Topic: GL1000 front end swap. Can I re-use my CB750 front wheel?

[SOHCiro]

Hello,

I know there's been discussions on several different forums regarding this topic, but the information varies quite a bit and wanted to double check here with people who's done this mod. I know they're longer than the CB forks, and they're stiffer as well. I've already tried the dual disc set up on the stocker, and want to have better braking power with more rigid front feel with right-side up forks.

I'm getting a killer deal on 1977 GL front end, but without the front wheel+rotors.
Although the aluminum GL wheels are way better, I don't wanna have spend $150+ for the matching wheel, rotors and new bearings, since I've just rebuilt my CB front wheel.
From what I've gathered, the forks and triples will bolt right onto the CB750 neck, and the CB wheel CAN be reused, but only with the GL axle+spacer+speedo drive. Is this correct?
What I'm confused, is that some people say that CB rotors have a different offset from the GL ones, and cannot be used.
And the speedo drive on the GL is located on the left side, as opposed to CB on the right. Does the GL speedo drive still work on the CB hub on the right side, or do I flip the front wheel, switch the direction of the tire to have the drive on the left side??

Thanks in advance

[CB_Jeff]

I believe the front wheel hubs are the same for the early GL1000's and the 750's, the difference is the rotors that bolt-up to the hubs.
So the wheel should work, but you will still need to look for the GL1000 rotors and calipers / caliper hardware. 

[Bankerdanny]

CB_Jeff is correct about the rotors.

Regarding the direct bolt on, I believe that you need to swap the steering stem from the 750 tree because the GL1000 stem is too long for the 750 neck.

[seanbarney41]

Regarding the direct bolt on, I believe that you need to swap the steering stem from the 750 tree because the GL1000 stem is too long for the 750 neck.

nope, the whole triple bolts right up, stem, bearings and all

[Bankerdanny]

Regarding the direct bolt on, I believe that you need to swap the steering stem from the 750 tree because the GL1000 stem is too long for the 750 neck.

nope, the whole triple bolts right up, stem, bearings and all

Must be the 550 I am thinking of.

[SOHCiro]

Thanks for the replies!
So I guess I should start looking for decent early GL1000 Rotors...
Has anyone got thoughts on the axle+ speedo drive compatibility?

[dusterdude]

I know 75-76 are the same,I believe 77 and later are different.I could be wrong

Sent from my LG-US601 using Tapatalk

[seanbarney41]

you have to use the axle, spacers, and speedo drive from the gl

if the gl frontend came from a bike with comstars, you have to use the comstars (not sure about 77...either 77 or 78 was first year for comstars)

as far as brakes go, I have a cb750 with the gl swap and a 78f master cylinder, and I have a cb750 with the traditional dual stock discs and a Suzuki Bandit 16mm master, and the traditional dual disc with Suzuki master will out brake the gl stuff every time.  So, if you are planning this swap just for the brakes, I would not recommend it.

[tlbranth]

You're probably set on doing this swap but let me throw some info in here which I'm sure will get me some flack. I have a '70 CB750 and a '75 GL1000. The brakes on the GL suck - especially the back brake. Yes, I've done all the kits and all the rebuilds but my CB750 has waaaay better brakes than the GL. Its single disk outperforms the dual discs on the GL.

[Bankerdanny]

78 was the first year for Comstars on the GL1000

[low-side]

I am putting a GL1000 front end on my 750 project.  It will have a twin piston caliper conversion, cartridge fork emulators and a fork brace.  I have a 78 GL and I agree with several previous posters that stock GL brakes lack feel and power.  The front brakes on a first gen 'Wing are the worst feature on an otherwise great motorcycle.  My last 750 project had the standard twin disc conversion with emulators and a fork brace and was stiffer and stopped better than a stock GL1000 fork.  All that being said, I would get the GL axle, rotors and spacers and build it like you were planning to.  If you like it, that's great.  If you don't, you can upgrade as time and budget allows.  Have fun with it!

