Topic: New member, Purchase 1977 cb750k

[mryan318]

Hi everyone i wanted to introdue myself to everyone on the forum. My name is Matt and I live Minnesota and I just purchased a 1977 cb750k about a week ago now. I have bee looking around this forum for about a month and have found alot of great information(great forum guys). I have a question for you guys that I have not been able to find an answer to. The 77-78 cb750 came with a 17 inch rear wheel with 4.5 tire is and the 69-76 came with a 18 inch rear wheel with a 4.0 tire. Are both of the rims the same widest so you can put a 130 rear tire on(as in where the beed of the tire goes)?

[Cuts Crooked]

The 77 & 78 had 17" rear wheels. I'm running a 130 - 90 - 17 on my 78. Works jist fine.

[mryan318]

Can I install a 69-76 cb750 rear 18 inch wheel with a 130/90/18 onto my 1977 cb750?

[Cuts Crooked]

Can I install a 69-76 cb750 rear 18 inch wheel with a 130/90/18 onto my 1977 cb750?

Why? Honda went with a 17" for reason, I think.  There's a lot of room there in my 78, which is pretty much the same as your 77,  so it might be doable. But...?

[madmtnmotors]

I've put 40,000 miles on my 78' CB750K with an 18" rear wheel and have noticed no ill effects. Be sure to use the sprocket hub from your '77 wheel since the earlier sprocket hubs weren't as tall and your chain alignment would suffer. The taller tire will effectively give you a little taller gearing which improves top end but might feel (ever so slightly) a little sluggish "off the line" to get rolling. You could go up a few teeth on the rear sprocket but mine seems happy with the stock tooth count.

[Retro Rocket]

There is a better selection of tyres made for the 17 than the 18 .

Mick

[mryan318]

Thanks for the replies