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Thread: 37 ULH Carb/Throttle Mismatch?

  1. #11
    Join Date
    Aug 2004
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    Beautiful Northern New Mexico
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    What "manual" are you looking at Bob? The -53 part number throttle used from '54 up is totally different. So is the '48 and earlier one. You need the '49 type throttle information to make sense of it.
    Robbie Knight Amca #2736

  2. #12

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    Thanks Robbie,
    I had no idea, just my luck to have one year only handlebars and throttle. Now i know what info to seek. Thanks!!! It is a cool set of bar and risers and they help make the bike fit me very well so i'll stick with this setup. I'll report as i work thru this.
    bobwark

  3. #13
    Join Date
    Jan 2003
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    England
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    Yes those are good tips to check if the spirals are more than a few thousandths shorter than the bars. And you may be missing the 3320-10 roller on top of the plunger pin, which would give plenty of slop in the throttle spirals. I've also made some 3321-31A roller blocks if you have worn slots in the bars. These are 7/16" x 1/2" so you can file out the 3/8" slot to fit if it is worn. Finally I reckon the correct carb for a 1937 ULH would be an M51L with the 1 1/8" venturi.

  4. #14
    Join Date
    Sep 2007
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    Jersey City
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    2,075

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    Quote Originally Posted by Rubone View Post
    What "manual" are you looking at Bob? The -53 part number throttle used from '54 up is totally different. So is the '48 and earlier one. You need the '49 type throttle information to make sense of it.
    Rob, the picture of the bars above my post wasn't up when I posted. Bob

  5. #15
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    Rob, the picture of the bars above my post wasn't up when I posted. Bob
    Bob Luland,
    Two different Bobs on this thread, I was responding to the OP about his post.
    Bobwark,
    Those are not one year only, just that '49 was the first year that type was used and if your manual does not show that type it is tough to understand them. They have an internal spiral affair. But the total amount of travel is still compatible with Sidevalve throttle arms for full travel . So it is a matter of finding where you are losing the movement.
    As noted before, the spool on the end of the outer cable must be locked solidly in the bars by the set screw, and the outer cable must be flush with the throttle side of the spool.
    Also note that at full travel of the throttle arm on the carb when it hits the stop it is beyond full throttle and is actually slightly closing again. The throttle cable must be set on the idle side of travel, not the full open side. Not sure how you are approaching this.
    Robbie Knight Amca #2736

  6. #16

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    My Manual is the repop of the factory 1937-1948 and yes my throttle assembly is different, no roller or pin as can be seen in the image i posted. Just my luck to have an oddball. Yes, my carb is M51 with the 1 1/8 venturi tube. When i sent the carb to Kevin a Rust Never Sleeps he noted it had the wrong venturi tube and put the correct one in. I guess i'll just fool with what i have and see how good i can get it. Sounds like plan B would be a more common year/style handlebar and throttle assembly. My bike has a repop ('38-39 style, V-Twin) frame so it will never be show 'worthy' ( a 'box of parts' as someone described it,,i was sooo offended,,,not really!)so a few deviations aren't a horrible thing to me. The bike has a vast majority of the 'right' parts but is a rider/bobber will never be in a show. Rode it 2K miles last year and hope for more this.

  7. #17

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    "As noted before, the spool on the end of the outer cable must be locked solidly in the bars by the set screw" I've been looking and can not find the set screw you mention,,,a hint?
    Thanks everyone for their help.
    bob wark

  8. #18

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    Progress! After removing the switch housing i found the hidden grub screw which secures the spool that the outer cable is secured to,,,,,and hence the grub screw holds firm in the 'bar. My cable seems to be a very tight fit within the spool, in fact so far i can't seem to get it in there, maybe chilled cable and heated spool? Do these two parts normally fit together so tight that they need no mechanical affixing? Wondered if i might (carefully solder the spool to the outer. I believe before i just pulled this apart that the cable was loose in the end of bar and not withing the spool. Thanks again everyone, i do dearly love this bike and riding it is pure joy for me.

  9. #19

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    Joy! Success! My cable had escaped from the spool which holds in in place. Reassembled (properly,,,i think!) and lubed my throttle feels great and works great, full travel or darn near. A test ride can't be too far away,,,unless it snows as much as they say it might tonite!!!

  10. #20

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    Should the spool be soldered to the cable casing?

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