Topic: Finally rebuilding my CB 750

[Leino]

Got some Racetech gold valves I'm gonna drop in the forks to get rid of some of the annoying features of FZR forks in stock form. They come with four or five sets of little springs nowadays so plenty of options for me to mess things up 

[newday777]

Got some Racetech gold valves I'm gonna drop in the forks to get rid of some of the annoying features of FZR forks in stock form. They come with four or five sets of little springs nowadays so plenty of options for me to mess things up 

Nice. I need to get some for my stock forks to bring them to life.
Did you get the motor back together? Is it still 65mm as you said early on in this build?
I might take my K5 up to where Mike is moving to today to check it out as winter is threatening to show it's ugly face next week and it'll most likely be our last 79°F of the year around here in New England.

[Leino]

Still 65mm and still haven't finished it. I have... can't remember how many bikes of my own and working on other peoples stuff like the five-yamaha-mix engine and some useless crap I couldn't care less about but need to finish plus a dayjob 

[Leino]

Didn't mean to sound rude but feels like I'm still cleaning out the shop from other peoples bikes and engines and I stopped working on any of that stuff years ago 

Yamaha engine was my own idea and I'm happy to go through with it. Last version was worth 40+hp over stock, hoping to get 50+ with this one.

[newday777]

I didn't take it as rude, just that you have a packed plate.
40+ and 50+ hp increases are a good amount of increase.
I'd love to have the $$$ to put into a CB750 motor to get that increase of hp, but alas, I  have to be careful with expenditures.......

[Leino]

I didn't take it as rude, just that you have a packed plate.
40+ and 50+ hp increases are a good amount of increase.
I'd love to have the $$$ to put into a CB750 motor to get that increase of hp, but alas, I  have to be careful with expenditures.......

21% increase in displacement and almost 50% increase in RWHP using stock parts from five different engines 
A fun project and the only issue with the first one was rods, can't rev it as high as we would want to but that's about to change... from 11600 to 12800rpm with the latest modifications, can rev it even more if it likes it, we will have to wait and see.
125 at the wheel was with 11200 limiter and power was still going up rapidly.

[Leino]

Correction, the old version used parts from three different Yamahas and Suzuki cylinder sleeves, new version uses parts from five different Yamaha engines.
Not that this has anything to do with my CB 

[Leino]

Seat done.

[MRieck]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

[newday777]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

I need one Mike!

[PeWe]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

I need one Mike!

A build thread with all details with  photos would be fantastic!
Displacement, head details, cam, carbs etc, etc...
Compression with a cheap tester on top of that

[MRieck]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

I need one Mike!

A build thread with all details with  photos would be fantastic!
Displacement, head details, cam, carbs etc, etc...
Compression with a cheap tester on top of that

F2 head with large ports, TMR-36, 70mm stroker pistons with raised wrist pins, Carrillo's, undercut transmission etc. Those are the parts I have so far. I was buying a fresh Marine 6mm stroker crank from George S but he can't find it.

[MRieck]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

I need one Mike!

A build thread with all details with  photos would be fantastic!
Displacement, head details, cam, carbs etc, etc...
Compression with a cheap tester on top of that

F2 head with large ports, TMR-36, 70mm stroker pistons with raised wrist pins, Carrillo's, undercut transmission etc. Those are the parts I have so far. I was buying a fresh Marine 6mm stroker crank from George S but he can't find it.

Billet block too....how did I forget that one.

[newday777]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

I need one Mike!

A build thread with all details with  photos would be fantastic!
Displacement, head details, cam, carbs etc, etc...
Compression with a cheap tester on top of that

F2 head with large ports, TMR-36, 70mm stroker pistons with raised wrist pins, Carrillo's, undercut transmission etc. Those are the parts I have so far. I was buying a fresh Marine 6mm stroker crank from George S but he can't find it.

Billet block too....how did I forget that one.

👍😎

[PeWe]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

I need one Mike!

