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"New" 1971 CB750 K1.

JoeMama

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Greetings All,

Let me first extend my thanks to the moderators and members for making and sustaining this website. I'm not new to motorcycling but I'm new to the site and a new owner of a 1971 CB750 project bike, so it's great to have this resource and its members' experience for help and guidance.

From what I know the bike has been sitting in a garage for some years. The PO had always intended to fix it up but life events got in the way. Through a mutual friend, I heard the owner had decided it was time to find the bike a better home...I promised I'd definitely give it a good home and all the love and care it deserved...so, here I am.

I've been told that once upon a time it had an 816cc big bore kit installed. When starting the bike after the mod, the engine made some noise that caused some concern. It was shut down to be troubleshot when time allowed. And it's been sitting ever since.

The odometer reads 4,434 miles. Not sure how true that is but the date on the title says 1979 at which time it had 502 miles on it.

I haven't had a chance to do anything with it other than cart it home. Hopefully, with some warmer weather this weekend I can wash some of the garage age off of it, see if the motor is free and pinch myself to see if I'm really dreaming!

Looking forward to swapping tall tales and tech experience as time goes along.

Joe Mama (a.k.a Kevin)
 

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Yeah, the pipes look like a pair of homemade 2 into 1s. Either that or they're some other model's stock set or an aftermarket set from who knows where. What makes you say the cylinder block isn't a factory one? Other than being painted it looks the same as others I've seen in photos.
 
The way the fins are positioned mainly. Could have been modified but I don't know. If it has a big bore kit that cyl block must be different or machiened. Could be factory, hard to say.
 
The way the fins are positioned mainly. Could have been modified but I don't know. If it has a big bore kit that cyl block must be different or machiened. Could be factory, hard to say.

I searched on 816 big bore kits after I got the bike home. All the ones I found looked to be cylinder sleeves and pistons. Maybe this one was some funky make that came with a block.

I was planning on pulling the top end to see what could have made the noise that concerned the PO. I'm hoping it's something simple like a piston installed in the wrong direction and that nothing got crunched when it was first fired up since it was shut down right away.

I'm a complete CB750 newbie so hopefully the block will have a part number that I can chase down to see what I've actually got.
 
Looks like a stock block to me. Never heard of 816...either 811 or 836. All that is required is boring the stock block for these kits, no new sleeves needed.
 
Check your vin to title. I don't think you have a 71 K1.
More like a K3 or newer.
Fork ears and instrument cluster are the giveaway.
Great looking project bike for sure. If it is an 836 you got a bonus!
 
Check your vin to title. I don't think you have a 71 K1.
More like a K3 or newer.
Fork ears and instrument cluster are the giveaway.
Great looking project bike for sure. If it is an 836 you got a bonus!

Frame VIN = CB75011182xx

Engine VIN = CB750E11180xx

Title states the same.

Everything I've read tells me that was early in the 1971 build year. It's got the non-vented side covers, black painted front brake caliper and the beam opened throttles meantioned in articles covering model differences. The fork ears and headlight bucket aren't painted so maybe it had a different front end glued to it at one point.
 
Check your vin to title. I don't think you have a 71 K1.
More like a K3 or newer.
Fork ears and instrument cluster are the giveaway.

I'd say 73 or 74, those turn signals are pre 75. But, you never know, al lot can get swapped in and out of these old bikes over the last 40 years.

Have fun with it.
 
This post is 5 years old. Please start a new post with your vin and the information you are looking for.
 
There was no vin in this post for anyone to tell you what your engine is....

Remember, this is all voluntary, people come on and help when they have time. Sometimes you gotta give it a couple days to get answers, people are busy.
 
There was no vin in this post for anyone to tell you what your engine is....

Remember, this is all voluntary, people come on and help when they have time. Sometimes you gotta give it a couple days to get answers, people are busy.



RC01E-2231420
 
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