Topic: What is wrong with this picture

[tennesseebreeze]

I know it's not a sohc4, but I've been having trouble with my 400 Hawk. It tends to eat chains and sprockets. I have an o-ring chain and oem sprocket (the third on this bike), and after trying different types of grease, I settled on keeping it wet with Dupont teflon wax. I've checked the chain tension, etc. Yet, even after a modest ride I've got metal dust all over the chain. It's just chewing up the sprocket, and I have to keep adjusting the chain tension. Sometimes it's loose, sometimes seems too tight.

I may have discovered the reason. It seems from this picture that my wheel isn't plumb. What the hell? Wouldn't I feel it in the ride somehow? The only thing I can think is that the swingarm is bent, or that the bushings are worn. But there doesn't seem to be any play in them- much less the amount needed to make the wheel that out of plumb. Any theories?

[70CB750]

Take the wheel off, put the axle back in and check if the rear axle and the swingarm hinge are parallel, the picture sure shows something not right, bearing maybe?

[evanphi]

Yeah something is waaaaaay off there.

Was the bike ever crashed or hit by another vehicle? 70CB750's advice is good. Your swingarm could be twisted or a bearing could be bust.

[tennesseebreeze]

Yeah something is waaaaaay off there.

Was the bike ever crashed or hit by another vehicle? 70CB750's advice is good. Your swingarm could be twisted or a bearing could be bust.

I got the bike about a year ago. I've never wrecked it, but it does have a dent in the tank like it was laid down. Not hard by the looks of it and by the condition of the whole bike. I'll check those bearings and see if there's any play in there or the swingarm. While riding, it feels a little squirrley if I'm taking an aggressive curve. I chalked it up to the worn out rear shocks, but it may be one of these other things. 

[martin99]

Placing a straight-edge or laser along the top of the chain run should indicate whether or not the chain is running true and if there is any deflection from the front sprocket to the rear wheel. Don't know about the Hawk, but not all bikes' rear wheels are exactly in line with the frame centre, odd as it may sound. I think it's unusual to see metal dust due to a worn sprocket, unless its possibly an aluminium one. I'd be more inclined to check lateral movement of the chain over the sprocket in the first instance, in case it's chewing away at the casing as it goes around the front sprocket. Another possibility is that your chain could be too wide, they do vary between makes.

[tennesseebreeze]

Wheel bearing would be my first suspicion. Are the axle adjusters holding? Perhaps the axle itself is bent?

I don't know the model, but area he wheels spoked? If so, checked the rear for true?

It's the 78 hawk. Those are Comstar wheels- plates of alloy bolted together with alloy rims. And they are in good shape- not bent or any signs of a wreck. As far as the adjusters- I replaced the bolts and meticulously adjust them. They are true and not bent. I'm leaning toward bearings too. Although if you look at the bottom of the shock springs are it appears that one is lower than the other. Which would indicate a twisted swingarm. I won't know until I get in there and take the wheel off.

[goldarrow]

The way the bike sits in picture is angled off.  Move camera a bit to the right. Before you start taking anything off the bike

[tennesseebreeze]

Placing a straight-edge or laser along the top of the chain run should indicate whether or not the chain is running true and if there is any deflection from the front sprocket to the rear wheel. Don't know about the Hawk, but not all bikes' rear wheels are exactly in line with the frame centre, odd as it may sound. I think it's unusual to see metal dust due to a worn sprocket, unless its possibly an aluminium one. I'd be more inclined to check lateral movement of the chain over the sprocket in the first instance, in case it's chewing away at the casing as it goes around the front sprocket. Another possibility is that your chain could be too wide, they do vary between makes.

It is an o-ring chain, so it has a wider outside width than a regular one. But the wheel spins freely and I don't believe it's rubbing the case. If you mean the inside width is wider than the sprocket- I don't think it is, but I'll double check that. Sprocket isn't aluminum and it's a fairly new condition salvage from the same model bike- so it should be pretty tough. But the original sprocket wore out till the teeth were razor sharp- so it lost a lot of metal.

[tennesseebreeze]

The way the bike sits in picture is angled off.  Move camera a bit to the right. Before you start taking anything off the bike

Yeah, I know. I was in a hurry when I took it. I still think the wheel is clearly not plumb.