A build thread with all details with  photos would be fantastic!
Displacement, head details, cam, carbs etc, etc...
Compression with a cheap tester on top of that

F2 head with large ports, TMR-36, 70mm stroker pistons with raised wrist pins, Carrillo's, undercut transmission etc. Those are the parts I have so far. I was buying a fresh Marine 6mm stroker crank from George S but he can't find it.

Billet block too....how did I forget that one.

Cam?
The nice streetable cam with even power from low too high numbered 125-70 or for a CB750 more extreme one?

My Billet block is parked for the moment. My K6 runs so well so I cannot change it. 125-75 cam idles really well.

I got the pistons for the Billet block gas ported (horisontal), and I'm eager to find out what that will bring except more rlng wear

I have another slow engine build that I have planned 890cc for. Upper case milled for Billet block just for sure.

Billet block make the engine to look very special. It blends together really well with the later heads as K6 and 392 with the same style. I guess F2 will look fantastic too.

[MRieck]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

I need one Mike!

A build thread with all details with  photos would be fantastic!
Displacement, head details, cam, carbs etc, etc...
Compression with a cheap tester on top of that

F2 head with large ports, TMR-36, 70mm stroker pistons with raised wrist pins, Carrillo's, undercut transmission etc. Those are the parts I have so far. I was buying a fresh Marine 6mm stroker crank from George S but he can't find it.

Billet block too....how did I forget that one.

Cam?
The nice streetable cam with even power from low too high numbered 125-70 or for a CB750 more extreme one?

My Billet block is parked for the moment. My K6 runs so well so I cannot change it. 125-75 cam idles really well.

I got the pistons for the Billet block gas ported (horisontal), and I'm eager to find out what that will bring except more rlng wear

I have another slow engine build that I have planned 890cc for. Upper case milled for Billet block just for sure.

Billet block make the engine to look very special. It blends together really well with the later heads as K6 and 392 with the same style. I guess F2 will look fantastic too.

Yes Per 125-70....it is the best all around cam I've found in regard to idle quality, smooth power and good A/F across the board when on the dyno. Lateral (horizontal) gas ports are good.....I wouldn't worry about excessive top ring wear. If anything it really stabilizes right ring in the groove and greatly reduces flutter at high RPM. It really helps XA rings.
 That block does look nice on the engine Per.....I was very specific about extended finning for cooling and the aesthetic appeal. Laverda did it with their engines and I always thought it looked awesome.
 I have a set of F2 cases too. In general everything associated with the F2 is stronger.

[bear]

What are you thinking regards valve's and guides Mike?

[MRieck]

What are you thinking regards valve's and guides Mike?

Iron guides from Yamiya. I move the C clip .080" up the guide so it sits a bit lower in the head for retainer/seal clearance. F2 valves that are out of Europe....stem tips are tougher. I don't know....maybe run lash caps and not have to worry about stem tip wear anyway. I have several sets of Beehive springs too.
 The Yamiya iron guides are really nice pieces.

[PeWe]

CycleX SS 34mm valves for K if not too tall for an F2 head?
(F2 valve stem a little bit shorter.)
4 pcs $48US

[MRieck]

CycleX SS 34mm valves for K if not too tall for an F2 head?
(F2 valve stem a little bit shorter.)
4 pcs $48US

I wouldn't give CycleX 1 cent of my money.

[Leino]

Nice work kiddo. I have 1 more CB engine in me.....it can be almost 115RWHP to the rear with stroker built F2.....probably more..... I have most of the parts.

Thanks Mike! Still have a lot to do but it's finally coming along the way I wanted it in the first place.

[bear]

CycleX SS 34mm valves for K if not too tall for an F2 head?
(F2 valve stem a little bit shorter.)
4 pcs $48US

I wouldn't give CycleX 1 cent of my money.

 

[Leino]

CycleX SS 34mm valves for K if not too tall for an F2 head?
(F2 valve stem a little bit shorter.)
4 pcs $48US

I wouldn't give CycleX 1 cent of my money.

Must be a story behind this I don't know about 

[HondaMan]

Seat done.

I like the stealth engine in this one.

[Leino]

Seat done.

I like the stealth engine in this one.

Yes! Several of my bikes share the same technology