Topic: 180 in a DOHC 750 Swingarm?

[Turbogrimace]

I know some of you guys are running 180 rear tires, but a lot of you have different aftermarket swingarms.  I am trying to slip one into a DOHC 750 swingarm.  Does anyone have any experience with this?  Any tips, tricks, advice?

What to I need to mod to squeeze the rubber in.  Im running an SS 750 hub with disc.

Thanks!

[Geeto67]

I don't think you will get a 180 in a stock frame without a jackshaft. You can do it with a chopper frame but I think you need to do frame surgery, I am not sure the chain line will clear the rear frame rail. I know the chopper guys use the 78 motors because it gives you the most chain spacing with minimal offset.  I think a 160 might clear, most of the cb issues on a stock bike have to do with the tire rubbing the stock swingarm.

as far as getting a 180 in a DOHC rear swingarm, I would suggest looking at a cbr600 f3 rear rim. I am not 100% sure on this (I am for the cbrf2 but that is a 160) but I believe the rear axle diameter is the same as a stock DOHC cb750F so all you would need to do is make spacers to fit and figure out how to do the chain line. Otherwise you will need to lace a 5" rim to your cb750F hub.

Honestly though, why do you want an 180? 150 will provide you with all the traction you need if you are going racing. A 180 tire is pretty useless on a cb750.

[Turbogrimace]

This is for an aftermarket frame and Im needing to run a wider rear fender to maintain good proportions for the bike.  Im going to lace a larger rim to the hub.  Some of my concern lies in the chainline because my motor is a 70.  Im not sure if Cycle x's offset sprockets will remedy this.  I dont want to have to move the motor in the frame either.  Im being really picky haha.

[Geeto67]

This is for an aftermarket frame and Im needing to run a wider rear fender to maintain good proportions for the bike.  Im going to lace a larger rim to the hub.  Some of my concern lies in the chainline because my motor is a 70.  Im not sure if Cycle x's offset sprockets will remedy this.  I dont want to have to move the motor in the frame either.  Im being really picky haha.

the cycle-ex sprockets are specifically designed for this application. you will need their offset motor sprocket, plus a 78 sprocket carrier and a smaller offset in the rear. If you call ken at cycle ex he will set you up with all the parts needed for the proper chain line (and he sells the wide rims too). It is pricey but if just about they only way to do it without getting a 77-78 motor.

[Turbogrimace]

Ill give Ken a shout, but has anybody modified a DOHC swingarm to fit a 180?

[Geeto67]

Ill give Ken a shout, but has anybody modified a DOHC swingarm to fit a 180?

What exact year swingarm? 1979 might be too narrow all together and you would have to widen it, 1980+ should be able to take a 180 (it will be tight but it fits). To be fair all of the 180 rear tires I have seen on DOHC swingarm have had that swingarm streched 2 inches.

[Turbogrimace]

It's an '80 swingarm.  I saw someone on the hondachopper board with a 180 in a DOHC swingarm that looked like it had minimum to no modifications.  If anything I only noticed the stamp weld near the front of the swingarm ground down.

[dusterdude]

my f3 has a 170 on it,but i think a 180 will work.