Rear wheel off-center, is this supposed to be this way??

Danny500 · May 20, 2009, 08:43:46 AM

Looking at my bike, dead on from the rear end (while on center stand) the center of the rear wheel is out of align with the rest of the motorcycle.

Considering my frame is straight, my plastics, fender, and tail light are all mounted square on it... the center tread of the wheel is slightly to the left of center. Even going under the fender the left side of the wheel is closer to the inside wall of the fender than the right side.

Is this normal? It's been like this for a while, and I do notice odd handling characteristics (yes, even when the shocks are working properly and the forks are not leaking like crazy.)

I also think it's off because if I go to wheelie (i know, I know.. not normal operation, but it enlightened me to something) that the bike tends to want to roll or tilt over to the right side, thus thinking the bike isn't balanced on the rear wheel properly.

Not that that's a huge issue... the issue lies mainly in cornering... it takes lefts like nobodys business, but right turns are really hard to hold the line and there's a distinct wiggle in the rear.

I almost wonder if my swingarm is somehow bent...

The rear wheel is mounted properly. I just don't know. Unless this is how the GS is built? Which wouldn't surprise me.

The Buddha · May 20, 2009, 08:51:41 AM

Someone forgot to puy in a spacer and bolted the swingarm tight to grip it. I am betting the left side - cush to swingarm spacer has been left out.
Cool.
Buddha.

joshr08 · May 20, 2009, 09:01:57 AM

yeah most of the time that spacer stays with the cush drive but is known to fall off and get lost from time to time. i would bet your missing that spacer as well

Danny500 · May 20, 2009, 09:24:10 PM

Definitely not... I hope. Due to the fact that there's only 1 spacer there, and it's always, always been there as long as I've had the bike. I've had the rear wheel off twice and made sure everything went back on.. plus, if that spacer wasn't there, there's no way the wheel would turn freely.

If you're talking about #10... It's there.

****

I think I know what MAY have been the cause. I've ridden with my gf on the back and the chain was kinda snug. Maybe all the extra weight on the tail putting pressure on the chain over bumps pulled the wheel/axle/swingarm crooked?

I really don't have any other explanation... however, i may need to start hunting e-bay for a replacement. Gah.

Dan

ineedanap · May 20, 2009, 09:32:02 PM

Quote from: Danny500 on May 20, 2009, 09:24:10 PM

I think I know what MAY have been the cause. I've ridden with my gf on the back and the chain was kinda snug. Maybe all the extra weight on the tail putting pressure on the chain over bumps pulled the wheel/axle/swingarm crooked?

I really don't have any other explanation... however, i may need to start hunting e-bay for a replacement. Gah.

Dan

I'm on my second swingarm. My first one was bent like yours but I figured it was crash damage from the PO. That was back when I didn't know .8-1.2 inches of chain slack was too tight for my katana shock and the chain was binding bad on the bigger bumps. Maybe that was what caused my old swingarm to bend too. I dunno

sledge · May 21, 2009, 12:22:32 AM

Quote from: Danny500 on May 20, 2009, 09:24:10 PM
If you're talking about #10... It's there.

Nope.....
its #9 you need to check.....and while you are at it have a good look at the cush-drive rubbers.

VSG · May 21, 2009, 07:45:16 AM

Quote from: ineedanap on May 20, 2009, 09:32:02 PM
That was back when I didn't know .8-1.2 inches of chain slack was too tight for my katana shock and the chain was binding bad on the bigger bumps.

Can you explain this? The Katana shock is stiffer, so wouldn't that mean less movement in bumps and less stretching of the chain?

gsJack · May 21, 2009, 06:12:34 PM

The #9 spacer was missing on my bike for a while. Cush drive bottoms out shifting the sprocket assy in and wheel to the left and the cush bearing and right wheel bearing get a big side load. Discovered it when the right wheel bearing failed, must have lost that spacer during a tire change removing the sprocket assy for balancing.

ineedanap · May 21, 2009, 06:20:52 PM

Quote from: VSG on May 21, 2009, 07:45:16 AM
Quote from: ineedanap on May 20, 2009, 09:32:02 PM
That was back when I didn't know .8-1.2 inches of chain slack was too tight for my katana shock and the chain was binding bad on the bigger bumps.

