Author Topic: 74 CB750 Portland OR  (Read 1052 times)

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Offline Charlie-D

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74 CB750 Portland OR
« on: October 19, 2015, 10:57:39 AM »
Hi,
My father in law just gave me his old drag bike which is a 1974 CB750 (built). He use to drag it in the mid 90's but crashed on the track, so after his hospital stay he re built it and it stayed in the garage.

I ride a 2009 Harley heritage so these older bikes are a new thing for me and I'm hoping to get some help to get it road safe. He's ran it in the garage thru the years so it runs well and is jetted fine. I know that the gears get stuck/fused together if it sits awhile, we broke them free, through they do tend to stick after sitting for a week or so.

My main concern is braking. It don't have a front brake on it now though he does have the original hardware. I'm wondering if there is a modern aftermarket setup that works better and where I would order those.

Brake lines, the stock ones I want to change out. They just seem kind of weak and I would like to put on some braided. Am I going to have to have these custom made or is there a vendor that has pre made ones?

Rubber throughout. The bikes been sitting for about ten years. He told me about some rubber that helps with the sprocket or something? What should I change out that will most likely be toast.

Aftermarket chrome side plates and securing. He told me that the side plate is notorious for falling off, so I'm wanting to replace it to keep the original. has a vendor came up with something to completely secure the plate so it don't vibrate free?

I'm wanting to keep it as close to as he currently has it style wise as possible. I just want to get it back on the road, made a promise that I would.

on top of all that I'm wondering if all of this is simple enough to do in the garage. I have no problem taking it to a shop and will probably do so just to get everything checked out. But I would like to bust MY knuckles on it if it's straight forward.


Thanks for the time and sorry for dropping all the questions here. I'm trying to fast track this project so I can ride it to his place ASAP.




Offline WV_750

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Re: 74 CB750 Portland OR
« Reply #1 on: October 19, 2015, 10:29:42 PM »
Welcome. Very nice looking bike. I don't have many answers, but I'll take a shot at a couple. The gears sticking might just be bad oil. It needs changed asap if it's been sitting that long anyways. For the front brake, I'd just put the stock caliper on for now as it looks like you have all the mounting hardware, master cylinder and lines still in place. I've seen instructions on converting to a dual disc system if you're up to the task. Is the master cylinder dry? If so, you might have to rebuild it and replace the lines. Pre made braided should be available. Definitely try doing it yourself if you have interest. I just got started work on my first CB (and first motorcycle) and its been a lot of fun. Best of luck!
73 CB750 K3
76 CT90
78 CT90
07 CB900F (919 Hornet)

Offline brandEn

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Re: 74 CB750 Portland OR
« Reply #2 on: October 20, 2015, 05:35:38 AM »
Welcome to the forum. Get stainless barake lines from slingshot cycles, he is a member here. I would just use the stock caliper but get another setup and install it on the other side for dual calipers. Its an easy mod just search the forum for info. As for rubber bits he is probably talking about the cam chain tensioner and the primary chain tensioner. Both of those have rubber wheels that can deteriorate over time. If you drop the oil pan you can see the primary chain rollers for inspection. To replace the engine needs to be torn down. The chrome "side plates" not sure about that. Just make sure your screws are tight. I can't think of any chronic issues with the covers falling off.
« Last Edit: October 20, 2015, 05:38:10 AM by brandEn »

Offline calj737

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Re: 74 CB750 Portland OR
« Reply #3 on: October 20, 2015, 05:45:59 AM »
Oil and worn plates are causing the clutch plates to stick, not the gears.

Fresh side cover grommets help keep the side panels in place.

The "worn rubbers for the sprocket" are probably the cush drive rubbers in the rear wheel, sprocket side. These take up the shock from driveline torque. Remove the rear wheel, remove the left side (sprocket and carrier) and inspect them.

Definitely ring out to www.slingshot-cycles.com and use code SOHC4 at checkout to receive a discount. Provide make, model, year and bar style for your new ready to bolt on braided stainless lines.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Charlie-D

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Re: 74 CB750 Portland OR
« Reply #4 on: October 20, 2015, 10:37:42 AM »
Thanks for the replies! Looks like that covers my questions, appreciate it.

Offline brandEn

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Re: 74 CB750 Portland OR
« Reply #5 on: October 20, 2015, 11:18:21 AM »
HAHA yup cal is probably right about the cush drive, I didn't even think of that.

Offline 754

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Re: 74 CB750 Portland OR
« Reply #6 on: October 20, 2015, 01:48:25 PM »
Nice...did he happen to say how big the motor is...? 836?  900?  1000?
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Charlie-D

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Re: 74 CB750 Portland OR
« Reply #7 on: October 25, 2015, 06:02:06 AM »
Nice...did he happen to say how big the motor is...? 836?  900?  1000?

Sorry for the late reply, wanted to get in touch with him and get all the info right...

(this is a copy and paste)

it's the original bore, which is actually 736cc . guess they though it was close enough to call it a 750 lol.
the pistons & rods have all been matched as far as weight , so they are balanced. the rods have been magnafluxed & shot peened
the head as been ported
the trans has had the shift "dogs" undercut so they stay locked into each gear


Offline 754

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Re: 74 CB750 Portland OR
« Reply #8 on: October 30, 2015, 06:13:39 PM »
Stock pistons are 736 cc.
Your undercut gears may affect shifting.... I would wait for others to chime in on that , or bring it up in High performance section.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way