Comstars + gsx-r front end

rs_ss350

Active Member
I'm one of the rare few who actually like the look or comstars for my project, but wondered if there's a way to use them with the gsx-r fe I just bought. If not I'll have to settle for different wheels but wanted to check before committing.

Btw, this is for an 82 cb750

Thanks!
 

J-Rod10

Over 1,000 Posts
DTT BOTM WINNER
Spacers and rotor adapters. Easy work, if you have a mill and a lathe at your disposal. Probably a couple hundred if you don't.
 

cxman

Over 1,000 Posts
DTT SUPPORTER
first one i did cost me over 500 due to the thickness and sizeof the blanks plus axle spacers and bearings and seals ect











i also found since that using rotors from a honda black bird will require way thinner spacers

and more or less right up to the comstar you have to weld redrill the moount holes the rotor comes with 6 holes and the comstar 5

http://www.ebay.com/itm/97-Honda-Blackbird-1100XX-Front-Brake-Rotor-75E-/152140998673?hash=item236c4f6811:g:JuUAAOSwzJ5XYf5w&vxp=mtr
 

rs_ss350

Active Member
Thanks guys - glad to know it's possible (anything is possible). I don't have the engineering skills myself to do this but have friends. I can turn a wrench like a monkey though. Can you give me the specs for what you did? I have gsx-r rotors already, so i guess the measurements would need to be a bit different than what you have. Couple hundred would hurt me a lot less than cobbling together a laced wheel with cognito parts so I am very into this.
 

rs_ss350

Active Member
What's needed as far as the axle? i haven't attempted to size them up yet before deciding if it's even possible
 

crazypj

Split personality, I fake being smart
Personally I would bolt them on using original mounting holes just use one extra long bolt (if any rotor holes line up)
Honda spent a LOT of time and money 'fixing' the Comstar's. The original wheels with cheap 'stainless steel' (they go rusty) 'spokes often loosened up requiring new wheels under warrantee (I was running a workshop at Honda dealers when the various new 3~4 valve motors and Comstar wheels were launched)
 

rs_ss350

Active Member
OK, so i found that Ninja rotors line up almost perfectly with the honda 5 holes. the question now is what thickness of spacer i'd need to get the rotors to line up with the calipers...

and then, what's the solution for the axle? The GSX-r is 25mm, the original is 15mm. Is there a bearing that's going to work in there? then a 25mm diameter spacer between them?

THanks!
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
What I've done is go somewhere like Motion Industries and found a bearing with the right OD and ID and swap them out. When there wasn't a bearing option, then I've made a tension bushing to slide over the smaller diameter axle to fit the larger diameter forks.
 

rs_ss350

Active Member
ah - tension bushing - that's interesting! so they'd go in the wider diameter fork "clamps", while the rest (axle, bearings) is oem. you got a picture of it installed i could use for reference? still learning here.. :-[
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
I don't have a pic installed where you can get a great look. This is what the bushing looks like:
Bushing.jpg


I was putting a KZ750 front end on a Honda CB750 while using GPZ rims. If you look close, you can see the sleeve in there.
fea45dd8be98391b42b23c2a292326de.jpg
 

crazypj

Split personality, I fake being smart
I made alloy 'bushing' for Neevo to fit GSX-R forks with stock CB400 front wheel. Probably safer to bush the fork legs and use a GSX***F front axle (15mm) I used Katana 600/750 axle. The bigger issue, how much shorter than the stock forks are GSX-R forks? Usually, it's around 2"~4" difference which will really mess things up (unless you lower rear to match but then you run out of ground clearance real quick)
 

rs_ss350

Active Member
thank you!

So the Comstar bearing has 42mm OD and 15mm ID, with 13mm width. The GSX axle is 25mm ID, so I found an All Balls bearing that's 42mm OD, 25mm ID, but it's 9mm wide. Will the narrower width be a concern in terms of performance/wear-tear? And if not a concern, I assume the spacer inside the hub will need to be 8mm wider to make up for the space difference, then we should be all good?
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
I wouldn't worry about the 4mm difference. And yeah, you'll need the spacer to make up the difference.
 

crazypj

Split personality, I fake being smart
That's a nice easy way to do it, those bearings may not have been available a few years ago?
Do you have spec for load ratings, etc. (although I doubt you'll exceed limits?)
 

rs_ss350

Active Member
http://www.allballsracing.com/6905-2RS.html

There's no specs out there on the site. But thanks for confirming this will work along with the spacer. Now for the spacer, I assume I'd want the ID of the spacer slightly larger that the axle? How many mm clearance should there be?
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
You want a slide fit. Not tight, but not loose either. Essentially, OD of axle should match ID of spacer.
 

DTT Bike Of The Month Gallery

DTT Light or Dark

www.jadusmotorcycleparts.com
shop.themotoworks.com
www.cognitomoto.com
https://www.townmoto.com
www.speedmotoco.com
www.lostapostle.ca/
www.sparckmoto.com
Top Bottom