650r second gear jumping out

Hi, any one out there had any problems with second gear that keeps jumpng out when winding the gas on.

Striped the engine down at the weekend, all the teeth are ok. Selecter fork for 2nd gear is is marked and worn slightly. 2nd gear and 5 th gear on the countershaft where they slide into each other is worn. The bike only down 2000 miles. Anyone had a simular problem.

I found these picture on this website. The same has happened to my bike.




Yep, the dogs are worn out. From not shifting using the clutch right. Cost me $$$ and now I have a 680cc bike.


These pictures, are they from your website. Replacing the 2nd gear ,5th gear and the fork did that cure the problem. Or was there some sort of on assembly fault from honda The parts cost $300 in the united kingdom.

thanks Darren

what's the "Right Way" to shift? i never heard of this kind of issue.....


what's the "Right Way" to shift? i never heard of this kind of issue.....


If you're around a number of bikes long enough, you'll likely to see or experience this issue and I've seen it plenty in other peoples bikes, primarily on bikes where clutchless shifting was used. It happens to both two and four strokes, but I believe it's more of an issue with some four strokes due to the typically heavier engine braking, more flywheel effect, etc. If you shift without the clutch, make sure you use proper clutchless shifting, especially on a four stroke. Even if you shift with the clutch, you should still properly time your shifts if you want to maximize the life of the gearbox. The trick to smooth shifting is to get everything spinning at the same speed and time the shifts in relation to the engine speed. Once the internal parts are spinning at approximately the same speed, the engagement dogs will mesh smoother and softer with the gears whether you use the clutch or not. Up shifts are the easiest and you should make the up shifts when you let off the throttle to neutralize the load. Downshifting is the hardest to properly master and more often than not you'll have to blip the throttle to bring up the engine RPM to neutralize the load for a proper downshift. A lazy or soft shift can also be a bad thing, so make your shifts firm, but not super quick and don’t ride the shifter or you’ll be putting excessive pressure on the shift selector and wear out the shift forks prematurely. If you’re not proficient in clutchless shifting, you can quickly damage your gearbox and repairs can get very expensive.

Intermittently popping out of gear can also be caused from a bent or worn shift fork, but more than likely you'll find worn engagement dogs. Once the dogs/fingers/cogs (whatever you want to call them) get rounded off enough (usually near the top), they don’t always fit square and secure in the corresponding slots or holes in the gear and the force inside the transmission pops them apart, hence the transmission popping out of gear. The dogs can be 'undercut', which means they're cut at a slight angle (i.e. picture an upside down isosceles trapezoid) so they're pulled & locked together while under a load as opposed to simply being square with each other, but like most things, there are tradeoffs to consider.

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