Author Topic: 77 cb750 front end swap in progress UPDATED pics and info (Read 15220 times)

epskate · « **on:** February 12, 2012, 09:23:30 PM »

Hey, I am in the process of swapping the front end on my 77 cb750 to a 2005 gsxr 1000 front end. I am using a narrow glide front wheel and I am trying to figure out which rotors to use.

My main question is, how do I figure out what offset rotors are necessary. Any help would be appreciated and pics are going to come soon.

UPDATE INFO: so here's some updated info on the steering stem issue. The original triple tree that I had was bent, so I bought a new one. Turns out that the 2005-2006 gsxr 1000 steering neck is the same size as the 77-78 cb750 steering stem in terms of length. Also, the lower steering bearing for the CB is the same diameter as the GSXR stem. The top bearing inside diameter is too small, so there are two options:

option 1 - you can get a custom bearing and use the gsxr steering nut on top

option 2 (what i did) - put the steering stem on a lathe and milled it down to accept the CB upper bearing and re-threaded the top to accept the CB steering stem nut. So, disregard the picture in the post below of the cb stem pressed into the gsxr lower, as that is not the set up I am running.

I am also unsure of the wind screen....

fastbroshi · « **Reply #1 on:** February 13, 2012, 12:45:26 AM »

StaggerLee did this exact swap.

http://forums.sohc4.net/index.php?topic=58117.0

epskate · « **Reply #2 on:** February 13, 2012, 10:31:34 AM »

great, I'll check it out. thanks

epskate · « **Reply #3 on:** February 14, 2012, 08:48:41 PM »

Well, if anyone is reading this here is a small update:

Vbled1 · « **Reply #4 on:** February 14, 2012, 09:06:51 PM »

I almost did this to my bike but then decided against. Now i have forks, chromed top triple, brakes and an axle from a 2007 GSXR sitting here. I remember reading you could actually just press the cb stem into the gsxr triple with about 12,000 lbs of pressure. How did you do it?

epskate · « **Reply #5 on:** February 14, 2012, 09:16:17 PM »

The hole in the gsxr triple is larger in diameter than the cb neck, and is also tapered. The way I've seen people do it on these forums is by heating up the neck and stretching it with a tapered bit.

What I did was make a shim, welded it onto the neck, and put it on a lathe and cut it down to the right tapered size. Also drilled and tapped the neck and triple on the back of it, so you can't see it in the picture.

Vbled1 · « **Reply #6 on:** February 15, 2012, 01:08:13 AM »

Quote from: epskate on February 14, 2012, 09:16:17 PM

The hole in the gsxr triple is larger in diameter than the cb neck, and is also tapered. The way I've seen people do it on these forums is by heating up the neck and stretching it with a tapered bit.

What I did was make a shim, welded it onto the neck, and put it on a lathe and cut it down to the right tapered size. Also drilled and tapped the neck and triple on the back of it, so you can't see it in the picture.

Damn, nice work. What other plans you have for the bike? Also, axle wise what are you doing?
This link is to a build here on the forum that was done a few years back, it may be of some use even though its a 550.
http://forums.sohc4.net/index.php?topic=34836.0

epskate · « **Reply #7 on:** February 15, 2012, 10:00:01 AM »

That's the build that gave me the idea. I am using the gsxr axle and the gsxr bearings. The sleeve tube that goes over the axle (dont know what its called) is from the narrow glide harley wheel because the gsxr one won't fit in the hub. Here's a mock up of the trip trees and neck on, still waiting for roller bearings.

epskate · « **Reply #8 on:** February 21, 2012, 12:25:26 PM »

well the front end is on. mocked up the stock cb wheel here to see what it would look like

bluesmoke69 · « **Reply #9 on:** February 21, 2012, 09:27:18 PM »

Nice work, I have 1997 CBR front end in my basement just waiting for my 1976 CB750F. Look forward to seeing more progress.

Vbled1 · « **Reply #10 on:** February 21, 2012, 11:53:44 PM »

That thing looks tuff. I like that front wheel too. Maybe because it doesnt have the brakes on it yet.

epskate · « **Reply #11 on:** February 22, 2012, 11:42:34 AM »

Quote from: Vbled1 on February 15, 2012, 01:08:13 AM

Damn, nice work. What other plans you have for the bike? Also, axle wise what are you doing?
This link is to a build here on the forum that was done a few years back, it may be of some use even though its a 550.
http://forums.sohc4.net/index.php?topic=34836.0

Thanks, I'm using the gsxr axle and wheel bearings in the narrow glide hub, with 5mm spacers for the brake calipers and a 320mm suzuki rotor

cben750f0 · « **Reply #12 on:** February 22, 2012, 01:13:41 PM »

just wondering if you are going to register the hub, to accept the discs? or are you leaving them float on the bolts...i would make and adapter to match the harley hub register to the inner diameter of the disc. excellent build btw, love the modern retro look..

