Topic: 750? What year and model?

[Tews19]

A buddy here is having trouble posting pics so I will post.

This is what he wanted me to post.

I have a 73-cb750k that I buggered up with extended forks and handlebars 30yrs ago. Now I want it back to close to where it was before I started messing with it. I have some pic's of a front end that I need identified. Was told this front end was pulled from a 750 but I have serious doubts. If anyone can help me with the year and model of this front end it would help me out. Thanks! "

[754]

Trees look like 73 750
 The forklegs are either500or late 750.. measure accross the bolts holding caliper on. 500 also runs a smaller diameter disc.

[ekpent]

The brake caliper is a later 77-78 model if indeed off a 750.

[MikeKato]

Trees look like 73 750
 The forklegs are either500or late 750.. measure across the bolts holding caliper on. 500 also runs a smaller diameter disc.

Tews19 uploaded the pics for me until I figure out photobucket and can do this stuff myself: Thanks for the interest. The bolts measure 2" center to center on the caliper but is much smaller than the two other calipers i have mounted on a 73-750k & a 76-750k and they are finned. Also my other 750's do not have those 2 little nubs in the center of the top tree.  (looks like those nubs are related to the later instrument panels). I was hoping the piece in the pictures that looks like a reflector,but I think is a front directional, would be a tell tale indicator of what this front end is off of. Not even sure if that directional is a stock piece. 

Thanks again for helping me get to the bottom of where this thing came from!
Mike

[geminimotors]

Everything looks like 75-78 550F. The two 'nubbins' on the top triple are mounting bosses for the ignition switch.

[MikeKato]

The brake caliper is a later 77-78 model if indeed off a 750.

All the 77 and up K models have the smaller calipers on single disk 750's ?  Google Images is leading me on wild goose chases.

[MikeKato]

Everything looks like 75-78 550F. The two 'nubbins' on the top triple are mounting bosses for the ignition switch.

Ok thanks! I'm going for saftey so I guess I'll start looking again for something else. I traded a front wheel for the forks a few weeks ago and the man said if it didn't fit he would trade back. He seemed like a nice enough guy,hope that he keeps his word. I need to stop getting so excited when I find what I want, until I'm sure it really IS what I want.

Thanks for the help guys!
Mike

[Hinomaru]

While you're shopping around ...

Another way to help identify the correct upper tree for your ‘73 750 is to take note of the rectangular shaped casting recess and its location. Most ‘73 750 and up trees will have this feature while a handful of the early ones do not.   

Right side recess is for a 500/550 model.

Left side recess is for a 750.   

This recess was only used on Japanese market bikes for the over speed warning light caution decal placement. No worries, as the Japanese and USA market CB750 model share same upper tree part number.   

CB500/550:



CB750:

[MikeKato]

Hinomaru: That's extreamly interesting, well the tree in question is definately off a 500/550 then with the recess on the right. My 76 has the recess on the left as expected and my 73 (born 7/72) has no recess.

Hinomaru: what are those on your steering stem nuts?

Thanks!
Mike

[Tews19]

Look like a start button

[Hinomaru]

Hinomaru: That's extreamly interesting, well the tree in question is definately off a 500/550 then with the recess on the right. My 76 has the recess on the left as expected and my 73 (born 7/72) has no recess.

Hinomaru: what are those on your steering stem nuts?

Thanks!
Mike

Mike, I wish those were my bikes, but they are not.

Anyhow, that’s the factory stock warning light and a Japanese home market thing. When the bike exceeds a pre-set KPH speed, the red warning light comes on until you slow down again. The 750 KO thru K2 had the light originally located between the tachometer and speedometer. The 750 K3 was not released in Japan and beginning with the 750 K4, the warning light was relocated to the steering stem nut.

750 K0 to K2 style:

[Don R]

The caliper looks like a 750 supersport or like posted 77-78K. 550's probably looked the same.

[754]

   I missed the ign switch mounting nubs, I knew it was not a 77/78 tree for 750 as it had no choke mount boss.

 The 750 late and 550 calipers are same lookswise But the bolt pattern and arm is different, 550 is a bit smaller than the 750 one.
 FWIW, I would have no qualms about running that fork, brake piston is same size as the finned 750 caliper, discs are smaller (ie, lighter..)..worth considering if going to dual disc.

 Late 750 K forks have a few advantages;
 longer fork legs.. a bit stiffer + fork brace is made for them.
 Caliper is a bit bigger than earlier finned ones,
 Fork tubes are hardchrome, so you can run without headlight ears between the triple trees

[seanbarney41]

that top triple looks to be from a '76 550f, those two little bulges are where the indicator dash/keyswitch mount...now that I think about it, late 750k's and f's use that same dash,  500/550 front ends/brakes are largely interchangeable with 750's (k2-k6 at least), 500/550 frontends are shorter than 750, 500/550 brake calipers and rotors are smaller, but it all bolts up...