Topic: NOS CB750A Engine

[BenelliSEI]

Last night I was offered a complete cb750A engine (no carbs). Supposedly ex Honda Canada warranty part, never run, from a dealer inventory. The gentleman that has it wants it gone. Curious;

1. Does anyone desperately need one of these?
2. Is the top end interchangeable with a cb750K. Good source of new parts?
3. Is the camshaft unique to this engine?
4. What else is interchangeable? Crank, rods?

Thanks for your expertise!

[newday777]

I have a friend here that has a 76 A. I'll ask him. Cost?

[redrider1940]

Do you know what your it is?

Not much is going to be interchangeable. The top end is a detuned version of the K so you probably would want to use it even if it could be bolted on. This engine is also a wet sump and not dry like the K. The transmission is of course very different.

[Don R]

 The one I took apart had a 392 head, cylinders and pistons. The cam is smaller and the stock carbs are 26mm, like a kz1000 oddly enough. The trans drive does have a hi-velocity type chain so the crank gear is different. They have a funky parking brake, it might work off the side stand, I'm not sure so it might not affect the engine.
  I still haven't split the cases, I just want to see what's in there. It looks like a torque converter and two clutch packs. Probably where the new dual clutch transmissions originated.

[BenelliSEI]

The one I took apart had a 392 head, cylinders and pistons. The cam is smaller and the stock carbs are 26mm, like a kz1000 oddly enough. The trans drive does have a hi-velocity type chain so the crank gear is different. They have a funky parking brake, it might work off the side stand, I'm not sure so it might not affect the engine.
  I still haven't split the cases, I just want to see what's in there. It looks like a torque converter and two clutch packs. Probably where the new dual clutch transmissions originated.

Don…. From what you’ve seen I could use the head, barrel and pistons on a K motor? This stuff might be like new……

[grcamna2]

The one I took apart had a 392 head, cylinders and pistons. The cam is smaller and the stock carbs are 26mm, like a kz1000 oddly enough. The trans drive does have a hi-velocity type chain so the crank gear is different. They have a funky parking brake, it might work off the side stand, I'm not sure so it might not affect the engine.
  I still haven't split the cases, I just want to see what's in there. It looks like a torque converter and two clutch packs. Probably where the new dual clutch transmissions originated.

Don…. From what you’ve seen I could use the head, barrel and pistons on a K motor? This stuff might be like new……

Do the CB750A pistons interchange with a CB750K,as far as compression and squish shape ?

[Don R]

 Yes, I think mine has a regular 76 top end except the cam. Guys have used the A cams for a mileage/torque motor.

[grcamna2]

Yes, I think mine has a regular 76 top end except the cam. Guys have used the A cams for a mileage/torque motor.

Do you have a running CB750A Don ?

[BenelliSEI]

I’ve decided to pick this up, next week. Will post pictures. No idea what I will do with it! If anyone needs it as a complete unit, let me know. Note that I am 60 miles N.E. Of Toronto, Ontario, Canada. L0A1A0.

[Don R]

Yes, I think mine has a regular 76 top end except the cam. Guys have used the A cams for a mileage/torque motor.

Do you have a running CB750A Don ?

 Nope, I parted one out that was abandoned in a fence row. It had no title and was outdoors for a long while. I still have some of the good parts and the engine. I took off the top end and shoved the engine under the shelf for future parts use. I saved the wheels, forks and swingarm, I laced the rear to an F disc brake hub and put the front on my drag bike frame.

[BenelliSEI]

This one will end up “under a bench” too. Going to have a look to see how clean it is inside first…..

[grcamna2]

This one will end up “under a bench” too. Going to have a look to see how clean it is inside first…..

Do you have a shop cart to move it around ?

[Don R]

 I've been using the harbor freight small furniture carts, they used to cost $7 on sale.

[BenelliSEI]

That’s what it’s on. Bought a pair at a garage sale. Someone tastefully covered them in old carpet too!