High ratio primary gears

Packrat said:

I am looking for a set of high ratio primary gears for an upcoming road racer project. I emailed Ivan Hoey down under and it sounds like he has some in the works but may be a while before they are ready. It dawned on me that I may not be the only Packrat in the group so if anyone has a set sitting around or a used set that were taken out for some reason let me know what ya got! I’m doing a wheel swap and trying to get into an off the shelf sprocket range for a GS500 wheel. I think with a high ratio set and 18/40 sprockets it should be close. Smallest available for that wheel is 39 tooth. I drew up a 33 tooth sprocket in CAD today to fit the GS Cush drive to get one water jet cut but until I get one cut I’m not sure it will work! Besides, a bigger sprocket would get me some additional swingarm clearance!
Thank

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Dunc said:

I've ordered a set as well. Running 17" CBR 600 wheels & the OD is a fair bit lower. I don't think 18t front sprocket will do the job either. I'm going to run a 520 chain with 36t rear sprocket.

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gggGary said:

GS500 rear wheel with a RebelGears aluminum sprocket. Think it's 32 tooth, no problem clearing the hub but that's about the lower limit of tooth count..
Ended up cutting a recess in it so the stud nuts would clear the radian swing arm. Might have skivved a little off the drive flange for sprocket alignment.

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Packrat said:

Your build looks great! What is that swingarm and suspension off of? That looks tall enough to give chain clearance problems even at 36T! I love the look though.

that’s great info. How did the gearing feel and did you go to a 18 front? 520 or 530 chain?

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gggGary said:

17 32, still just a shop rat bike. but with the 17" wheel should be fine.
Swingarm is radian.
https://www.xs650.com/threads/ywain.55701/

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Dunc said:

Thanks! 2001 YZF600R swingarm/shock & 2003 CBR600F4i complete front end with the CBR wheels. Airtech Moriwaki Endurance racer seat. I want to build something a bit different from the Tracker/Bobber/Brat stuff.

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Packrat said:

That’s the way I feel too. I’ve built a bunch of trackers and love them but I’m trying for something a bit more mountain road worthy this time. How much did you have to do to the yzf600r swingarm to get it on? Is the pivot width the same?

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Dunc said:

I had to shorten the pivot 10mm each side & remove 8mm per side inside the frame. I believe the earlier YZF arm is much closer to going in but I like the look of this one. I need to give the inside of the frame a little tune up with a blue flame spanner to get full travel.

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Dunc said:

I had to shorten the pivot 10mm each side & remove 8mm per side inside the frame. I believe the earlier YZF arm is much closer to going in but I like the look of this one. I need to give the inside of the frame a little tune up with a blue flame spanner to get full travel.

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