Topic: 1973 cb500 4-speed

[Bubba0374]

I was just curious; how many of you 500 owners out there have a 4-speed bike? I bought mine like that from the original owner a few years ago and loved it but all the specs and research ive done say they came stock with 5 gears. This also means I have to run the RPMs pretty high to reach higher speeds (55 MPH is @ 5500 RPMs in 4th Gear) to me this jus doesnt seem right compared to the regular specs of the bike. It just feels like it needs one more.

I am planning on a full rebuild soon as im finally done with my nova and this is the next priority. So at that time couldnt i jus swap out the tranny for one that i know worked well and was a 5 speed?

[KingCustomCycles.com]

"swap out the tranny" Well, it is part of the entire bottom of the engine and crankcase?  How about getting a complete different engine for $125 and swapping it in.  That is, by the way, what the gaskets and misc. parts will cost to change your gearing. 

[bryanj]

They never made one

[Bubba0374]

well to be honest if it were just the gearing i probly would jus swap for a diff block, but since I am hell bent on a completely rebuilt 500 engine anyway(bored out, port & polish, new cam, etc ) I figure I might as well get the bottom as fresh as the top while I have it open.

and while i dnt care if the engine is the orig I would like to rebuild it, so should i find one with a 5 speed gear box before I start the  rebuild or try to fix the one i have?

[TwoTired]

To be clear. There is no such thing as a stock CB500 with a 4 speed trans.  They all had 5 speeds.

Yours is broken.  Or, modified by someone.

Depending on what is wrong with yours, you just might need a donor for trans or shifter parts.

Cheers,

[Bubba0374]

well the bike shifts fine and has no other noticeable tranny problems, so what would cause the top gear to jus go away? When I reach 4th gear and upshift again the shifter moves freely and like it should it jus doesnt engage anything. shifter fork maybe?

[SteveD CB500F]

The gearbox in the 500 is well known for being a bit weak. That's why they upgraded it for the 550.

TT is correct - something is broken in there stopping you from selecting 5th gear.

Mine jumps out of 3rd. I suspect a worn shifter fork - yours may be bent rather than worn if you can't get 5th at all.

[TwoTired]

Part of the gear selector mechanism is behind the clutch drum and accessible with engine still in frame.  I'd examine that closely for an assembly error or something else amiss.
This is where the pedal actuates the shift drum and shift forks inside the engine case.
Going deeper means splitting the engine case.

Cheers,