Can you explain this? The Katana shock is stiffer, so wouldn't that mean less movement in bumps and less stretching of the chain?

No matter how stiff a shock is, you still have to take into account that it will use all of its travel on some bumps.

Bolting on a katana shock (the one I used was an 05 600 and measured 11.75 inches) will raise up the rear. The reason we have slack in the chain is to allow the swingarm to move in an arc. As the wheel moves up and down chain tension changes...usually becoming tightest when the swingarm is parallel to the ground and loosest when the wheel is fully extended. Since the katana shock is longer it changes relationship between the arc of the swingarm (pivot at swingarm bolt) and the arc of the chain (pivot at countershaft sprocket) Since you're basicially setting your slack when the chain is the loosest (fully extended...almost) and still have to account for the chain slack when it's fully extended, this requires a different initial chain slack setting.

Long story short...with a 11.75 inch shock you probably can't use the factory .8 to 1.2 inches of chain slack. You'll probably find that any less than 1.25 to 1.5 will cause the chain to bind over big bumps and limit suspension travel.

VSG · May 21, 2009, 07:35:21 PM

Thanks for the enlightening info! I think in general there's less movement, but you're right, you do have to take into account the maximum suspension travel/arc. Since the kat shock is slightly taller, on the biggest bumps, it will have a larger arc - makes sense now.

Is there a way to tell if the chain is binding over big bumps? Or is a bent swingarm the only way

?

I have a kat shock, but I think I have at least 1.25" of slack. I'll double check that tomorrow though.

ineedanap · May 21, 2009, 08:08:32 PM

Quote from: VSG on May 21, 2009, 07:35:21 PM

Is there a way to tell if the chain is binding over big bumps? Or is a bent swingarm the only way ?

I have a kat shock, but I think I have at least 1.25" of slack. I'll double check that tomorrow though.

I used a really fat friend and a rachet strap to compress the suspension, checking chain slack the entire time. You can also pull the lower shock mount bolt while the bike is on the center stand and manually move the tire thru its travel.

intergalactic · May 21, 2009, 08:10:43 PM

After looking at my bike with a GSXR 600 shock, I was going to mention this. I was gonna tighten the chain, but once I sat on it, lots of slack went away. I have the rear wheel far (all the way) forward in the adjuster slots (came that way) and once I sit on the bike, the slack is about an inch. I haven't check on what it is bottoming.

Quote from: ineedanap on May 21, 2009, 06:20:52 PM
Quote from: VSG on May 21, 2009, 07:45:16 AM
Quote from: ineedanap on May 20, 2009, 09:32:02 PM
That was back when I didn't know .8-1.2 inches of chain slack was too tight for my katana shock and the chain was binding bad on the bigger bumps.

Can you explain this? The Katana shock is stiffer, so wouldn't that mean less movement in bumps and less stretching of the chain?

No matter how stiff a shock is, you still have to take into account that it will use all of its travel on some bumps.

Bolting on a katana shock (the one I used was an 05 600 and measured 11.75 inches) will raise up the rear. The reason we have slack in the chain is to allow the swingarm to move in an arc. As the wheel moves up and down chain tension changes...usually becoming tightest when the swingarm is parallel to the ground and loosest when the wheel is fully extended. Since the katana shock is longer it changes relationship between the arc of the swingarm (pivot at swingarm bolt) and the arc of the chain (pivot at countershaft sprocket) Since you're basicially setting your slack when the chain is the loosest (fully extended...almost) and still have to account for the chain slack when it's fully extended, this requires a different initial chain slack setting.

Long story short...with a 11.75 inch shock you probably can't use the factory .8 to 1.2 inches of chain slack. You'll probably find that any less than 1.25 to 1.5 will cause the chain to bind over big bumps and limit suspension travel.

The Buddha · May 22, 2009, 06:52:03 AM

Well I was talking about #10, but you better not be missing any of them ... you miss any of the critical ones you'd lose a bearing or 3 in short order.
Lose #9 and you'd prolly have to replace the #15 bearing. On my seca it was a 6822 bearing that was a nearly criminal $65 bucks. It has the same OD as the 6302 wheel bearing but a 22mm inner dia as opposed to the 17 or 15 or whatever ... Economies of scale man, economies of scale.
Lose the spacer #13 and you're prolly gonna lose all 3 bearings in short order.
Cool.
Buddha.