peace

epskate · « **Reply #13 on:** February 22, 2012, 02:40:32 PM »

I want to make an adapter like you are talking about, just wondering how to make it stay in place.

cben750f0 · « **Reply #14 on:** February 22, 2012, 03:09:19 PM »

maybe counter sink the holes for the adapter to the hub, so the heads are flush with the adapter, then drill/ tape holes in adapter to mount disc.

is the hub drilled and taped?, if not, might be worth while drilling and tapping another set of holes, so you can screw the adapter directly into the hub. does away with nuts on the other side of the hub, like on the stoke sohc hubs. need to be grade 8 bolts though, with loctite.

im sure someone else will have something different.

peace

epskate · « **Reply #15 on:** February 22, 2012, 03:13:31 PM »

The hub has holes in it that are tapped for the rotor. There is roughly a 13mm gap between the inside of the rotor and the hub, so I was thinking about just making some sort of hub centric ring.

cben750f0 · « **Reply #16 on:** February 22, 2012, 05:41:40 PM »

if you get a chance, take a pic of the rotor on the hub, as centre as you can get it. a top down shot and a side shot, that will give people here some food for thought , and some ideas on possibilities.

gonna looks awesome though...

peace

epskate · « **Reply #17 on:** February 22, 2012, 06:09:09 PM »

Okay, I should get the rotors in a couple of days so I will post up a picture, thanks.

epskate · « **Reply #18 on:** March 11, 2012, 09:42:53 PM »

So here's where I am right now, with the old seat/tail section. New one should be in this week.

The front end is on, no problems. Hub is powder coated, and it should get laced this week.

Here's a picture of headlight brackets made from stainless steel, and the tail light I'll be using, anyone guess what its off?

And here is a picture of the busa rotors re-drilled to fit the hub. Those are hub centric rings in the picture too.

So, here's a parts list for this Frankenstein bike.

CB750
frame
engine/trans
headlight
swing arm
rear wheel

GSXR 1000
Forks
calipers
trip trees
axle

R1
brake master cylinder

Harley Davidson
Narrowglide front rin
V-Rod rear turn signals

'54 Willys Jeep Tail light

Bigsam302 · « **Reply #19 on:** May 21, 2012, 05:09:36 PM »

I have a quick question. What size hub centric rings do you have and where did you get them? I'm thinking about doing the same thing. Thanks!

epskate · « **Reply #20 on:** June 14, 2012, 09:28:13 PM »

Hey, sorry for the late reply. Made the rings, the inside diameter is the size of the hub and the outside diameter of the ring is the size of the hole in the rotors.

wannabridin · « **Reply #21 on:** June 15, 2012, 06:12:18 AM »

Looks cool! That's a unique look, I'm digging it! Cool paintjob too

robbins · « **Reply #22 on:** August 01, 2012, 10:46:31 AM »

Hello im new to this forum. Im currently doing this gsxr frond end myself. I was hoping someone could provide me the specifics of the harley spoke wheel used and how. The posts do discuss this, but not in specifics of year of wheel and Bering swap narrow glide did change there wheel throughout the years. also is it as simple as pressing out the old bearings and pressing in gsxr bearings?

Thanks

epskate · « **Reply #23 on:** September 06, 2012, 05:34:45 PM »

Hey, I'm not exactly sure about the changes in years for the narrow glide front hubs. I remember reading a while ago that one generation of the front hubs was 1/2 an inch thinner then the other. You would probably just have to add a spacer. General specs of the front wheel you want: 19", 40 spokes, dual disc hub.

As far as the wheel bearings go, yes all you need to do is press in the gsxr bearings in. The outside diameter of the gsxr bearings is the same as the harley ones, the difference was the inside diameter.

Now, I have a question and I'm hoping someone can help me. I am looking to change up my front wheel and go down in size from a 19 inch to a 17 inch. Does anyone know of a bike that came with a 17 inch, 40 spoked front rim? Ideally something around a 17" x 2.5" Thanks

ACP1 · « **Reply #24 on:** November 16, 2012, 05:52:05 PM »

Hey. Lots of usefull info and a very nice bike. I am doing a similar front end swap on 78 CB750f. I am confused about a couple of things though. I am using an 05 06 gsxr1000 front end as well (at least I think it 05 06 It has red caps black inner tube much like the one on your pics). The steering stem length however was a 1/2 inch shorther than the CB. So I had one machined 1/2 inch longer and it seems like a good fit now. But I can't wrap my mind around the fact that you say yours was the same length. The next thing question I have is regarding the narrow glide hub. Did you only use the hub or the entire rim? My next step is getting the busa rotors and coming up with an exceptable solution for adapters. I was hoping that you could provide some close ups of your setup including the damper. Thanks in advance.

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Author Topic: 77 cb750 front end swap in progress UPDATED pics and info (Read 15220 times)