ZX6 to KZ900: Offset Sprocket ?

Hey all,

In accomplishing the measurements provided by StreetfighterKz in a previous post (see below), I come out with a 3/4" offset between the two rear rims (KZ900 vs ZX6 rims).

If its 5/8" or greater difference you'll need a 5/8" offset sprocket and possibly machine the rear sprocket carrier.

Kosman Specialities has an offset of KZ900 up to 5/8" so I'm thinking I still need an 1/8" milled off the ZX6 rear rim sprocket mount... Correct?

Or do I wait and re-measure due to the ZX6 chain is a 530 chain vs. the KZ900 being a 630 chain?

Or do I wait till the motor and rear rim is installed for further and final measurements before any true offsets can be measured and calculated?

NOTE: The bike is presently stripped to the frame (fabrications & painting) meaning the motor is out for any type of measurements...

Thanks,

Old Man Rock



Re:So, which offset sprocket is best for 160mm tire? - 2008/02/02 12:56 Old Man Rock,

All the items connecting to the engine will remain constant. What changes is the position of the rear sprocket. Usually it moves away from the centerline of the frame.

I made a quick diagram to make it a little easier for everyone. Simply take the "blue" measurement and subtract the "red" measurement and that will tell you roughly how far the chain line will move away from the centerline of the bike.

If its 0" to less than 3/8" you might get away with using a stock front sprocket and machining your rear sprocket carrier.

If its 3/8" or greater but less than 5/8", you'll probably have to get a 3/8" offset front sprocket and possibly machine the rear sprocket carrier.

If its 5/8" or greater difference you'll need a 5/8" offset sprocket and possibly machine the rear sprocket carrier.

If its alot more than 5/8" i.e. 1" or so you'll have to do some major engineering because the chain will want to occupy the exact same space as the frame.

Obviously those are just guidelines. You might be able to use a couple washers behind the rear sprocket to take you to the next bigger offset front sprocket but it's kina a case by case scenerio.

Hope this helps.

Later, Doug

Post edited by: StreetfighterKz, at: 2008/02/02 12:57

Post edited by: Old Man Rock, at: 2008/03/02 09:37

What year and model ZX6 did you get the rim from? Also is it 4.5" or 5.5" wide? If its from a late model Zx6R you very well may have to machine the sprocket carrier as ZX rims tend to be wider through the hub area than other brands and models like the Gsxr.

The width of the chain shouldn't really matter in your measurements since the centerline of the sprockets still have to be inline.

The width of the chain will be important when you get your offsets worked out and then have to figure chain to frame and then chain to tire clearances.

Later, Doug

Is that Doug and his brother Doug I here? sorry, couldnt help it(that was actualy Larry i think). u definitly want to get the motor and swingy in there befor u order anything. if u go 5/8" u will rub the frame with a 630 chain. i had to heat the frame and squeese it with a big clamp to gain clearance. what year is you z ? how wide is the rim? i used a zx12 swing and rim . i had to go with a 170mm tire so the chain would clear it. lots of guys go wider but u would need to set the rim off center to do that. hear is my project. feel free to ask anything.
kzrider.com/component/option,com_joomlab.../id,103381/catid,11/

Post edited by: mark1122, at: 2008/03/02 18:29

Oops, my bad! :blink:

1976 KZ900-A4:
Front End: 2005/06 ZX636
Rear End: 2003/04 ZX6R
180mm Tire, 5.5" rim width

Mark1122: Sweet bike!
In reviewing your project, Seems you had a whole bunch of issues to work around that I just didn't think of... DOH! :whistle:

Wait till the motor is in installed based on your replies...Thanks!

Due to the ZX sprocket specs, was planning on the 530 chain anyways so should shave some space there. Hopefully can shave the distance down to 5/8" offset counter sprocket which seems doable and readily available through Sprocket Specialist or Pringles.

170mm tire will most probably be an accurate assessment as well. I don't like the idea of offsetting my rim to compensate...

Question: What changes did you guys have to make to the chain cover?

Mark, I read where you had used spacers but then your shaft was too short and required modifications... There has to be another way.... :woohoo:

Old Man Rock

I cut into an old cover I had to make the extra room. You can sometimes "massage" the cover to gain the clearance without hacking it up like I did. You'll have to remove the sound deadener and the wire mesh that holds it in at the very least.

Later, Doug

Question: What changes did you guys have to make to the chain cover?

Mark, I read where you had used spacers but then your shaft was too short and required modifications... There has to be another way.... :woohoo:

Old Man Rock[/quote]

i gutted the inside the best i could and it was very close.with a 530 chain this may be enough. i desided to put 2 small washers behind ece bolt at the motor side. this shimmed the cover out. then i just had the shift arm cut with a mini grinder and welded back together with the apropriate size rod between. no big deal very easy and chesp fix.
ive been told that the later year sprocket covers have more clearance?? dont know if it is just internal clearance due to no chain oiler and such?

Thanks for the advice guys, much appreciated!

Old Man Rock