Danny500 · May 22, 2009, 05:07:58 PM

All the spacers are there... it's the chain. 100%...

The chain is a brand new DID 520V and the rollers are now loose. I put maybe 200 miles on the chain. WTF....

Ok... new swing-arm is on the way. 1st thing's first... That'll get bolted up... then square up the rear tire... THEN with the upper link disconnected play with chain slack while the swingarm is completely straight.

What a pain in the ass. I just hope I didn't damage my new sprockets.

Time to start ripping sh*t apart again I supoose.

Dan

Danny500 · May 23, 2009, 02:07:55 PM

Just to double check everything before I actually went ahead and changed the swingarm, I stopped into my local bike shop to look at a brand new GS500F... sure enough... my swing-arm is goosed. It is a noticeable 1/2 to 3/4 of an inch to the left of stock.

To double check the chain... I sat on the bike. @ normal sag (32mm) there is less than 1/2 an inch of play in the chain, and the swingarm is no-where-near parallel to the ground.

Then I had my dad sit on it... 290lbs... and bounce... sure enough.. he was bouncing on the chain.

Goddamn it.

**
Funny story though... I actually just got in a 79' Honda CB750K to change the oil and fix a leaky valve-cover gasket for a friend... well, on the side of the bike, near the chain it says "Do not allow MORE than 2 inches of chain slack"....

So I guess I should be running almost 1.75-2 inches chain slack on mine... I'll just have to do the whole range of motion and check everything out first.

Pain in the ass.

joshr08 · May 23, 2009, 04:23:46 PM

1 and 3/4 - 2 inches sounds like a hell of alot of slack to to and i would think on a rebound you could lose the chain. i really wouldnt go over 1.5 in slack but maybe im wrong.

ineedanap · May 23, 2009, 05:15:31 PM

I wouldn't worry about it if you keep it under 2 inches. Lots of bikes have factory recommended specs of 1.5 (older r6 is one that comes to mind) so what's another quarter inch? With my works shock (11.75 inches) I set it to 1.7 (1.65 will bind) and adjust when it gets to 2. Nice and smooth and no bind.

I've had no sprocket or chain issues with the extra clearance. No wear on the sprockets whatsoever and have only adjusted the chain once. I couldn't say that when the chain was too tight!

The Buddha · May 23, 2009, 06:25:08 PM

Quote from: Danny500 on May 23, 2009, 02:07:55 PM
Just to double check everything before I actually went ahead and changed the swingarm, I stopped into my local bike shop to look at a brand new GS500F... sure enough... my swing-arm is goosed. It is a noticeable 1/2 to 3/4 of an inch to the left of stock.

werase643 had a swingarm ... check if he got one ... and you dont want to be riding around with a bent one ... though how its bent determines if it will fail in use or not.
Cool.
Buddha.

Danny500 · May 26, 2009, 11:03:38 PM

Ok, swing arm came in this afternoon and I got right to it.

Comparing the two off the bike... they're identical. I measured X patterns across both, new and old were both 26 and 3/16ths inches from left tip corner of bushing housing to rear outside tip of the right brace... and vice-a-versa... so I don't know what was up...

I checked the bushings in both, they were fine... I checked the spacers and caps on both, still fine... and I checked the swing arm bolt themselves... both straight.

When I mounted the new swingarm.... EVERYTHING LINED UP PERFECTLY AND THE TIRE IS SQUARE!!!!! Woot!

On closer inspection of the old swingarm the left fork is HIGHER than the right fork by about 1/4 an inch... so I think i found the bend... Lol.

****

Other than that, I put the swingarm through it's full range of motion before adjusting the chain... I found I need EXACTLY 1.8 inches of slack in order to keep the chain from binding at widest arc.

Sweet... Sitting on the bike, the chain has about 1 inch, which should be fine for riding without it flinging off, binding, or skipping teeth.

Sweet... Can't wait to take her for a ride...

I also put new seals in the forks, and slapped in new brakes... hooray!

utgunslinger13 · May 27, 2009, 12:14:28 AM

Awesome! Do you think the longer shock and tighter chain were the ultimate cause bending the fork?

News:

Rear wheel off-center, is this supposed to be this way??