Hello, I'd like to know if on anyone else's 250 sf, is the rear wheel closer to the right swing arm vs the left? Also, does your drive chain make a zingy buzzy sound when sliding across the black guides? Your help is greatly appreciated!

 

No and no

 

So I did some testing and measuring. Turns out my rear tire is approx a half an inch or so to the right. Had my tires replaced last Nov and guessing the tech put the spacers in wrong or something. This may also be the cause of my drive chain clattering. Or it just may be it sliding over the guides/rests. Taking the bike back in for the correction on Tues.

 

All you need to do is measure - measure from the center of the swing arm pivot to the center of the axle on both sides and adjust until they are equal. Then sight up the chain line from behind, it should be straight, no visual offset. You can also look at the tire at the front to see if it lines up centered to the swing arm. The clearance at the sides may or may not be equal due to the chain requiring the swing arm usually being a shade wider to that side.

Now if your wheel is offset it is either supposed to be that way or the wheel has gotten offset when tightening spokes one time or another. I would find it hard to believe they can swap spacers since they usually only fit one way on most bikes, but I'm not positive on the 250.

I don't know about the buzzing on the swingarm guide, they will make some noise when sliding over it, since they do drape over it and touch. By all means do NOT overtighten your drive chain, you're better off with it too loose than too tight.

The way to know exactly how much slack your chain should have you can do the following:

• the swingarm arc will have the chain loosest at full extension and full compression, the tightest point is when the swing arm pivot, counter shaft sprocket, and rear axle centers line up in the same plane.
• compress the rear suspension until the swing arm pivot, counter shaft sprocket and rear axle centers line up, the tightest point for the chain.
• adjust the chain for about 1/2-1" play.
• release the suspension.
• measure the play in the chain now - That is what you need to have to avoid possible chain breakage or countershaft bearing/ wheel bearing damage.

Now when you adjust your rear chain you adjust it to that amount of play, no matter how loose it may seem to be. As long as the chain line is true the chain will not derail.

Now once you figure out if your rear wheel is aligned to center, you should be able to deal with the rest.

 

From the sidewall of the rear tire to the swingarm on the right, there's a finger size of space. On the left side, there's about two fingers worth of space.

I've sighted the chain and there isn't any visual offset. Though it still chatters. I lube it pretty often (Dupont Teflon Chain Saver), but maybe it just needs it more often? My bike stays outside, though I use a cover when it rains. I also recently cleaned the chain with diesel fuel (as stated in the manual). The slack is as it should be. Definitely not too tight.

The notches on the ends of the swingarm are set to the same on each side. After measuring from the pivots to the axle, the measurements are also the same. ~21.5"

There's no abnormal wear on the tire, from what I can see. The bike doesn't pull to one side or the other.

FWIW, I did a measurement with a 2x4 where I straightened the front wheel, held the 2x4 up next to, flush with, the rear tire to create a long perpendicular line with the front. There was ~ inch of space between the 2x4 and the front tire when I did this on the right side. When I did it on the left, the 2x4 was against BOTH front and rear tire when held in line with the rear. So again, the rear is about 1/2" more to the right. It's just quite visible when looking at the tire sidewalls next to each swingarm side.

The rear is straight in line, just not in the center of the swingarm. Perhaps I'm just being ****? It is a dirt-bike, after all... It doesn't go past 85/90 mph. And the fastest I cruise is around 65/70. Perhaps I'm just being **** retentive? It's just a bit...off-putting to discover such a thing on your beloved motorbike, ya know?

 

didn't read all above, but there are two different spacers for the rear wheel . one is marked "R" at least that's the case on the 2007 model.

 

picture please

 

Right Side:


Left Side, you can make out the swingarm under the chain:
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Another view, right side:
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Another view, left side:
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You can clearly see, the tire is closer to the right swingarm than the left. Any word on whether or not this is normal would be great.

 

My thought is this might be the problem. It only takes a very slight amount of difference from the axle being out of center to show up at the tire.

IF possible try setting the bike on a stand so the rear tire is off the ground. Start it put it in 2nd or 3rd and see if the chain is catching on the sprocket. If you do this just be careful.

 

since the swing arm pivot to axle is equal side to side (I never trust the marks) you KNOW your wheel is properly centered in the swing arm. this is pretty well proven too by the straight chain line from rear to front sprocket. As for your chain ******, look closely at your sprockets, especially your front sprocket to verify there is no hooking. The stress on the chain when running will wear the sprocket on the side that is loaded and pulling. The U shape will become imperfect showing that wear. Since the front is smallest it gets the most wear, teeth contact chain more often. Usually any noise is loudest when rolling backward, the hooking will catch the chain if bad enough.

Your rear wheel is trued slightly off center, could be because it is the SM version and they just made sure there was clearance on the chain, which can have a bit of side to side play while running. It could be factory or not. If you are not the original owner it could be possible the wheel has been offset more to fit one size wider tire on the bike. As said, the chain will move side to side a bit, but the swing arm doesn't, so that extra space could be allowing one size wider tire on the bike without clearance problems, but that's just a guess.
You could look at some other SM versions and see if the shop manual has anything about the wheel being laced with an offset then see if yours has the proper offset.

Bikes are not perfectly balanced by any stretch, so that slight bit of being out of track won't really have major effects on the handling.

You could re-true the rear rim, moving it over half the offset you measured. It is easy to do if you know how to true wheels, simply loosen the right side a turn on all the spokes then tighten the left side about a turn (how much actually depends on spoke angles). This is where you need to know how to true wheels. Once the major change is done the wheel should be trued both radially and side to side within a reasonable amount - again knowing how to true wheels.

I hope this helps a bit. I personally would not get overly concerned, but would probably re-true the wheel moving the offset sometime in the future. The biggest concern is that your chain line was straight and true. That is what could screw up the works if it was out of line enough to cause derailment.