Secondary Belt Drive slipping

Energy One
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kevin05bdmcpr

Member
Just got a '05 BDM Chopper. Traded my '07 Streetglide I had since new. I still love choppers. I'm a semi-retired engineer and former HD mechanic. When I get down on it a bit I felt rear pulley/belt jumping/slipping.
I've built/owned a hardtail with one of the first S&S 113's ever made. Back in '96 if I remember right. I ran a 530 chain sec. and a 3" open pri. Now I think I may wish I had a 530 chain drive again. The belt was a bit loose 5/8" to 3/4" play on top. Adjusted to 1/4" to 3/16" play on top side. I've really never adj one this tight. Dont need to damage bearings. Took for a quick test run. I jumped on it hard and felt much better but I still felt it jump a little. I had marked it and it jumped 3 teeth. Much better but still not good. Darn, looked forward to a clean rim but if I need to convert to chain so be it. At 59 I still ride hard and why have a Sidewinder to just go putt putt. That ain't me. Any suggestions guys?
 
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Sven

Well-Known Member
Some obvious things like:

1. Is my axle tight and can I see the axle walk in the frame?
2. Where is my tooth height at the belt side?
3. Where is the tooth height and gaps of both sprockets?
4. Am I thinking a too loose belt for fear of bearing fatigue?
5. Is my transmission walking in the slots like the axle?
6. I should take a ride to the harley dealer and feel a belt on a new bike that is on the showroom floor.
7. I should look right now at my UUUU vs. Do I see an air gap where the belt's U is walking up a sprocket tooth I step on the bottom rung of the belt and step on top of the belt and see if it walks up a tooth?
 
KaptinAmerika

KaptinAmerika

Guru
You Definitely have something worn or out of alignment.
I have a 140hp 124, I weigh 300 pounds and my belt does not slip when I get on it hard.
 
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kevin05bdmcpr

Member
I looked at her again shortly after posting about the slipping. I was in a hurry earlier and I might be able to adjust it just a tad more. I am a little suspicious of the wear on the pulley. I do know that is not a common issue. The belt looks fine there are no cracks and it doesn't appear worn. Tomorrow I can spend a few minutes on it. Generally if a belt is properly maintained, belt/pulleys can get 75k+ miles. I've just gotten this bike and it appears to have been very well taken care of but then again you never know. I will compare measurements with an American Ironhorse Texas Chopper I'm currently working on. It doesn't have issues with slipping but the owner would certainly trade problems. I worked for American Ironhorse for a short while in their early days in Fort Worth. All my wrenching experience was in the Houston then Dallas-Fort Worth area years ago. Anyway I'll figure it out. Thanks for your advice what are specs on an 05 per BDM and Baker if anyone knows? I take deflection measurement just behind tranny pulley top side. Anyone with suggestions on sprocket teeth #s? I know that would probably be last resort although at my age I am old school and a good O ring chain would do the trick. Thanks
 
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kevin05bdmcpr

Member
The first full day I had this bike I rode it and quickly felt it surging and jerking at lower speeds. Just as I thought the primary chain was very loose. Very. That did make me wonder about how maintenance had or had not been done. It looks great never riden in the rain but that ain't everything that is for sure.
 
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pauly

Active Member
kevin05bdmcpr said:
I looked at her again shortly after posting about the slipping. I was in a hurry earlier and I might be able to adjust it just a tad more. I am a little suspicious of the wear on the pulley. I do know that is not a common issue. The belt looks fine there are no cracks and it doesn't appear worn. Tomorrow I can spend a few minutes on it. Generally if a belt is properly maintained, belt/pulleys can get 75k+ miles. I've just gotten this bike and it appears to have been very well taken care of but then again you never know. I will compare measurements with an American Ironhorse Texas Chopper I'm currently working on. It doesn't have issues with slipping but the owner would certainly trade problems. I worked for American Ironhorse for a short while in their early days in Fort Worth. All my wrenching experience was in the Houston then Dallas-Fort Worth area years ago. Anyway I'll figure it out. Thanks for your advice what are specs on an 05 per BDM and Baker if anyone knows? I take deflection measurement just behind tranny pulley top side. Anyone with suggestions on sprocket teeth #s? I know that would probably be last resort although at my age I am old school and a good O ring chain would do the trick. Thanks
Click to expand...

There isn't much in the workshop manual about the subject.

Paul.



 
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kevin05bdmcpr

Member
Thanks for the info. I had use of similar tools at shops I worked at before and 2 things I can fabricate to assist rear wheel alignment. I did it yesterday as shown for a hardtail.
My pulley is fine and I just need to tighten a bit more and get belt to 3/16" deflection. That seams tight but it is a 117 cu in. I love Baker and if they say the thing can handle that load on bearings than that is good enough for me.
My friends AIH doesn't have a problem and I have it at 1/2" but it's a wider belt too.
A wider belt/rear pulley would be great and a thought. The tranny pulley is wide enough.
Thanks guys
 
bearman

bearman

Active Member
kevin05bdmcpr said:
I just thought of something. I have a couple of different lasers and I could possibly use.
Click to expand...
Easiest way to align pulleys is to jack up rear wheel and spin tire.

roll tire forward, belt should ride a little to the right of center on the front pulley.

roll tire backward, belt should ride a little to the left of center on the front pulley.

adjust alignment till center of both movements is in center of front pulley and done, no special tools required.
 
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glennpg

New Member
Belt jumping

I have the same problem with an 05 Mastiff. Tried adjusting the tension on the belt but didn't eliminate the problem. Thought it was a little too tight so back of just a bit to 1/4" deflection. No visual where on the belt or pulley. Thought maybe changing the belt might help but hadnt done it yet.
 
harley74

harley74

Active Member
Mine does the same thing. I had supermax rebuild rear pulley and its still doing it. My bike is an 03 chopper.
 
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