[seanbarney41]

that is very interesting...a stock gl1000 weighs about 100lbs. more than a cb750?  I certainly think the gl swap brakes better than any stock cb750 I have ridden (with the exception of the 77/78f, but who would use that with an ugly comstar?lol)

low-side...those are good comments. thanks

[SOHCiro]

Thanks all for the valuable input!
Pretty shocked(no pun intended) about how you guys feel about the gl brakes, now I'm not so sure if I wanna do the swap haha.

On a side note, I just happened to pull up next to a newer Yamaha R3 today and we did a few straight line comparison.
Having known that the yammy is about half the weight of the CB with 40+HP, I was pleasantly surprised that up to about 50mph on my speedo, the CB was way ahead. Really important to keep it above 7000 rpm, and the short shifted 4th gear was pulling me down. Nonetheless, the old gal can still keep up with young ladies, some confidence boost right there.

[scottly]

The twin piston calipers low-side mentioned are a great upgrade from any of the sohc or GL single piston calipers. There is a thread about this in the brake area of tips and tricks, but using the 750 F2/F3 forks. To use a  750 spoke wheel with either the single piston F2/F3 or GL calipers, you will need to use smaller 275mm rotors like from a 550, and with the 2 piston calipers the 550 rotors will have to be thinned.

edit: here is a link to the thread:
http://forums.sohc4.net/index.php/topic,89771.0.html

[SOHCiro]

---scotty
That sure sounds good but costly and more time consuming than the GL swato look for stem bearing, rotor machining, and the calipers all for a good deal.
I might as well wait it out till winter, cause motorcycle parts tend to come with much higher price tags right around this time of the year

[seanbarney41]

If the gl calipers you are getting need rebuilt, you are looking at about $150...then new springs and possibly tubes...that free or cheap gl front-end ain't so cheap no more.

[1976cb750f836]

If you use the suzuki(ive done this master conversion on my 76f with 78 dual disc, and also on a 77 wing), master , available on eBay (Under 1981 gs 750 search), (their cheap, under 30$),it will Greatly improve the front braking. I own a 81gs, and got to wondering why the brakes were so much better, measured the gs master and mount, bought 1 to try, and was amazed how much better they work, no more wooden feeling when u pull the lever. Its a bolt on except for switch wire ends have to be moded . I believe it was a 15mm(instead of a 16 that was mentioned eariler), anyway its the 1 for 81 gs750.

[Bankerdanny]

I am putting a GL1000 front end on my 750 project.  It will have a twin piston caliper conversion, cartridge fork emulators and a fork brace.  I have a 78 GL and I agree with several previous posters that stock GL brakes lack feel and power.  The front brakes on a first gen 'Wing are the worst feature on an otherwise great motorcycle.  My last 750 project had the standard twin disc conversion with emulators and a fork brace and was stiffer and stopped better than a stock GL1000 fork.  All that being said, I would get the GL axle, rotors and spacers and build it like you were planning to.  If you like it, that's great.  If you don't, you can upgrade as time and budget allows.  Have fun with it!

GoldWing guru Randakk argued that the only problem with the GL's brakes was the master cylinder was not correctly sized. He recommened a 5/8 master, which I believe is a slightly smaller piston than stock. When I did my F3 front end swap this year (the F2/3 use the same front calipers as the GL1000), in addition to getting my rotors thinned and drilled I installed a Nissin 5/8 radial master (~$140). I have no complaints regarding braking power and they got a very good workout during my trip through Tennessee, Kentucky, and the Carolina's earlier this month.

[scottly]

Yes, the 11/16"(17.5mm) master cylinder used on the 750 F2/F3 and GL with dual 38mm calipers was WAY too big. Tons of earlier dual 38mm caliper 750K conversions were done with a stock 14mm MC. 5/8" is 15.875mm,  but a 15mm would be closer to "ideal" according to the Vintage Brake chart.