This is an issue I have never encountered before. I'm not even sure if I know just how to describe it, but here goes: Quick Background: 2008 Softail Deluxe, stock other than pipe (Rinehart 2-into-1), air intake, and Tuner (fuelpak). Not my bike, working on it for a friend. We took a 2000 mile trip 2 weeks ago and upon returning this bike broke a weld on the rear swing arm belt guard bracket, belt guard vibrated down in between the swing arm and rear tire. Chewed up the tire and somewhat damaged the belt. Discovered as he pulled into his driveway....luckily!!! I had another wheel/tire to install, but belt needed to be replaced, and bracket needed to be re-welded on to swing arm. So, bike was torn down, bracket repair completed, new 'carbon fiber' belt installed (133T/1"), and bike reassembled. All 'seemed' well until taken on test drive. I did this work alone in my garage. I've been doing this for 30+ years, am a past ASE Certified Master Auto Mechanic, and pretty competent at this level of repair. But, I'll be the first to admit I can make a mistake.

So, I back the bike out of my garage, on to the street, and take off on a 1 mile test drive. Light acceleration, 1/2 upshift, stop sign, fine. Go around the first turn, accelerate gently around a curve, get into 3rd, another stop sign, fine! Make the next turn, pull out on to main road, a good straight section, I twist the throttle a bit harder in 1st, and it starts making symptom I've never experienced previously in my near 60 years of riding. There is a very distinct 'slippage' that has a bit of a vibration associated with it, but no 'mechanical' noise (as in no grinding or metal-to-metal sound). I back of immediately, make the 1/2 upshift, and gently return home. I get it into my garage and the belt appears really loose. So, I tighten it, go for another test drive, and same thing. Go home, and belt is loose again. My gut is now telling me that this 'problem' is a function of this 'newer' type belt.....this 'carbon fiber reinforced 20% stronger' belt that my friend purchased for this bike and paid around $100 for. The first thing I noted with he handed it to me was that it was EXTREMELY flexible. Having never used anything other than genuine HD belts in the past, this belt was clearly 'different'. I pointed this out to me friend, but he told me it was supposed to be a 'better' belt. I did some research on these carbon-fiber belts, and that seemed to support his statement. So, I went ahead with the installation, and now I'm getting this 'problem'.

So my questions here are this: 1) Do these carbon fiber belts have some kind of initial 'break-in' period where they do stretch initially and then quit and hold adjustment? Next, 2) Could the symptom I feel be something OTHER than a slipping belt, like maybe the compensator? 3) If it IS the compensator, which I've replaced in the past as a result of start-up issues and the ratcheting noise associated with that problem....if the compensator is slipping under hard 1st gear acceleration, wouldn't I hear some more dramatic noise from it? Again, this slipping problem is more a 'feel' thing. You can sense a vibration in the seat, but you also hear the engine RPMs jumping. So, clearly there's something going on.......and I'm just not sure what.

As another consideration did occur to me, I thought that possibly this could be a function of some slippage in the compensator. BUT, the engine starts fine, no 'grinding' or other odd noises. Just a smooth start-up like any 'normal' Harley. My experience with bad compensators is that they make a hell of a racket when attempting to start the engine. Some will slip so badly they won't even turn the crank over. They also have a pretty characteristic noise, AND, once the engine is started I've yet to see one that jumps when riding. So, I'm kinda ruling that out....which takes me back to the belt. I dare say the adjuster bolts in the rear aren't turning outward enough in one ride around the block to cause this belt to loosen up so much so as to start jumping teeth, so I'm back to 'stretching'.

I'm going to go ride it again, and maybe try one more time to tighten the belt. But, if it jumps on the 4th try, I'm stopping altogether and seeking further advice. Anyone with any thoughts or comments here, please let me know.......and many thanks!!

Tom D.

 

Toothed drive belts don't stretch.. Did the guy bought it off of Ebay? It may be counterfeit.

