[austinzx6r]

A problem present before my 8K service (uneventful - just filter cleans - all valves OK) and still present afterwords. .

Pull in the clutch while running at say 9K+ RPM and let off the throttle completely. Engine usually stalls. Dropoffs from lower RPMs bring it back to the 1100rpm idle point. No trouble w/ starts/restarts.

What am I (and moto shop dude) missing?

 

[ash]

1100 rpm is a bit low anyway, raise it to 1300 rpm
It could be the carbs out of balance or a pipe off (airleak), It definately sounds like its on the intake side.

Ash

 

[-gary]

Are you jetted for the correct altitude? My SL jetted bike would stall when I let off and wouldn't run under 1k after I brought it to Denver (+5K) ft.

-gary
'02 6R

 

[austinzx6r]

No jetting problems w/ altitude that I can imagine. I haven't changed altitude (low - Austin Tx) since the problem cropped up, give or take a few vertical feet []

Carbs were synched during the 8K service - no diff.

Idle speed is at recommended setting I think - 1100-1200 rpm.

I am starting to wonder about a vacuum issue, sudden/extreme drop in RPM = sudden vacuum change and air/fuel lock.

Any thoughts in this vein?

 

[Cailith]

Vacuum leak is very possibly something to do with it.

Red 2002 ZX-6R 636

It's not the speed that kills, it's the sudden stop...

 

[bladecutter]

Hate to ask this now, but when did the problem actually start to occur originally? What had happened to the bike that the problem started shortly afterwards?

Did you do any work on the bike before the problem happened? Did you fill the tank with gasoline and the problem started happening? Did the bike sit for quite a few months, and you've just put it back on the road and now it isn't working right? Did the bike get knocked over or crashed?

Something caused your problem to happen. I'm actually thinking something along the lines of the carbs not being tight enough to the intake boots, and you have a leak preventing a decent idle.

BC.


I didn't do it, I swear.
And even if I did, what makes you think I would admit it to you?

 

[austinzx6r]

Ah good question. There was a fillup about 30 miles before the first time it stalled, but other than that no "event". Since the stall requires a radical RPM plunge which is not typical (i.e. I usually would be engine braking coming down from high RPM) the problem could have been latent prior to the fillup. No other evidence of gas-related problems; she's smooth running otherwise.

The carb boot suggestion is something I'll look into. Since the idle is just fine normally, I am not so sure about this path.

Thanks for the ideas - keep 'em coming!