Belt alignment and damage to alternate teeth

Gez

Gez

Club Member
For the purpose of keeping stamps in the service book, I got my FXLR Low Rider serviced by a local independant motorcycle workshop. They have a good reputation and look after some customers Harleys. I also asked them to put a new rear tyre on. That was not long before I garaged the bike for the winter, but I did suspect something was not right with the drive belt alignment.
Took the bike for a ride, two up today, and out of interest, took a closer look at the belt. See photo 11. The belt is rubbing on outer edge. I know it should run close to the outer side of the pulley, but shouldn't rub, should it? Image 10 shows the rubbing marks. Image 5 shows the other side of the belt, untouched.
Other, more serious problem. Every alternate tooth on the inner edge of the belt shows heavy marks on the rear, inner side of alternate teeth, (upper run) One or two are showing slight fraying.
Gonna ring the garage tomorrow for them to take a look and start by proper realignment. What's the prognosis re the inner markings? Maybe a damaged pulley tooth/teeth?
Gonna see what they say but will probably end up sorting myself. I'm hoping belt remains serviceable. Btw, front pulley looks clean and fine.
Help/advice/reassurance etc would be appreciated. Thanks

image11.jpeg

image12.jpeg

image10.jpeg

image5.jpeg

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When the tyre was fitted did they cross the axle spacers over When the wheel went back ? That would take the wheel over enough to cause it ,as for teeth wear all belts end up with a wear face how many miles up ? I did a dyna years ago where the belt was not tensioned correctly at the Pdi ie loose and it looked just like that at around 3k it took ages to get hd uk to cough up for the belt and labour as he refused to go back to the main dealer where the bike came from 🤷‍♂️
 
I'll mention the spacers to them..... Can't the axle be realigned correctly using the bolts on each side just behind the axle, having first slightly eased the axle nut? The marks on the belt look like damage rather than wear. Asking these questions as Haynes don't do a manual to help me. Need to get myself a tension gauge and a socket for axle nut. Father's day presents.
Bike done only 9K miles
 
Try putting it back together then wind the wheel spindle adjusters back out a touch then back in until they touch the wheel spindle then measure from the swing arm pivot centre to the centre of the wheel spindle turn em in untill both sides are even , then a 1/4 turn or 3 flats at a time left then right measure turn L then R measure and keep doing this until the belt reaches the tension given in your owners handbook the measurement must be equal on both sides then spin the wheel to see if the belt “walks” to the side of the pulley see if this sorts it
 
Took the bike back to the workshop that fitted the tyre and service. Left it with them. Gonna align again properly and check what might have caused the damage to alternate teeth on inner edges.
Thanks for information. As the damage is on the inner edge looks like a belt replacement is on the cards at some point. (see bottom photo on my original post). Will have to monitor for now. See what the workshop says as well. Thanks Dazzlin, very helpful.
 
Tried 3 times (including reassembling exhausts etc, and short road tests, and its a pig to get in and out of the shed!) to get the drive belt to run slightly off the outer edge of the rear pulley.
I set it up, spin the rear wheel forwards, lots of turns, and it sits central on the pulley. Give it a run down the road and it ends up sitting on the outer edge again, although after the last attempt it's not as tight up against the edge as it used to be, so leaving it. Used a digital vernier caliper to measure between axle centre and the adjacent "flat" near the alignment bolts. Less than half a mm between each side. Think I'm doing everything right. Gonna run it and monitor it.
Is my experience par for the course?
 
I usually measure to the centre of the spindle, on the Fatboy there is a small centre mark on both ends. Also a centre mark on the swing arm spindle.
 
I have had a similar problem to this.
I bought a second hand Sportster that had no upper belt guard so I got hold of a second hand one which didn't quite fit so I modified it by moving on of the brackets.
I got the belt rubbing thing and delved into the whole alignment issue.
It turned out to be the belt rubbing on part of the old bracket I hadn't cut off.
Just saying this in case there's something else it could be rubbing on. Has anything been touched or altered lately?.
 
The rear spindle is hollow so no marks. Different internal diameter on each end. Offside 13mm, nearside 17mm, (or extremely close to) Using calipher between flat near adjusting bolt and nearest to flat inner surface of spindle, then adding the radius. 50mm one side and 50.4 on the other, after adjustment. Jacked bike up to spin rear wheel to clean belt. Spinning wheel forward the belt moves towards centre of pulley. Odd. Need to set it up (when jacked up) towards inner edge of pulley then when on ground and ridden, it should end up in correct place. Putting it down to tolerances etc. Also have a taller rear shock so more movement on wheel between on ground and "hanging" when jacked up. Thanks for feedback
M&M - had a rear tyre fitted last year but checked and double checked and sure nothing out of the ordinary. Why do Harleys need so much faffing?
 
My Sport Glide always ran with the belt over to one side of the pulley. No amount of adjusting stopped it, and I just learned to live with it. I did 11000 miles with it like that before it got written off.
 
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I was going to have another go using the method outlined above, but think I'll leave it for now and see how it goes after a long run. Just a bit worried that the edge of the belt will wear if too hard across. Think I worry too much!
 
Don't obsess about the belt running to the left of the rear pulley, even when perfectly adjusted the belt will track to the left flange of the rear pulley when the bike travels forward, turn the wheel backwards and the belt will track to the right flange after a few rotations.
The original belt drive models used to be fitted with a double flanged front (gearbox drive pulley) these were superseded and all replacement parts are now single, left hand side only flanged pullies.
Carefully inspect the pullies and flanges for damage, it's not unknown for stones or other objects to put nicks or indentations in the flanges and if so these can cause damage to the belt, if so on a rear flange it is possible to file this down to get a smooth(er) surface, it is also not unknown for ham-fisted removal of the rear wheel by not slackening the belt sufficiently or removing the guards to damage the pullies or mark the belt.

Check the, pullies, (the front will require grubbing around on the floor with a torch and getting the front pully to turn, easier if you have a bike lift.)

Check the belt alignment adjusters are the same both sides but also check the wheel/rear pully for runout and for loose bolts and also check the alignment of the wheels front and back, this is best done with two square section tubes but there are various methods to do this as again it is not uncommon to find this is out. ( This should not make a difference to the belt alignment unless some one has mis-aligned the belt adjusters to achieve wheel alignment!)
 
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AS STATED IN PREVIOUS POST Don't obsess about the belt running to the left of the rear pulley, even when perfectly adjusted the belt will track to the left flange of the rear pulley when the bike travels forward, turn the wheel backwards and the belt will track to the right flange after a few rotations.
Set my belt alignment using a laser tool and it still did exactly the above and having read this post I am going to stop worrying about it.
 
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At the very least you haven't fallen into the trap of trying to measure freehand to the centre of a hole!

There is and maybe it is worth making some kind of plug that will allow you to measure accurately to the centre of the hollow axle. My bike is the same.

Some swing arms have holes drilled close to the axle for alignment. On other bikes you measure from the swing arm pivot bolt.

There is a difference in my mind about obsessing to doing a job properly. It appears the belt running to one side or the other of the belt pulley is the norm but it clearly shouldn't do it to such an extent that the belt rubs and gets damaged.
 
I used a plasterboard fixing , and wrapped insulation tape around it to get the desired thickness , I then used a large Alan key with white insulation tape and sharpie to get the alignment right .

89D0D4F5-AB62-4ECA-A47E-E20EB6AE1218.jpeg
 
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You could also use a 12mm bolt and wrap insulation tape around it to get the size , according to Doc Harley , you can buy a gadget instead .
 
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