Vertical angle alignment of pulleys

[orangedog]

I think I have found the reason for my belt chirp and unusual wear of the teflon coating on my pulley. As stated in the service manual I measured the vertical angle of the rear pulley, the transmission trap door and the motor using a Craftsman digital level. With the bike on the lift the tranmission and the motor read 89.6 degrees while the rear pulley shows 89.1, also confirmed rear pulley reading by verifying brake rotor read 89.1 as well. The manual states all readings should be within 0.1 degree of each other. Since this is an 05 with the Rolling Thunder frame I am not sure if the swingarm is not square or the motor/tranmission alignment is off. I am thinking that shimming of the transmission might be the best fix, but I wasn't sure if the motor would need to shimmed as well. I wanted to see if anyone had worked with this type of alignment issue before and what the resolution was. Any info would be appreciated.

Thanks, Rob

 

[Moespeeds]

loosen the tranny mounting bolts and engine mount bolts, and remove the entire primary. With a feeler gauge, check all the engine mounting points to make sure your motor is laying flat. Now torque down the motor plate to the motor, then to the tranny. With a feeler guage, check your engine mounts and tranny mounts to see if there is any space in there. From what I've heard, you very rarely need to shim the motor, so if you have some space under a motor mount, make sure nothing is hanging up underneath like an oil line or some dirt on the frame. Once everything is shimmed, torque down the motor and then the trans. Now align the rear end, and check to make sure your belt tracks smoothly in both directions. It may walk a little one direction or another, but make sure it's not climbing the sides of the pulley at all. Once mine started squealing, no amount of aligning or playing would stop the squeal, I had to get a new belt. Also, I'm pretty sure my transmission was not properly shimmed from the factory. When I tore my bike down, there were no shims under there, but when I put it back together, it needed a shim.

 

[lee]

yes but if his trans and motor are perfectly alinged (both 89.6) then it seems that just the rear wheel is out of tinker

 

[orangedog]

So the shimming of the transmission is just to get it aligned with the motor and prevent any stress caused by a gap under the transmission before you torque it down? Until your explanation I had been thinking that it was to align the motor/transmission with the rear wheel. Now the problem is starting to sound more like a swingarm problem. This may make sense since I think Big Dog has had some problems with swingarms on the 05 models because my service manual states when aligning the rear wheel to verify swingarm trueness if it is a Rolling Thunder frame. The only fix I can see for this would be a new swingarm since it doesn't allow for any vertical adjustment of the axle.

Thanks, Rob

 

[lee]

if you do nail it down to the swing arm it might be better to just replace the bearings and bushings etc to see if that puts it right. First off I would try to check if your rear wheel is sitting square in the swingarm. You need to know exactly what the problem is before throwing money at it.

 

[TCALZ06]

you need to follow the alignment procedure in the manual.
If you don't have access to it I could fax it to you if you PM me your fax number.

I'll bet your trans needs shimmed.

 

[Moespeeds]

I think by taking a digital level to it, you just complicated the problem. I bet if we all took digital levels to our swingarms, nobody would be perfect. Double check your tranny shim, then align your rear wheel. Here is how I aligned mine, toss what's in the manual, of the 4 Big Dogs I've worked on, not one was properly aligned from the factory or the dealer. Get a caliper and a punch. Find the exact center of your axle on both sides, and punch a mark into it. Measure from the center of your pivot axle to this mark on both sides. Get the proper belt tension and even them up. Now double check your measurement from the front of the cutouts for axle adjustment in the swingarm. You can really use any 2 common points on the frame, but this is what I use. If your tranny is properly shimmed, and the rear properly aligned, when you spin the rear on the lift, your belt shouldn't walk much at all, even when you spin it backwards. In my experience, once a belt starts squealing, no amount of alignment will fix it. You must change the belt.

 

[orangedog]

I have been working on the bike as much as my schedule allows since starting this post. Luckily I have a backup bike keep from going completely crazy. I e-mailed BDM about the problem since I had brought up the pulley wear and belt chirp to 2 different dealers in my area before my warranty expired, but it quickly turned into a pissing match. Since the dealers found no problem, they were unwilling to provide any support or advice. I finally found a guy at BDM who was willing to help me and we have been trading e-mails almost every day.

I have definitely convinced him that there is a problem by providing details about my belt tracking specifically on the front pulley. With the rear wheel aligned horizontally the belt tracks all the way to the inside of the front pulley, in fact I just barely got a 0.010" feeler gauge between the belt and the tranmission trap door. On the rear pulley the belt also tracks to the inside and rubs heavily on the inside retaining ring. As per his suggestion I tried misaligning the rear wheel in both directions, but could not get the belt to move from the inside of the front pulley.

I divised a way to alter the vertical alignment to test its affect on belt tracking. I pulled the axle to the right side until it was not engaged with the swingarm on the left. I used a longer but smaller diameter bolt to support the left side of the axle and then used an assortment of feeler gauges positioned under that bolt so I could get the rear pulley to match the vertical angle of the front pulley. I setup the horizontal alignment and properly tensioned the belt. I started spinning the wheel and within 5 revolutions the belt was tracking just slightly to the left of dead center on the front pulley!!!!!! The belt tracked just to the outside of the rear pulley but I couldn't hear any rubbing.

