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heads for stroked flatheads

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45Brit

Posts: 1399

Joined: Tue Nov 27, 2007 2:29 am

Post Sat Apr 02, 2011 12:14 pm

Re: heads for stroked flatheads

interesting stuff.

re Albion boxes and clutches, they were often used with JAP engines in the 50s ( partly because there was a fashion around that time for using the Royal Enfield swing-arm frame for grass-track bikes, a very light and strong frame by the standards of the day ). Strong but heavy, and largely superseded by the lighter and more robust AMC units in the 60s.

I suspect the slipping issues are related to different styles of track preparation and generally very different machinery. Speedway bikes are extremely light by the standards of US machines, it is common to have a clutch adjusted almost at the point of slipping; the theory is that if your front wheel is JUST off the ground as you leave the line, you are transmitting all the power you can use. Given that even a 50s speedway JAP will only weigh 88kg or so ( modern bikes a re restricted to a minimum weight of 77kg ) and speedway tyres are a trials-type with a lot more grip than a US flat-track tyre ( especially the 22" ones used in the 50s ) then this is necessary.

Track preparation differs, too. US style "blue groove" tracks are not seen, it is usual to dress the track with fresh shale for every meeting and grade the track several times in the course of the meeting. A track curator allowing a US style "blue groove" to develop would be considered hopelessly negligent! Having a clutch which breaks away at a crucial point so that if you find some grip, you have a buffer between you and abruptly looping the loop is both safer and faster.
Shoot, a man could have a good weekend in Dallas with all that stuff...
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Frankenstein

User avatar

Posts: 1539

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Sat Apr 02, 2011 8:49 pm

Re: heads for stroked flatheads

great looking heads Bruce! Now, for the 80's :lol: :lol: Just an open note to let you know the Cam lobes I got from you are installed and working great. It took about 2 hrs to degree in the first lobe, and about 1/2 hr for the next ones. Had a buddy do the tack welding of the lobes in place, only took a couple of minutes.
I hope to make Oley this year, we'll see what toy I bring down. Never been before, hope to meet a few webboard members as well.
DD
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Pa

Site Admin

Posts: 4649

Joined: Sun Mar 12, 2000 1:01 am

Location: Ohio USA

Post Sat Apr 02, 2011 9:08 pm

Re: heads for stroked flatheads

Doc....I'll get there ifin you be there. been wantin to shake your hand for over 10 years now. :D
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Frankenstein

User avatar

Posts: 1539

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Sat Apr 02, 2011 9:13 pm

Re: heads for stroked flatheads

Well, seeing as I'm "retired" now, I should have more say as to when I go galavantin' around the country. Retired meaning my day job messing around with electrons got so slow, I signed up for SS, and took a part time job fixin "metric" bikes. Whatever is the world coming to???
DD
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37ULH

Posts: 682

Joined: Mon Nov 25, 2002 1:01 am

Location: somerset, oh usa

Post Sat Apr 02, 2011 10:27 pm

Re: heads for stroked flatheads

I wish that I had pictures but I know of an Ariel with a complete K engine in it that I've been watching and waiting for more than a few years. He spotted a cylinder at a scrap yard and dug around til he found the rest of the it and grafted it into the ariel.
If I recall he had to lenthen the frame but was nicely done.
He also has a 49WL that I hope to own someday.
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