Greetings,
Had my mc28 on the track and it has started to occasionally pop out of gear and then goes back in almost immediately without me doing anything with the clutch or shifter. Always wide open on a straightaway in a higher gear, relatively low rpm, usually around 9-10k so a lot of load on the trans. It's like what would happen if I pulled the clutch in quickly and immediately let it go. Quite abrupt. Occasionally it will actually pop out of gear completely in a false neutral but I attributed that to not getting a fully positive shift with my foot. Gearbox oil is fresh. Any advice on what it might be and is there enough risk of destroying the gearbox I should quit riding it? Thanks in advance!
- Brian

If it's a dry clutch, check for a worn out basket, bended steel plates etc

Also, ensure that there is enough freeplay on clutch cable and that it moves freely.
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2t-racelab.com

I've found NSR's (all the ones I've had on track) occasionally jumpout of gear if you clutchless upshift, especially if you're not really positive on the shift.

The jumping out of then quickly back into gear thing sounds a little like something the CBR400 and RVF400 are both prone to (but not in a high gear, normally in 2nd), those in the know attribute it to worn dog teeth, it's a common fault, especially with CBR's. It feels almost like the chain jumps a tooth. Never heard of it on the NSRs though.
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

It is a dry clutch so I'll inspect that thanks.

fontyyy, that exactly what it feels like, that the chain jumps. My rvf400 racebike will do the same occasionally too. Maybe its just me being sloppy with my foot . . . More likely worn dogs as it has been doing it consistently more often. I don't usually use the clutch for upshifts, maybe I try using it and see if it helps. Thanks for the advice!

99% sure that the engagement dogs on the gears are buggered. I have a big box of gears with buggered dogs if you want them!

Other issues that cause this are bent shifter forks, which even if straight now will get bent if you continue to use it.

I did three gearboxes in the '96 season (SP rules), whereas in '95 (SS rules) I used an F3 box and has absolutely no problems whatsoever. It cost me a place at Shah Alam on the run to the finish line as it started jumping and I got beaten by a wheel.......Damn those cheesy gears!

If you have the enthusiasm you need to pull out the gearbox and take a look at the dogs. You'll probably see rounding of the edges, and if so they need changing. You don't need to drop the engine to pull out the transmission cassette and it's quite straight forward.

Changing the gear selector cog and spring to that from an MC21 gives more positive engagement, and if you round off the corners of the neutral part of the cog then it'll never go into neutral by accident between first and second......then again, it'll be frustrating to get it into neutral at all! But hey, if it's a track bike then just kill the engine.