Wheel Offsets and Chain Slack

[Power2Go]

It looks to me like the c/s sprocket is NOT offset. But it does have the noise dampener on it. After reading around, some people swear it makes a big difference in reducing noise while others can't tell the difference. I guess that was a Suzuki thing but it looked to me from the diagrams that Yamaha may have done that too. Moot point I guess because it doesn't look like they're available any longer.

The odd thing about my c/s sprocket is that after searching through my tools and actually finding a 1/2" drive 36mm socket, I was worried I'd have to put the wheel  back on to remove the nut. But after I bent over the tab on the lock washer, I discovered the nut was not tightened down at all and I could remove it with finger pressure!

The splines look ok and I can't tell from the teeth whether there was much side wear but that poor sprocket looks like a skilsaw blade! Maybe I can just turn it around and use the other side, haha.

I like the idea of going up one tooth. I really wish this bike had a sixth gear.

The problem I had before with matching up the swingarm marks was that the washer was missing on the left side - there was no way to tell if it was the same as the other side. What I did as a temporary fix was to simply equalize the adjuster bolt length, measured to the center of the axle. Pretty coarse, I know.

The GSXR mod says nothing about needing an offset c/s sprocket so I won't worry about that too much.

More as it happens, Thanks,
(After this is done I think I'm gonna have to Loctite the speedo cable to the speedometer!)

Cliff
'82 R100RS sweet, all the way from SF to Missoula and back.

[Power2Go]

Hah, I just noticed on RPMracing site, he is actually selling NOS c/s sprockets with the noise dampener. Well, taken off re-purposed engines. I would get one but I think I rather like the idea of going up one tooth.

[Urban_Legend]

The GSXR mod says nothing about needing an offset c/s sprocket so I won't worry about that too much.


No it is not needed for the GSXR swap (which I have). Max tyre would be a 170 or 180 depending on brand and it all clear the chain. It may be needed for the EXUP/Thunderace rear arm/Wheel swap as it alows a wider tyre.

Mark

[Pat Conlon]

Mark, I only mentioned the offset c/s sprocket because Cliff posted about a 7/8" wheel offset, i.e. a center line offset between the front and back tire.

If it's just a crooked back rim from mis aligned index marks, no biggie, easy fix, but if is indeed a center line offset, that needs to be addressed and corrected IMHO. 7/8" is much too much.

I know of no other reports of a center line back tire offset with the GSXR mod...at least no one has reported any, and we have a dozen, or so, forum members with the GSXR rear rim.

My question remains: Has anyone with a GSXR rim actually measured for a front/back tire offset?

[Urban_Legend]

I would have to have a look at mine Pat. I don't use the alignment marks. I use straight edges and measurements front to rear.

Mark

[Pat Conlon]

Good deal Mark, thanks!

The swing arm alignment marks are just for making sure the rear wheel is straight.
After you get the rear wheel straight, you need 2 long straight edges to determine if there is a center line offset between the back and front tires.

[X-Ray]

My question remains: Has anyone with a GSXR rim actually measured for a front/back tire offset?

No, and I really should as my bike does pull slightly to the left if I take my hands off the bars. So the bottom line with straight edge measuring is to clamp on both sides of the rear tyre 2 long metal straight edges, have the front wheel pointing dead straight ahead and measure each side of the front tyre to the straight edge? And that measurement should be the same both sides I would assume. For such a seemingly simple procedure I've never completely understood it.

I always check my chain alignment with a Motion Pro aligner,  always thought if it is in line, everything else should be.

[ribbert]

....and I really should as my bike does pull slightly to the left if I take my hands off the bars......

Ray, to which side do you "dress"?

Seriously, just make sure with the straight bars that you clamp them in the centre of the back wheel, equidistant from where they contact the tyre wall, no need to measure, eyeballing it under the axle is close enough. I have mine low because of the caliper then rest them on a couple of paint tins so they intersect the front wheel at roughly the same height. The goal then is as you say, equal measurements front and back, left and right on the front wheel.

This is a terrible photo but you get the idea.



If you need to adjust your chain at some point, as long as you turn the adjusters equal amounts, the alignment will stay near enough until the next tyre change. Not a bad idea to take a measurement against the swing arm while it is perfectly aligned should you need to remove the wheel on a trip or out in the bush.

Noel

[Power2Go]

Thanks to all, Pat, Mark,

I've finally done the work and here are my discoveries and comments:

1) I replaced my countershaft sprocket with Randy's 18T - it works wonderfully! The bike pulls just as well on the lower end and it doesn't feel like it's wound so tight at freeway speeds.

2) I strapped two 16" laser levels, one on each side of the rear wheel on top of 0.5" x 3.5" x 24" flat boards (I'll use pieces of glass next time). I discovered that the difference between measurements at the front of the front wheel and the rear of the front wheel is too small to guarantee parallelness. But the difference on either side of the front wheel is large enough to set the co-linearity of the rear wheel with the front. It's great using the lasers because I don't have to measure. I simply adjust the rear wheel until the lasers match to the same mark on my stick on both the left and right sides of the front wheel. The sprockets are also now in alignment and the chain doesn't make strange noises so what I assumed at first to be a rear wheel offset was indeed non-alignment.

3) I strapped the front wheel to the rear using a cinch strap. This did two things: a) kept the front wheel straight, and b) kept the rear wheel tight against its adjuster stops. This setup, along with the laser levels allowed me to set both the chain slack and alignment at the same time quite effortlessly. Then also, the alignment stayed good while I tightened the axle nut.

It took me days and several tries to finally get this process down but now I'm satisfied with both the alignment and chain slack. The only real tricky part of the whole job was getting the axle and all the spacers in.

The bike truly feels like a new ride! And quite stable and equal in both left and right turns. I can now do the same turns 5-10mph faster than before but it will still take a bit of getting used to.

Before I could even take it out for a test ride though, I had to reconnect the speedo cable - it had come loose again for the second time in a couple hundred miles! This time when I finally got it screwed on I had put a bit of loctite on the threads. Hope that stays for a while longer!

Thanks again guys. And thanks to Randy too.

Cliff