Topic: Advise please - what to do with half of 750F?

[70CB750]

I scored today. Originally I went for the engine only since the price was right but the guy had the whole front wheel/fork/tripple tree/discs/brakes/fender and rear wheel with brake, carburetors, air box, coils, cables, most of the harness.

The engine itself is clean and turns over easily - hand on kickstart lever - will do
compression test to confirm. Took off oil filter and pan, nothing in it bu remnants of oil that feels good between fingers. Spark plugs are grayish black - good  color.

I was looking for engine for a while since I have a K3 frame in the barn and I was thinking about piecing together a machine in the next year or so.

Now I have more than I expected and all those pieces are in great shape. The question is - is it worth the trouble to adapt F wheels to K3 frame? I suppose the engine will fit in the frame but I was wrong before.

My goal is a reliable and comfortable travelling bike for two - maybe with a sidecar in the future.

Oh the guy was selling all the parts and keeping the frame to build electrical motorcycle

[JohnG]

One detailed way to check things is to get onto a website like BikeBandit and
compare actual part #s.  That removes alot of mystery.

IF it is a 75 or 76  F  then the front wheel will be the same as your K.

The rear wheel is quite different as the F wheel is designed for a disk brake and the K had a drum.

The engine should be identical.  What changes there are , are internal.  The manner in which the exhaust attaches is different but no big deal unless you wish to use an original 4-4.

[splitt]

What year F is it? A 75F or 76F will drop straight in. I have a 76 CB750F in a 75 CB750K frame, straight swap. I'm also using the F wheels and front end. The 77 and 78 CB750F's are like the K models, the output shaft on the engine is offset 3/8" outboard compared to your K3. You can purchase offset sprockets to correct this.

What is the reason to run the F wheels?

BTW, Good score!

[70CB750]

Thank you, guys.  The seller said it was 78 and I will check the serial number eventually.

The wheels are in great shape, tubeless and without spokes. Low maintenance and reliable and the rear disc is a bonus.

[madmtnmotors]

I don't think the 78' Comstars are tubless. My 78 750F has the Comstar rims with tubes. The tire may be a tubeless tire, but I'm pretty sure the SOHC Comstars still require a tube. Good score by the way! Let me know if there's something you don't need!

[70CB750]

You are probably right. I only looked at the tire not at the valve.

The bike must been in pretty good shape as far as I can tell from the pieces I got.