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cylinder relieving U-series

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don

Posts: 554

Joined: Fri Oct 01, 1999 12:01 am

Location: Spokane WA USA

Post Tue Oct 05, 1999 4:15 pm

cylinder relieving U-series

it appears that 80" stock cylinders prior to
1938 were factory relieved, ported, and polished. at least the '36 & '37 sets i've seen are identicle reliefs.
why did the factory stop!

in viewing NOS '37 cylinder set it appears that the relief was cast in, since bore surface and relief have no machining marks yet,
and indeed the intake & not the exhaust chamber are ported but not polished.
[This message has been edited by don (edited 06 October 1999).]

[This message has been edited by don (edited 16 October 1999).]

[This message has been edited by don (edited 22 October 1999).]
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dotman

Posts: 582

Joined: Fri Oct 01, 1999 12:01 am

Location: meridian, id. usa

Post Fri Oct 22, 1999 5:15 pm

Is it just that the VL s where ported and relieved by d pig farm and the UL s where done by owners ? The VLs exhaust port on the front cylinder comes out at a straighter angle while the UL is folded inward so the exh pipe has clearance from the frame downtube. did the VL in 36 get put into the knuck frame or did it retain the single loop frame until the U took its place in 37?

[This message has been edited by dotman (edited 22 October 1999).]
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don

Posts: 554

Joined: Fri Oct 01, 1999 12:01 am

Location: Spokane WA USA

Post Fri Oct 22, 1999 6:26 pm

recieved this e-mail reply;
120-37 and 120-371 are 1937 to 1941 BT 80" sidevalve cylinders if they are ported,
and 1937 and 1938 BT 74" cylinders if they are not,they also differed in bore 3 5/16" for 74" and 3 716" for 80".
120-38 and 120-381 are 74" only cylinders from 1939 to 1948 and as such were never ported from the factory.
120-362 and 120-363 are the new 9 bolt cylinders that were used on 1936 74" and 80" VL's. I am under the impression that they came both ways like the '37 and '38 UL/ULH cylinders althought the only difference in the 74" and 80" VL motors is the stroke unlike the UL's which changed the bore.
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don

Posts: 554

Joined: Fri Oct 01, 1999 12:01 am

Location: Spokane WA USA

Post Fri Oct 22, 1999 7:30 pm

indeed the 120-362 front exhaust outlet angle
is at the north northeast and downward, while 120-37&-38 are north by northwest and slightly lower than the horizontal plane.
120-363 rear outlet is more inward and down compared to 120-371 which is upward and away from center line in comparison.
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1937hd45

Posts: 233

Joined: Thu Oct 14, 1999 12:01 am

Location: Ridgefield,Ct 06877

Post Fri Oct 22, 1999 8:18 pm

Ok, this is new stuff to me. Where is due north in relationship to a motorcycle, and is it different if you're in Australia?
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dotman

Posts: 582

Joined: Fri Oct 01, 1999 12:01 am

Location: meridian, id. usa

Post Fri Oct 22, 1999 9:03 pm

According to the crystal ball, if one throws salt over the left shoulder and the wind is blowing up your right pant leg north would be behind you, however if the wind is getting your leg wet because your going against the grain then el norte is the other way around unless you are standing on one legg in which case its to your good side unless your bad side happens to be facing east except in australia where only god knows fer sure

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