on your stock cams.Should help the mid range you're looking for.
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panic

Post Wed Apr 07, 2010 9:07 pm

Re: Flathead Power Questions

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Last edited by panic on Sun Nov 28, 2010 12:18 pm, edited 1 time in total.
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jib

Posts: 570

Joined: Sat Dec 10, 2005 3:36 pm

Location: devon,england

Post Thu Apr 08, 2010 1:55 pm

Re: Flathead Power Questions

looking good dr dick, do you have some complete bike photos.

regards jib
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years
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Frankenstein

User avatar

Posts: 1547

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Fri Apr 09, 2010 7:43 am

Re: Flathead Power Questions

Hey jib,
here's a link to the website:
http://dicky_linn.webs.com/46ulchopper.htm
It was built to be a tractor motor, no cams, or breathing mods, just more compression and displacement. And the combustion chamber does have "pop up"now. And it does have LOW end grunt..
enjoy,
DD
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jib

Posts: 570

Joined: Sat Dec 10, 2005 3:36 pm

Location: devon,england

Post Fri Apr 09, 2010 12:09 pm

Re: Flathead Power Questions

thanks dr dick, great pics of cool bikes and very interesting tech,an all in excellent site.
regards jib
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years
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42Flathead80

Posts: 12

Joined: Tue Mar 30, 2010 10:04 pm

Post Tue Apr 13, 2010 7:23 pm

Re: Flathead Power Questions

Very nice flattie. Thanks for the photos and the response.

Jim
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dalaymond

Posts: 304

Joined: Mon Oct 25, 2004 12:01 am

Location: Jonesville, Louisiana, USA

Post Mon Oct 11, 2010 12:35 pm

Re: Flathead Power Questions

Good looking scooter.

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