5/8 offset sprocket clearance issues

Well my project is mocked up, after putting the offset sprocket on I realized I needed to clearence the frame a bit, used a grinder to flatten the welds a bit and a porta power to strech the frame out a bit, get it all togeather and it still rubs!! I'm running a 17x6 zx9 wheel with a 180 tire, I have no issues with tire clearance just with the frame, the chain is in line and the wheel is centered, I guess I need to just heat and beat, any other suggestions???

Never done this myself, but guys I know have just heated up the frame in the area where the chain rubs the frame and uses a hammer to flatten the frame as much is needed for clearance. I have seen a couple bikes where they have cut the frame and removed the area needed and put in a piece of channel iron but to me, that seems to put a weak spot in a critical area. Mostly I've seen some frame manipulation with a hammer in the area.

Going through this myself... (KZ900)

Just ordered today as a matter of fact from kosman Specialties a 1/2" offset counter sprocket versus the 5/8" for this exact same reason, FRAME clearance.

With this, I'll have the rear ZX6RR hub milled down and most likely end up with a 170mm tire versus the 180mm installed on the rear rim. Really won't know until I get the CC sprocket installed and verify all the clearances and other possible options.

The ZXRR uses a 520 chain and in using the same rear sprocket layout of a KZ750 (1976-1979) I'll have to upgrade to a 530 to get this all to work... I just can't find anyone that manufacturers a 520 CC sprocket (1/8" thinner in the width) for KZ900. Only 530 or 630, mostly 630 only...

Ah well, that's what makes this all fun... Yeah right! I'll be too friggin old to ride the damn thing by the time I get it done...LOL!

Good luck and let us know what you end up with and how it worked out...

Old Man Rock

Go to the JT Sprockets website, their catalog lists the dimensions for all the sprockets (spline count, etc) and find the dimensions of the sprocket for your motor. Then just check the dimensions of the sprockets for other bikes till you find one in 520 that will fit your bike.

A lot of Suzuki sprockets will fit on the KZ output shaft.

Hey steell,

"Then just check the dimensions of the sprockets for other bikes till you find one in 520 that will fit your bike"

Yep, been there numnerous times from your link (thanks, awesome site) doing exactly as mentioned but I do have some reservations about using the 520 on a KZ900.

I realize chain tensile strengths have increased but most 520 chains aren't at the 10,000lb specication I think that would be required for the high torque of the 900 motor whereas 530 (EK-530ZZZ) do for example. Wouldn't excessive chain stretching become quite apparent in a short time, unknown but possibly.

Also, in using a comparison sprocket with same dimensions/spline, you'd still be faced with the offset issue due to wider swingarm/rim/tire. I've reviewed postings where others have welded two CC sprockets together and such but I'm just not comfortable with that. Would it work most definately but for $60, why not just get an offset designed and built for it.

BTW all, the guys over at Kosman are top notch. Easy to work with, responsive, paid for the shipping and even offered to build me a rear sprocket to my specs for $60-80 pending tooth count. I ordered a 1/2" offset 15 tooth (to match the stock gearing) $60 total. All in all, I was impressed and that's not easy to do. lol!

Old Man Rock

my bike is a 530 setup, but as far as going to 520, alot of the new 1000cc sportbike riders convert over to high quality 520 chains/sprockets from 530 or 525. to put it in perspective, these new bikes make around 160+ hp stock, 80ft lbs of torque, and they dont seem to have any trouble goin 10k miles b4 replacement.

it takes a pretty stout kz or z1 engine to replicate those numbers and still be streetable...unless you go turbo/nitrous

off topic but where did you get those foot controls ??? That exaclty what i need !!!

How much are they

Chopperdaddy wrote:

off topic but where did you get those foot controls ??? That exaclty what i need !!!

How much are they

They were mad by me, based off of some zx9 parts..

I still have not seen anywhere a 520 or 530 5/8 offset with the bearing support.

What about these guys (PMFR): www.pmfronline.com/counter_shaft_sprockets.htm

Or these guys (D&G): www.dgchassis.com/


btw: GREAT JOB ON YOUR BIKE!
-KR

can i see a pic of the other side ?? plz ??? i my make something like that myself !!!

Chopperdaddy wrote:

can i see a pic of the other side ?? plz ??? i my make something like that myself !!!

here you go:

I am running a 1996 zx9 17x6 rim on the back of my 77 kz1000 with a 5/8 offset sprocket in the front. I have no rubbing issues at all. However there is a hair of space between the frame and the chain. I had to machine the sprocket carrier 1/2 to get the chain line to be straight with no rubbing. Make sure that the back of your sprocket is flat i have seen one sprocket with a tine lip on it which can be machined off. Also behine the sprokcet is a spacer you can change that if you need to. ALmost forgot i am running a 530 chain is yours a 630??