This convinced both of us that the vertical alignment being off 0.4 degrees was definitely a problem. He suggested checking the side plates of the swingarm to see if it indicated that the swingarm had bent and also to pull the right side swingarm pivot bolt, both checked out fine. We are discussing the next thing to try.

I have suggested a fix that he is not in favor of but I wanted to run it by you all. I only need to raise the left side of the axle by about 0.080" so I am considering grinding a flat on the axle where it goes through the swingarm and then use a shim under the axle to force the flat spot against the top of the slot in the swingarm. The thickness of the axle in that spot is over 0.250" thick from the bolt holt to the outside of the axle so I don't think it would significantly weaken it.

As far as adjusting the angle by using shims, since the transmission and motor are aligned I would have to shim both when adjusting the angle, which seems like opening a can of worms.

Sorry for the long post..............Rob

 

[117bigdog]

can you post some pics of all the measurements you are doing. with the vertical and horizontal angles.

 

[lee]

I guess my immediate response Orange might be that two wrongs don't make a right - especially on a bike

 

[orangedog]

For the horizontal angle I am just using the method that Moe mentioned above measuring from an allen wrench installed in the swingarm pivot bolt to the center of the axle bolt on each side.

For the vertical angle measurement I purchased a digital level from Sears which works very well. I initally measured the angle of the tranmission by placing the level against the trap door, but just to confirm the readings I have removed the the transmission pulley guard to measure the front pulley.

Also here is a picture of how I temporarily raised the left side of the swingarm to get the vertical angle of the rear pulley to match the front pulley.

I am convinced that the problem is with the swingarm since the tire actually becomes centered in the rear fender when the left side of the axle is raised to get the vertical angles to match.

Rob

 

[TCALZ06]

HI Rob,

I don't think you can go by the rear fender. I found a rear turn signal loose this weekend and I noticed one side was easier to get to than the other because of more space for the wrench but my bike seems to be aligned well without any wear problems at 13k

 

[DRBarnhart]

Rob,

I think you're right about the swingarm being the problem. Would I be correct in assuming that you've checked the pivot bushings/bearings for wear? If the swingarm is bent then it seems the only fix would be to replace it or get it straightened. (Duh!)

You're idea of grinding/shimming the axle isn't a bad temporary idea but unless you can properly check the axle for stresses by using something like MagnaFlux or eddy current... sure would hate for the axle to break.

If you do decide to shim the tranny to match the rear pulley I would also do the same for the engine so there's no .5 degree twist in the primary. Personally, I wouldn't put two major assemblies out of alignment to compensate for another that is, but that's just me.

There's a couple more threads on here somewhere about rear tires that are wearing off center and I'll be they have the same problem that you do!

Good troubleshootin' dude!!! :up:

Dennis

 

[alhall88]

The next thing I would do to verify would be to pull the rear wheel and put the axle back into the swingarm and check level across the axle (assuming the axle is straight). Those pockets are machined and should be straight with each other. If there is an issue with the swingarm it would show up here as well.

 

[kickstart]

Have you verified the Sears level is accurate?

 

[stlmikie]

Alhall and kickstar have valid points. If you are using the level and haven't verified the trueness of it make sure to always use the same side toward the piece that you are reading and the same side up or down each time. Not trying to be a wise guy at all just know a little about levels.

 

[DRBarnhart]

It appears in the photos that he's using the same side of the level for all measurements.

The only value that's important is the .5 degree difference in his forward and rear measurements when the manual states it should be no more than .1 degrees. As long as he didn't "re-zero" the level between taking these measurements his results are good.

Dennis

 

[PurpleDog]

The next thing I would do to verify would be to pull the rear wheel and put the axle back into the swingarm and check level across the axle (assuming the axle is straight). Those pockets are machined and should be straight with each other. If there is an issue with the swingarm it would show up here as well.

:up: definitely agree here. i use one of those digital pro levels (similar) on my car chassis and them suckers tend to be accurate for that sort of stuff. as others said, measuring differences here is key otherwise i'm sure he'd also be base lining his jig/lift in this case too. I too wouldn't cut axle personally, but rather sort out the root of prob esp since you've gone to the trouble thus far. Once confirmed via Alhall suggestion above, maybe drop swing arm and further isolate source. Use that level (on known baseline) on various points of swing arm to verify straightness, if that checks out, maybe swap bushing/bearing and try again in frame? Good work.

 

[orangedog]

Thanks for all the help, I really do appreciate it.

As you all have stated I don't know how accurate the level is, but as many measurements as I have taken, I can say that it is very repeatable.

To make sure there were no issues with the pulley or wheel bearings I did measure the angle of the axle by placing the level on the top of the axle between the sides of the swingarm. I compared this to a measurement of the front pulley where I placed the level on top of the front pulley parallel to the teeth and I see the same 0.5 degree difference.

As suggested by Doug at BDM I used a caliper to measure the gap between the side plates of the swingarm and the side plates of the frame comparing the readings at the top and bottom. I only got a few thousandths difference and since the top of the tire/wheel moves by about 1/8" when I temporarily got the angles to match I wouldn't think the swingarm bearings are the issue.

I am going to see how much a new swingarm is from BDM.

Rob