1978 CB750 Cafe build second attempt

downtown809

downtown809

Trying to keep out of trouble
With spring in the air and my CX500 so close to completion it was time to secure my next project, it is a 1978 CB750. Will the cx500 comstars fit this bike as I prefer them to spokes?
2013-02-24_13-41-03_175_zpsaa235744.jpg
 
Um, no. The CX500 is a shaft drive. How would you put a shaft drive rear hub on a chain drive motorcycle?
 
Ok Alphadog you have made a good point. The Hondamatic wheel is the wheel but they are so proud of them on Ebay. Next step is to see if the local wrecking yard has any.
 
Shaft drive is so frustrating because modifications are such a substantial engineering challenge.
 
Most guys want to swap their Comstars for spokes so I bet if you are patient you could find somebody to swap you even up! :)
Probably totally wrong here but... I think 78 was the first gen to get Commies, but only on the A's and the F's. Assumeing yours has rear drum, I see it has a single rotor front. Don't know if you could mount a single rotor on the front wheel off an F or not, If I remember right the single rotor has 6 bolts while the dual has 5 ::) .... other wise you would need F lowers to get the right side caliper mount...Maybe pick up a complete F front end and get dual rotors. Of course that would mean dual calipers, lines, splitter, and master cylinder would be needed as well.

This guy is trying to sell a set... http://mijola.com/vehicles/motorcycles/sohc-cb750-comstar-mag-wheels_i61437

61429.jpg
 
2013-03-02_07-51-16_711_zps373f9f25.jpg


So tires were on sale, just like everything at Jos A Bank if you haven't heard so I got hooked up with a set of Spitfires, stock size of course.
 
Thanks for the tip Hoosier Daddy, I contacted the seller, he still has them and it is a good thing as some of the spokes have elongated their holes in my current rear hub.
 
downtown809 said:
Thanks for the tip Hoosier Daddy, I contacted the seller, he still has them and it is a good thing as some of the spokes have elongated their holes in the rear hub.
Click to expand...
surprised.jpg
I knew the early Comstars had a recall for the rivets coming loose back in the day.. but that is the first set I have actually heard of that had the issue WOW! Good news is he was honest enough to tell you about the elongated holes.
Your not missing anything, definately a rear drum in the pic, that why I chose it. So either the seller is wacked or they aren't his wheel pictured. Just shows you they are out there.
Like I said though, MANY want to swap their Commies for spokes so I bet you can find a good set pretty easy, maybe trade even up if your lucky. Check out some of the dedicated CB750 forums, I and a couple others here are on CB750-s but it's a small forum just getting started, there is larger ones out there with more members to get more contacts.

You like Lars' (Octane's) Goldwing eh? His "Bulldog" has inspired many a bobbed 'Oldwing project including my "Bomber"! 8)
 
Love that Goldwing.
As there are purists who might be reading this I will mention that I purchased both bikes I am modifying as non runners for $300 and $400 respectively.
I didn't hack up the GS1100E as I can't bring myself to cut up such a beautifully preserved piece of history, I target nice shape projects that have one foot in the grave as it were.
I am not sure if I will derive as much pleasure riding either bike as I do tearing into and then rebuilding as I see fit.
 
Question on front forks: Here is a picture of the left fork with caliper.
2013-03-03_17-33-42_542_zps16d38efb.jpg

Here is a picture of the right fork.
2013-03-03_17-33-24_145_zpscdeb126d.jpg

Are these dual caliper forks and do they look like your 1978 CB750 forks or have they been swapped out?
 
As I am committed to keeping this a roller until the CX is done here is the progress: Frame cut,
2013-03-03_17-31-23_665_zpsc3c29f84.jpg

Brackets coming off,
2013-03-03_17-14-41_408_zps9b7f259c.jpg
 
The old farmers adage, "measure it with a yardstick, mark it with chalk, and cut it with a torch" is slightly modified in my garage to "measure with a tape, mark it with sharpie, cut it with a reciprocating saw and shape it with an angle grinder". If it requires more than this it is hired out.
 
Hoosier Daddy said:
Most guys want to swap their Comstars for spokes so I bet if you are patient you could find somebody to swap you even up! :)
Probably totally wrong here but... I think 78 was the first gen to get Commies, but only on the A's and the F's. Assumeing yours has rear drum, I see it has a single rotor front. Don't know if you could mount a single rotor on the front wheel off an F or not, If I remember right the single rotor has 6 bolts while the dual has 5 ::) .... other wise you would need F lowers to get the right side caliper mount...Maybe pick up a complete F front end and get dual rotors. Of course that would mean dual calipers, lines, splitter, and master cylinder would be needed as well.

This guy is trying to sell a set... http://mijola.com/vehicles/motorcycles/sohc-cb750-comstar-mag-wheels_i61437

61429.jpg
Click to expand...

That was my ad- I made a mistake on there- the rear wheel is a DRUM brake setup. I talked to you on the phone yesterday! Small world, eh? So anyhow, I will get you that shipping quote tomorrow if you still want
 
So I wonder why the rear brake wouldn't work?
2013-03-03_21-03-24_137_zps38362212.jpg

The good thing is that the drive has 4 splines. What do they call the pieces of rubber that act as shock absorbers in the drive hub?
 
downtown809 said:
Are these dual caliper forks and do they look like your 1978 CB750 forks or have they been swapped out?
Click to expand...

It's quite common to have unused caliper mounts on a bike's forks.
 
So I wonder why the rear brake wouldn't work?
Click to expand...

Wow! I'd say you're lucky it didn't lock up... DAMN!

The good thing is that the drive has 4 splines. What do they call the pieces of rubber that act as shock absorbers in the drive hub?
Click to expand...
Factory term is dampers, but commonly known a "cush (coosh) drive" around the net.
 
Thanks Matt for the wheels, Thanks Alphadog for the heads up and yes Hoosier Daddy, he was lucky..
 
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