Topic: Question about cb750 purchase

[sbaugz]

I'm new to this forum. I usually frequent the honda twins forum as I have owned several but I'm thinking of taking the plunge and getting a cb750.
Thru a friend of a friend, I got in contact with a guy who has a cb750 for sale. All he can tell me is that it's a 1977 "k" model, so I am assuming k7? I asked what exhaust looks like and he says its 4-into-2 (I assume its aftermarket), and the bike has laced wheels, but the rear wheel is not stock- it's 18".

He says he drove it up until a few years ago. While out west, his chain broke and cracked the engine case. He repaired with JB weld and purchased a crankcase from a junkyard but never installed it. He's asking $700, but it's negotiable. Price includes the spare crankcase. He said it leaks a small amount from crack.

I guess my questions are, does that seem high assuming it doesn't run and the crankcase is cracked? What do I look for with regard to the spare crankcase to make sure it fits with the bike? Do I need the entire lower engine block and all internals or can you simply swap a case and use existing internals with new case? I don't want to drop a lot of money into this bike if I don't even know it runs so can I remove jugs without replacing piston rings assuming compression is good?

I am debating not even bothering to look at this bike due to issues with crankcase.

Thanks for help

[goldarrow]

I say skip it

[Shane72]

I'd take a pass on this one too.

In your part of the country, you should be able to find something in a CB750 for under a grand (if you're patient) that doesn't come with quite so many known headaches.

Well, unless you want to have the total rebuilding experience thing, then, go for it.

All the best,

Shane

[sbaugz]

I'd take a pass on this one too.

In your part of the country, you should be able to find something in a CB750 for under a grand (if you're patient) that doesn't come with quite so many known headaches.

Well, unless you want to have the total rebuilding experience thing, then, go for it.

All the best,

Shane

Sound advice there. I think you guys are right. I was thinking he'd drop to $500, but even then it's probably not worth it.

[Stev-o]

First off Welcome!   Yes, a K7 is most likely a 1977 K model, they came with large chains [630], surprised to hear that it broke. This was a common problem with the earlier models that had the smaller chain [530].
You didnt state what your mechanical abilities are or whether you have the tools or shop to do an engine swap, not an easy job.
Are you up for a major job such as that? On the other hand, some guys on here have successfully repaired cracked cases and run them, so that may be an option.
I suggest you go check it out and see first hand what cond the bike is overall.

Good luck...

[MoMo]

I'd take a pass on this one too.

In your part of the country, you should be able to find something in a CB750 for under a grand (if you're patient) that doesn't come with quite so many known headaches.

Well, unless you want to have the total rebuilding experience thing, then, go for it.

All the best,

Shane

Sound advice there. I think you guys are right. I was thinking he'd drop to $500, but even then it's probably not worth it.

definitely not worth 500.    BTW, you cannot replace just the lower case as cases are matched. If you can repair the case externally it may be worth 500. 

[754]

You can weld and repair both cases with topend on motor.. But it takes careful hand work. . If it leaks a bit, now, maybe you can stop it..
 At anyrate, you should look at it with. Sprocket cover off.. Sometimes its a small hole in one case, other times..both cases.