Author Topic: K1 cb750 engine build, thumper  (Read 2095 times)

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Offline 750four

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K1 cb750 engine build, thumper
« on: May 01, 2010, 08:31:26 AM »
I'm in the process of building a cb750 bobber and I'm to the point of no return with the motor. The project will begin with the head and move down and back.
Keep in mind I'd like this motor to thump, lobe, idle low, and run smooth on the roadways. Not going to be a racer( it's a hard tail with 3" under forks)

First on the list are:
Cycle x dual carb 34mm Mikunis
Cam: 370/282 or 360/280?? OK on stock bottom end and compression?
Performance valve springs
Heavier cam chain
HD stud kit
Bigger headers (1.75" shorty's?)
And all of the tricks with cam towers, studs, and oil ports

Not fooling with the bottom end this summer, looking to get through til winter and then bore, add new rods, primary chains, and  tranny work.
I believe to have a very good solid motor to work with here. Just by tearing it down It appears to be clean and still within tolerance.
« Last Edit: May 01, 2010, 08:46:12 AM by 750four »

Offline 750four

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Re: K1 cb750 engine build, thumper
« Reply #1 on: May 01, 2010, 08:41:39 AM »
The rest of the build:


Head pics:
R5 cam? All of the lobes look like this...worn out?


Will drilling small holes in cam towers for oil passages here help?


Tool I made from .125 OD tubing, this with a good size clamp with fit perfectly on top of the retainer and allow access to the remove keepers.


Engine covers I've chopped and blasted:
« Last Edit: May 01, 2010, 08:43:58 AM by 750four »

Offline greasy j

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Re: K1 cb750 engine build, thumper
« Reply #2 on: July 03, 2010, 11:56:15 PM »
I just did a search for drilling cam towers and found this post. I have a k1. hondaman say's to do this in his book, but he's talking about the later types where the rocker shafts are bolted in place to not move, so I'm not sure whether or not I should either...

did you end up doing this?