Topic: Rear axle width?

[SOHC Digger]

So upon further inspection, the width for the rear axle on my hardtail frame is about 9 1/2" wide.  The swingarm for my '78 750F is about 10 1/2" wide.  So, this frame won't work for me without modification.  My question is did Honda change the rear axle for the 77 and 78's or is this frame just not for a CB750?  The engine mounts are correct, but maybe it's for another bike altogether?

[Ricky_Racer]

Can't you just cut down the spacer? Where are you in Illinois? I'll be out there in December. RR

[SOHC Digger]

I don't think I have room to take a 1/2" off each side and still have chain clearance.  I am near Joliet, IL.

[MCRider]

I don't know for sure...but that's too good of a start to freak out. Any good machine shop can put a wiggle into that frame to make it work.

Maybe the later wheels are wider with all included. You don't really want Comstars on a chopper do you. 

[SOHC Digger]

I like the Comstars cause they're different, but I'm willing to give them up.  What I want though, it the dual disc up front and the rear disc on back.  I am going to take a closer look and see what I can take off and still have chain clearance.  Maybe I can convert to a 520 chain setup instead of the 630.

[KingCustomCycles.com]

77 and 78 are wider as you have found.  Most chop kits were for the 9.5" spacing.  It can be spaced properly and still clear the chain.  I have done it roughly 7 times.  It is just part of the differences I have to remember when using assorted year parts on my Bobbers. KingCustomCycles.com for pictures.

[Ricky_Racer]

Digger, there are two different interchangable rear drive flanges for your rear wheel. The '75-'76 has less offset than the '77-'78 by 10mm (20mm?), if I remember correctly.

BTW, I'll be in Bloomington and Morris through most of December. RR

[KingCustomCycles.com]

And the drive hubs can be swapped with no issues to compensate for that width difference.  I had to do that on my last Amen's Savior Plunger frame.

[SOHC Digger]

Thanks RR and KKC!  Where can I get the other drive flanges that you speak of?  Can you give me a little more detail as to what needs to be changed in the process?

[KingCustomCycles.com]

Stand on the rim and pull number 11 out of the hub.  Slide the narrower one in, done.  Someone else will know what years and models were wide or narrow in that area so you can shop for what you need.  I just know they swap with no changes. 

[SOHC Digger]

Stand on the rim and pull number 11 out of the hub.  Slide the narrower one in, done.  Someone else will know what years and models were wide or narrow in that area so you can shop for what you need.  I just know they swap with no changes. 

And will this still keep the wheel centered in the frame?

[KingCustomCycles.com]

The carrier will narrow the hub and then proper spacers will center it.  I like to use old oem spacers from other bikes.  The ID and OD are right and it is a simple matter of cutting them to length. Cycle recycle 2 in Indianapolis has a large box of used spacers Rob will sell cheap.