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post #4 of (permalink) Old 08-06-2011, 07:13 PM
k12techman
Grand Prix 125
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Join Date: Jun 2008
Location: Kansas
Posts: 40
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I've been fighting with the chirping noise on my 2010 Thunderbird for some time now. I have a bit over 12K miles on the bike and don't ever notice the chirping being a problem until I let the dealership touch the bike.

I've scoured the Internet to find anyone that's had the same problem and to read how they solved it. After spending the better part of all weekend for the past few weekends, I think I have it narrowed down to two things:

1. Belt tension
2. Wheel alignment

With the bike on the side stand, Triumph says that a 10lb force should deflect the belt between .20" and .27". MAN is that TIGHT. But, sure enough, if you don't put it under that tension, the belt chirps. I do wonder about the longevity of the front pulley and output shaft with the belt under that much tension. For what it's worth, setting the belt tension is actually the easy part of the whole process.

I put my bike up on a jack stand and get the bike perpendicular to the garage floor. Following the procedure outlined in the service manual, I loosen the axle nut but DON'T remove it. Then, I put the jack up a couple more pumps to make sure the bike's rear tire is off the floor. (If you ask me, there's no great place to use a jack on the Thunderbird. Sure do wish I had a whole bike lift). Now I loosen and remove the lock nuts from the adjustment slides at the very rear of the swing arm. I can now make the tension adjustment using the adjustment nuts that butt up against the very rear of the swing arm.

BUT, this ain't over just yet. Now you have to make sure that the wheel is aligned as well. There's been mention on several forums of a special tool that Triumph has to adjust the rear tire on the Thunderbird. Evidently it consists of a rod that goes through the axle and then matches up on the swing arm to somehow show the wheel is aligned. I have not been able to find this tool anywhere on the Internet and my dealer says Triumph won't sell it to individuals. As a matter of fact, they didn't want to show me the one they had very badly.

So, the next stop might be to simply measure how much thread is showing on both adjuster bolts and make sure they are even, right? Nope, not on my bike. Those adjuster bolts aren't the same length! As a matter of fact, there's a 3mm difference between them. So, you can't just measure thread left and think your wheel is aligned.

I got crazy with mine. I decided to measure from the center of the swing arm bolt to the center of the axle hole at the back. On the left side of the bike, this isn't too hard. On the right side, I had to remove the pulley cover and the coolant reservoir to see the bolt.

Once I could see both sides of the swing arm bolt, I measure on both sides and got it within about 0.3mm. Should be close enough. Once I confirmed that the wheel was aligned this way, I snugged things up and took it for a test run. No chirp, no noise.

So, I brought it back to the garage to get ready to put the other parts back on. Before I did that, though, I measured from the center of the axle hole to the rear of the swing arm to see if that measurement was the same on both sides. This way I don't ever have to take the damn pulley cover and reservoir loose again just to check wheel alignment. Sure enough (and as you'd expect), those measurements were equal.

So, I think I have the belt tension adjusted correctly and the wheel aligned. I even sprung for one of those little belt tension tools that lets you put exactly 10lbs. of force to the belt and measure it's deflection. Mine comes to just a hair over .25" of deflection. But, like I said before, that belt sure seems damn tight, IMO.

A couple of notes here:

Do NOT use the little "guides" on the sides of the frame to try and align the rear wheel. Those little guides and the groove in the adjuster are about as useful as **** on a bull.

Do NOT count on the bolts from the adjusters to be the same length. I did at first and couldn't get the wheel aligned. So, I finally decided to measure the bolts themselves from where the adjuster touches the axle to the end of the bolt. There were NOT the same length.

Do measure from the center of the swing arm bolt to the center of the axle bolt to get a good idea of whether or not the wheel is aligned. I figured the swing arm bolt and the axle have to be perfectly parallel, so they should be equally distant on both sides of the bike from the axle.

Do NOT trust that the dealership knows how to align the rear wheel of a Thunderbird. They told me that some belts just chirp and that all I need to do was buy louder pipes so I didn't hear it. I'm not against the louder pipes, but I don't want to just cover up a problem; I want it fixed.

Anybody see any flaws in my logic or what I did?

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