[strynboen]

just take a straight vooden plank..and hold it on the side of the rear hveel..and see if it are parelel to the front hveel..evt use a par schrevs to press it in to the hveel so it are teight

[garyw]

Are the wheel spacers handed, is that the reason the wheel is over to the left as yes it does look vertical.
I'm having trouble posting a reply so this may be a bit late. But the wheel would be floating about if the bearings where so worn. You could/would feel it if you pushed and pulled the wheel on the centre stand.
Good luck sorting it gw.
 

[tennesseebreeze]

This, plus my 500 build, AND I'm ass-deep in putting a heater core into '95 Audi. It never ends!

[Bodi]

The swingarm is tweaked. Very common in crashes, even minor ones. I remove them and check on a known flat surface with the pivot bolt/collar/whatever supported parallel to the surface, then I can see how far out of alignment the axle slots are. Since the swingarm forks are fairly easy to bend out of whack, they are not hard to bend back. With the pivot end clamped to something sturdy I angle a 2x4 between the axle ends of the forks and twist them back into alignment.
I suppose if you rode with very unequal shock spring strengths in could eventually distort the forks as well. The left spring looks much heavier than the right one, possibly an image artifact: it is definitely not as compressed, probably from the right side of the swingarm being lower than the left.
You should check that the springs are identical and undamaged. I doubt that a shock (damping) difference would do anything.

[tennesseebreeze]

The shocks are both the same and have the same damping adjustment. They are worn out and in need of replacing though. There are no permanent shock mounts on top- just a bolt and a threaded hole in the frame. I'm remembering now that when I got the bike I took off the shock and found it had been cross-threaded on top. Probably wouldn't cause this problem, but should be fixed nonetheless.

[Old Scrambler]

Agree that the swingarm may be bent.................also suggest removing the wheel and place it on a true-ing stand of some sort...............the inner bolts that hold the sprocket to the hub are weak on those models and can't take side-load extremes..........such as hitting a curb

[martin99]

Only had a quick look earlier as I was at work, but having looked at it again I'm going to agree with Bodi and Old Scrambler. The rear wheel is way off perpendicular and it looks like even if it were straightened up it may still be quite a bit off centre to the left. Add to that the information regarding the broken shock mount and I would suggest it's been broadsided, breaking the shock mount and bending and twisting the swingarm.

Gotta say, there's more than a small element of safety (or lack of) here. It may be acceptable to drill small holes in the frame, but one big enough for a 10 or 12mm bolt to pass through at such a point of stress is very dodgy IMO. You really don't want to be riding that until it's sorted. 

[MiGhost]

It may just be the camera angle, but if you look past the wheel to the gauges. It looks as if the frame might be twisted

[70CB750]

I am sure once he starts taking it apart, the reason will present itself.

I especially like the idea from Bodi - lay the swingarm on flat surface to check it.

[tennesseebreeze]

It may just be the camera angle, but if you look past the wheel to the gauges. It looks as if the frame might be twisted

Damn- I noticed that too.

[tennesseebreeze]

Truth is I was going to sell this bike this spring. But I'm not the type to pass on a problem to someone else. If I sell it, I'll be sure it's a safe bike first.

[seanbarney41]

All that picture is really telling you is that the centerstand may not hold the bike perfectly vertical.  The only thing that is gonna wear a chain/sprockets that fast is front and rear sprockets out of line.  They could be offset or they could be twisted.  Why?  My guess is either wrong wheel spacers or a bent swingarm.  What kind of mileage have you done in a year?

[rb550four]

I would guess the distance on the bottom of the shock mount and the top shock mount would be equal in measurement on both sides of the frame.
  The stock shocks are the same size right? There is no offset on the top mount? If that is the case a measurement from the swingarm bolt to the top shock mount should be equal on both sides of the frame...if it is and the distance from both shock mounts are coming up different, I would seem to me that the swingarm tweaked. This may be a way to do a quick check without taking everything apart before you confirm your suspicion . Then when you are satisfied that you have the culprit, remove the swingarm and see how it lays on a known flat surface as stated in previous posts.

[DWS]

Looks like one of the swingarms are bent

[scottly]

How about some pics of the worn sprockets?

[tennesseebreeze]

All that picture is really telling you is that the centerstand may not hold the bike perfectly vertical.  The only thing that is gonna wear a chain/sprockets that fast is front and rear sprockets out of line.  They could be offset or they could be twisted.  Why?  My guess is either wrong wheel spacers or a bent swingarm.  What kind of mileage have you done in a year?

I'd say I did just about 1500-2000 miles on it last year.