How much damage did i do?!?!?!? : Kawasaki ZX Forums: Kawasaki Ninja Forum

BradOfAllTrades · 07-01-2009, 10:08 PM

OK so here is the story:

a few days ago i was cruising around 60mph with my buddy and i popped it into neutral to ride with no hands for a second as i adjusted my helmet strap i pulled in the clutch and attempted to shift up to second still around 50-55...well the gears did not sound happy to perform that action it was a godawful noise of metal to metal contact in the gearbox...i still shutter thinking about it

Anyway, i have been practicing cluch ups and i have probably done about 30 or so all but 2 were successful(give or take) then yesterday i did one as i always do WOT in first till i hit the power band flick the clutch and NOTHING happened i looked down and my gearbox had shifted itself into neutral are these 2 phenomenon related and any gueses at how much damage i did with the first one?

Shifty1 · 07-01-2009, 11:09 PM

Couldn't tell you if you did any damage without hearing, looking at or taking apart your bike. But, I can tell you that I have done that before (the shifting from neutral to second while moving/loud clunk thing). And you can avoid that in the future by revving the enigine to match your rpm to speed.

KawaJAG · 07-01-2009, 11:44 PM

Here's a thought. You put the bike in neutral and the output shaft kept turning because it's locked to the rear wheel basically. When you put the bike in neutral (which basically means disconnecting the input shaft from the output shaft) and let go of the clutch (locking the input shaft of the transmission to the... lets just say crankshaft, ignoring the fact that there's a primary reduction gear in there) the input shaft slowed down to match the idle speed of the engine. Now your input and output shafts are turning at pretty different speeds, then you pull in the clutch lever and shift into second, and in an instant the input shaft has to speed up to match the speed of the output shaft... hence the grinding and noise as the dog teeth slammed against each other.

In order for revving the engine (rev matching) to work, you'd need to rev it back to about the RPM you'd be turning at 50mph in 2nd gear BEFORE pulling in the clutch level to bring the input shaft speed closer to the speed of the output shaft... THEN pull the clutch in, put it in gear and let the clutch out.

In a car this wouldn't be a problem because they use syncronizers to bring the two shafts to the same speed gradually before fully mechanically engaging... motorcycle transmissions don't because they're sequential transmissions so getting the input and output shafts turning at drastically different speeds is very uncommon. (though you certainly found a way to do it, hehe)

BradOfAllTrades · 07-02-2009, 12:09 AM

so i shouldnt worry too much about it???? when it happened i thought i tore apart every moving piece in my tranny lol and would that grinding of the dog teeth even that one time have caused the second thing....my bike to jump from 1st to neutral by flicking the clutch for a clutch up? or is it more probable that it just wasnt fully in gear or maybe i tapped it without knowing???

KawaJAG · 07-02-2009, 12:18 AM

Quote:

Originally Posted by BradOfAllTrades

so i shouldnt worry too much about it???? when it happened i thought i tore apart every moving piece in my tranny lol and would that grinding of the dog teeth even that one time have caused the second thing....my bike to jump from 1st to neutral by flicking the clutch for a clutch up? or is it more probable that it just wasnt fully in gear or maybe i tapped it without knowing???

I doubt any damage this single incident caused would have caused it to pop out of gear, but it's possible - see my post on page 2 of this thread.

BradOfAllTrades · 07-02-2009, 12:22 AM

BTW thanks guys for the responses and jag for the detail i understand why that happened now

BradOfAllTrades · 07-02-2009, 12:27 AM

my bike only has 3000 miles on it i got it brand new a month and a half ago i hope the dogs and cogs arent bad already

BradOfAllTrades · 07-02-2009, 12:31 AM

what would be involved in fixing them if i did muck them up

???? and how much?

WARRANTY COMPATIBLE?????

KawaJAG · 07-02-2009, 12:58 AM

Quote:

Originally Posted by BradOfAllTrades

what would be involved in fixing them if i did muck them up

???? and how much?

WARRANTY COMPATIBLE?????

I'm pretty sure they'd say you abused the bike and wouldn't cover it under warranty. It would basically require a transmission rebuild to fix hard parts worn severe enough to cause a bike to jump out of gear frequently. I'd give it more time and see if it continues to jump out of gear on you.

TheReaper · 07-02-2009, 02:40 AM

Quote:

Originally Posted by BradOfAllTrades

so i shouldnt worry too much about it???? when it happened i thought i tore apart every moving piece in my tranny lol and would that grinding of the dog teeth even that one time have caused the second thing....my bike to jump from 1st to neutral by flicking the clutch for a clutch up? or is it more probable that it just wasnt fully in gear or maybe i tapped it without knowing???

These bikes are known to not find 2nd gear while upshifting. Mine does it every now and then. It sucks but, such is life.