Dad’s old <edit>71 750four

[Westfalia]

I am now the owner of my dad’s old ‘71 CB750 four. This bike is all there but VERY rough and not a runner. It has sat outside under various states of cover for about 30 years minus it painted bits which were thankfully stored inside. Currently its under cover and secure.

Eventually I’ll give it a proper resto maybe once retirement happens…lol. 5-10 years…maybe. So to my question:

What should I be searching/collecting for now that might not be there in the future?

I’ve not done a detailed “needs” list so i can’t really say what will need replacing, but figure rubber/lines/controls will all need replacing. I do have the OG exhaust and guards but they have a few holes. Are some things on the bike “unibtainium”? I come from the vintage VW world and as values have come up a huge amount of reproductions parts are now available compared to even 10 years ago. Is the bike world similar?

Pic is of my dad on it in the 70’s when he used it as a daily commuter. Miss ya pops.

Thanks for any help!

 

[gunr]

Hi Westfalia,
I have a few 750's, the oldest is a 73.
Being exposed to the elements can be real bad for a motorcycle. All rubber parts are probably shot. Rust is the culprit that freezes pistons, swingarms, cables, gauges, ruins wheels etc...
Four into one is my go to for maintenance parts for mine and they're out of California so at least you have that.
Try turning the motor over with the kick starter to see if the motor is frozen. That will determine the level of work ahead of you.
The 1970 model is only one year from the first sandcast model and that makes it more valuable. I had a chance to buy a '69 years ago and didn't and I'm still kicking myself.
I did just acquire four 750's and a 450 from a relative so I've been wrenching more than I have in years. Retirement is good.
Good luck in your journey!

 

[Westfalia]

Thank you for the reply. I’ve now realized that this is a ‘71 and not a ‘70. I’ve edited the title.

I’m pretty sure it is locked up and it will need an entire resto. What are the hardest parts to find or are they all HTF? Everything is there, but it’s all roached. Is there any value in that Windjammer faring and fiberglass box/ and rack? I never liked the look of either of them, but he loved them for commuting.

I’ve never torn into a 4cyl Honda (I’m an air cooled VW guy). Are cylinders available, or do you have to bore/sleeve to restore. I’m not sure how many miles this has on it.

Again thanks for the reply.

Steve

Hi Westfalia,
I have a few 750's, the oldest is a 73.
Being exposed to the elements can be real bad for a motorcycle. All rubber parts are probably shot. Rust is the culprit that freezes pistons, swingarms, cables, gauges, ruins wheels etc...
Four into one is my go to for maintenance parts for mine and they're out of California so at least you have that.
Try turning the motor over with the kick starter to see if the motor is frozen. That will determine the level of work ahead of you.
The 1970 model is only one year from the first sandcast model and that makes it more valuable. I had a chance to buy a '69 years ago and didn't and I'm still kicking myself.
I did just acquire four 750's and a 450 from a relative so I've been wrenching more than I have in years. Retirement is good.
Good luck in your journey!

 

[Ducklife]

I know there are places sells sleeves and pistons kits, like Dynoman or Cyclexchange. Don't know about anyone that makes new cylinder.

 

[dirtdigger]

Easiest thing to do IF it needs bored is to go to a 836cc piston kit. There are companies that make new sleeves but its cheaper and easier to find a cylinder in better shape. Honda did offer oversizes but they are getting harder to find. I would suggest looking at cyclex and dynoman sites....will give you a good idea of what is available as far as the engine goes.

 

[BAHNST]

Can't give u a lot of technical input for the Sohc...
But i reckon ur dad will be proud with either a resto...or attempted "rebirth" of the bike....
Good luck..

 

[Biker Bob]

I am now the owner of my dad’s old ‘71 CB750 four. This bike is all there but VERY rough and not a runner. It has sat outside under various states of cover for about 30 years minus it painted bits which were thankfully stored inside. Currently its under cover and secure.

Eventually I’ll give it a proper resto maybe once retirement happens…lol. 5-10 years…maybe. So to my question:

What should I be searching/collecting for now that might not be there in the future?

I’ve not done a detailed “needs” list so i can’t really say what will need replacing, but figure rubber/lines/controls will all need replacing. I do have the OG exhaust and guards but they have a few holes. Are some things on the bike “unibtainium”? I come from the vintage VW world and as values have come up a huge amount of reproductions parts are now available compared to even 10 years ago. Is the bike world similar?

Pic is of my dad on it in the 70’s when he used it as a daily commuter. Miss ya pops.

Thanks for any help!

The engine is probably frozen up. Try removing the spark plugs and putting in a couple of eyedropper fulls of Marvel Mystery Oil into each cylinder. Let it sit a day or so, then remove the points cover. Use a 6 point Metric socket and rachet to GENTLY try to move the pistons up and down. Don't force it. If they don't move, stop. Put in a little more oil, wait a day, and try again. Repeat until the engine turns freely by hand. Be patient. This process has worked for me on motorcycle and car engines.

 

[Biebs]

Windjammer fairing and bags are garbage.

 

[Old_Crow]

Windjammer fairing and bags are garbage.

I don't know about the bags, as I never had any of them, but I loved my Windjammer III fairing. Had it on 2 different 750's, and then, when I got into Harley's I ended up with an '82 Tour glide that had a factory frame mounted fairing that was originally designed by Craig Vetter.

 

[dirtdigger]

Do not try to turn over a sohc motor with the point side. It only holds the point advancer and is only kept from turning on the crank by one little dowl pin. The big nut you see is only held on by a 6mm stud that is very easy to bend and break. It is only meant to hold on the advancer and only to be used to turn the motor over during a tune up. It is also advised to only do with the plugs out. These studs are bent all the time by people thinking you can torque on that big nut but its only to be used during tuneups. If this stud gets bent it causes erratic timing and point irregularities. If you really need to turn the motor over to break it loose pull the alternator cover and use the bolt on the end. It is much larger and can take much more torque.

Windjammers were nice for touring and very popular in the day. Dad had one on his 750 and ran it for many many years.

 

[Biker Bob]

You are correct. I gave some bad advice. Your way is much better. Or maybe move the kick starter by hand. With the spark plugs removed from the engine.