 

Check to see if the front pulley is loose. If so, the pulley splines could well have stripped.

 

Clutch adjusted properly?

 

Never seen a belt of any kind do what your talking about.
Clutch was my first thought.

Front drive pulley ?

I can't see a compensator doing this.

WP

 

Yea, an ebay purchase. I don't know what you mean by 'counterfeit'? There are a LOT of belts available on ebay that say they're direct replacements for an OE belt. Some even come with the OEM part number, which in this case is 40058-07. Even Drag Specialties has their version of this. But, 'counterfeit'? I don't know that actually applies. 'Aftermarket', yes!! Non-original, or non-HD.....absolutely! But I think to be 'counterfeit' it would have to have been represented as an OEM part, but then actually 'not' be an OEM part!

This was sold at a 'carbon-fiber' reinforced 'replacement' drive belt for this bike and this part number. It did arrive with a sticker on it that had the HD part number written in ink pen and stuck on the top-side of the belt. And, in researching drive belts in general, I did find that these carbon fiber belts are considered to be 'as strong' or even stronger (some advertise being 20% stronger than an OE belt). They also say they are lighter and more flexible, and can actually improve MPG (which may be a stretch....no pun intended!). But to me, the lighter and more flexible may just mean more chance to have the pliability result in slippage, or as HD puts it: Ratcheting. Belt came with no documentation, just a folded up belt with a sticker on it and stuck in a reinforced plastic mailer-envelope. So, I honestly don't know if the tensioning for this belt is the same as that of an OE HD belt or not. In using OE HD belts in the past, I've NEVER had one 'ratchet' on me.....even once. And, I've built some pretty potent engines. But, as I said, I've never used anything other than an OE HD belt. So, I'm giving it another couple of days, a few more test runs, and some further documented adjustments, including purchasing a 'new' belt tension adjustment tool arriving tomorrow.... just in case my old one is 'off' (cuz it's old like me!!). But if I get a continued ratcheting after two or three more test runs, complete with re-tensioning as per factory book-spec, I'm replacing it with a genuine HD part. I just had a 'gut' feeling about this belt when I first saw it.....and now it looks like this belt's performance is confirming my suspicions.

 

It may be a replacement belt labeled as something like Gates, or BDL but is really some chinese knockoff.. I've seen things like champion / NGK plugs that when you look at them closely, they are really counterfeit. I bought a RK 530 drive chain off ebay that appear counterfeit..

 

I have over 1000 purchases on ebay. The only stuff I buy from ebay is either one of a kind used vintage replacement (some used) stuff like vintage Lionel train stuff (example) or from companies that already have an established business OTHER THAN EBAY. Even the used vintage stuff can be a knock off.

For car or motorcycle parts, I only buy from a company that has established name, website with online ordering, and an established history like a Dennis Kirk or Lowbrow customs, etc (there are more and just using those names as an example). Those that have an independent site, established history and bonified website, but also sell on ebay for more exposure.

Knock offs are a big problem. Suspect anything. Even ball bearings! It's a damn shame but it is a problem.

If the belt is slipping you will eventually see signs of slippage. Might need a magnifying glass to look at the belt for signs of slippage, but eventually you will find an indicator. My initial thought on your description was slipping clutch. However, if your buddy bought from a small ebay only company with little or no history, suspect the belt.

 

Sounds like ya have a plan.
Please let us know how things turn out

WP

 

I've killed 3 belts. One was an inner primary when the crank nut spun off. A rear I snapped..

I really have problems with belts jumping teeth.. I would think that the belt would have to be very very loose for it to happen, or the teeth were missing on either the belt or pulley.

I've never had one jump teeth but had one rip a section off teeth loose due to belt alignment issues. My Fault on a custom bike I built. Happened on a dyno. Drive the bike home and found about the belt had split a section of teeth away from the main cord backing. They stayed in place but made a weird sound / vibration under load..