SOHC.co.uk Forums > CB500/550

5th gear jumping

<< < (3/5) > >>

Johnny4428:
I have just gone through sorting a fifth gear issue on my 750. I had poor insertion of gear 2/3 into 5th which resulted in 5th gear being disengaged when power was applied. Turned out to be a combination of wear and for some reason about 2mm plus lateral movement with 5th gear cog. After replacing worn gears and middle selector fork plus an extra shim I now have 0.4mm of tolerance. In return I now have almost 4mm of gear insertion. It’s gone to take a few runs before I have the confidence that it’s going to stay in gear though. Check selector mech, make sure you are getting full movement when selecting 5th. Most annoying! Good luck with sorting.

McCabe-Thiele (Ted):
That must be a nightmare to have the same fault again. I'm not familiar with the 500 gearbox but could it be the selection system that sits at the end of the shaft behind the clutch - on the 400 it looks like a system of levers, springs etc?

Nurse Julie:

--- Quote from: Steris on May 23, 2022, 02:42:40 PM ---Well 1500 miles after fitting a new/second hand 5th/4th selector folk the bike is jumping out of 5th again. Surely it cant have worn another one out? So engine will have to come out again this week and see what's happened  :-[

--- End quote ---
What a pain. Let us know what you find.

Oddjob:

--- Quote from: murdock on May 14, 2021, 07:51:08 PM ---The other day when I opened my engine I also found the fork a bit bent and a bit worn , thanks to oddjob I bought a new one on ebay for 25 us$ . they sell them in Europe for up to 170 euros , when you open the engine change the rubber plugs.

--- End quote ---

That's a 550 middle fork, the 500 middle fork is not the same.

Rare as hens teeth new.

Did you change any of the gears last time or just the selector fork.?

I'll be selling a NOS L/H selector for and a NOS middle selector fork soon. I bought a complete set of custom made ones from Italy last month so I'll be using them on the rebuild.

Steris:
The one I fitted last time was from a cb350 twin,  the selector is the same with same part number.  I'll know more once I get the engine on the bench.

Navigation

[0] Message Index

[#] Next page

[*] Previous page