Topic: CB750F USA 1978 gear box sprocket

[Flat out]

We (son paid I repair) have just bought a CB750F USA import. Renewed chain and sprockets but gearbox sprocket differs from the details in the manual. We have a single centre bolt and replacement from David Silver is the same but manual shows 2 bolts. Has mind been modified. Which is correct and what securing arrangement should the single bolt style have?

I am a newbe to the forum but congrats as it is great.

[70CB750]

Welcome!

The early models used two bolts, yours is 1975 - 1978 I assume since thats when SuperSports were made and it uses single bolt. 

There is a difference in the output shaft on early models, let me dig out some schema for you.

[lucky]

We (son paid I repair) have just bought a CB750F USA import. Renewed chain and sprockets but gearbox sprocket differs from the details in the manual. We have a single centre bolt and replacement from David Silver is the same but manual shows 2 bolts. Has mind been modified. Which is correct and what securing arrangement should the single bolt style have?

I am a newbe to the forum but congrats as it is great.

The 1977 CB750K and 78's had a single bolt in the end of the shaft.
Some years had two bolts and a plate. It does the same job.

[70CB750]

Here is the old model:

http://www.cmsnl.com/honda-cb750-four-k3-usa_model481/partslist/E++21.html#results

see the groove on the shaft?  You need it to install the holding washer.

Newer model:

http://www.cmsnl.com/honda-cb750f-750-super-sport-1978-usa_model7240/partslist/E++16.html#results

[Flat out]

70CB750 you are a life saver. Second schematic is exactly what we have. So much appreciate your support

[70CB750]

My pleasure  - just tools of the trade.

Here you can find your model:

http://www.cmsnl.com/honda-cb750four_model14344/

if you ever need more schematics.