Bike Dies when braking

[Lightndattic]

All- My FZ has developed an annoying and potentially dangerous problem. When braking at anything less than the tiniest amount, my engine will die on me.

The details-
It's started doing this is the last month or so.
It does it using either the front or rear brakes. If I have to grab brake quickly at any speed, it dies.
It idles between 700 and 800 RPM (normal idle).
It does not matter what the fuel level (I first thought it was fuel starvation when the gas sloshes forward).
It's done it when the engine is below operating temps all the way to 225 degrees F (the highest I've ever seen it).
I thought it could be the clutch not fully disengaging the engine and transmission, so I tightened up the clutch cable a little using the lever adjustment, but that hasn't helped.
I've tried different grades of fuel with no difference. I usually run 87 octane ((R=N)/2 method), but switched to 93 octane with the high temps and traffic we've been getting in DFW lately.


The first time it did this, I was about to turn left across a street with traffic coming after exiting a highway (I hadn't noticed it had died). I leaned in and went to feed throttle and let off the clutch and was almost dumped off in the middle of the intersection.


Any Ideas?

 

[dad24hungrykids]

remember the brake lights come on with either front or rear brake application..that is all I can come up with. a short somplace or a major load on the elec. system. have you installed any new lights or anything recently?

 

[Lightndattic]

remember the brake lights come on with either front or rear brake application..that is all I can come up with. a short somplace or a major load on the elec. system. have you installed any new lights or anything recently?

I didn't change the brake light, but I did change to LEDs front and rear for the turn signals and plate light 6 months ago with weatherproof connections and heat shrink. They pull less power than the previous lights, but I'll pull the side pod cover and check those connections and the brake light wire and make sure they're not chafed and shorting.

 

[06FZ6_IN]

Vaccuum leak?

Per 04-06 Service manual idle should be between 1250-1350rpm. I'm pretty sure an 07 would be around the same.

 

[Lightndattic]

Vaccuum leak?

Per 04-06 Service manual idle should be between 1250-1350rpm. I'm pretty sure an 07 would be around the same.

That may be it then. I'm not sure where I got that 700-800rpm is normal idle. I just found the TPS sticky, so I'll check that as well since stalling and irregular idle it a symptom of that.

Thanks for the help!

 

[JAZZ-n-FZ6]

That started happening to me a couple years back and it was because my idle was too low. Once I adjusted my idle to 1250-1350 it fixed the problem. There is a screw on the side of the bike just under the frame.

 

[chaskell27]

I'd recommend pulling the clutch in when you brake. You'll kill the bike every time you brake to a stop without the clutch :ban:

On a serious note. Does it do it more when you have a higher rpm before braking? I am wondering if the inertia of the motor is forcing a stall when coming down from the higher rpm's. If this is the case you may need to adjust the idle so that it doesn't allow the revs to get low enough to be on the borderline of stalling when coming off higher revs.

 

[Motogiro]

If you confirm that it's not an idle problem, (700-800 RPM is way low) you might check your tilt sensor. Check all connections from battery to connector plugs.

 

[Lightndattic]

I'd recommend pulling the clutch in when you brake. You'll kill the bike every time you brake to a stop without the clutch :ban:

On a serious note. Does it do it more when you have a higher rpm before braking? I am wondering if the inertia of the motor is forcing a stall when coming down from the higher rpm's. If this is the case you may need to adjust the idle so that it doesn't allow the revs to get low enough to be on the borderline of stalling when coming off higher revs.

Clutch then brake? Carp, I've been doing it wrong the whole time!

Most of the time when it would die, I would be coming off the highway to a stoplight. I'd gently brake at first, then progressively more until almost stopped then let off to come to a smooth. Nothing even close to a stoppy or even enough to skid the back tire. The whole time I would be braking, the clutch was pulled, so I would be at idle (Yes, I know I should be downshifting, blipping throttle, etc, but I don't usually do that).

I'll adjust the idle and see what that does. Thanks.

 

[Lightndattic]

If you confirm that it's not an idle problem, (700-800 RPM is way low) you might check your tilt sensor. Check all connections from battery to connector plugs.

This will be plan B if the idle adjustment doesn't work. The bike has been upside down once that I know of (Don't ask).

 

[tomari]

crank your idle up to 1250~1350. 700 rpm can damage your engine if not just die

 

[TownsendsFJR1300]

+1 for raising the idle. 700 RPM's are way too low....

I keep my 07 at 1000 RPM's and it doesn't die while slowing/stopping....

 

[oldfast007]

Nope, all of the above are Wrong!! You need a Gremlin Bell :BLAA: j/k

I going with low idle as well, be interesting to see what it really was...

 

[BusyWeb]

Ha ha ha,
if all above does not work, then try to replace your engine oil with good brand !!!
Good luck to be fixed, and let us know what real problem was !!!

 

[Lightndattic]

I bumped the idle up last night and rode into work this morning (10 miles). No issues at all. If the trip home is as carefree, I'd say this fixed my problem.

One puzzling thing I noticed- I had to turn the idle adjustment screw almost all the way to the stop to get it to idle above 1000. I'd say it's only at 1100 with the screw all the way in. I would think there would be more adjustment range than that.

 

[TownsendsFJR1300]

I bumped the idle up last night and rode into work this morning (10 miles). No issues at all. If the trip home is as carefree, I'd say this fixed my problem.

One puzzling thing I noticed- I had to turn the idle adjustment screw almost all the way to the stop to get it to idle above 1000. I'd say it's only at 1100 with the screw all the way in. I would think there would be more adjustment range than that.

There should be more adjustment than that. I think I'd be checking the throttle sync/TPS.

When I did a throttle sync, I cranked up the idle to 1300 RPM (per the manual). Once done, I lowered it to 1000, which I prefer.

Somethings not right if the idle stop screw is in all the way and your still at 1100 RPM...

 

[Lightndattic]

There should be more adjustment than that. I think I'd be checking the throttle sync/TPS.

When I did a throttle sync, I cranked up the idle to 1300 RPM (per the manual). Once done, I lowered it to 1000, which I prefer.

Somethings not right if the idle stop screw is in all the way and your still at 1100 RPM...

That's what I was afraid of.

Just for giggles, I also tried to do the TPS check via the diagnostic mode of the instrument cluster as shown in this thread:

http://www.600riders.com/forum/fz6-...ou-experiencing-poor-idle-mileage-stalls.html

Apparently it never went into the diagnostic mode, never showed 'DIAG' on the display and wouldn't let me select different modes. Is there a S2 specific way to do this that's different for the 07 and later models?

 

[TownsendsFJR1300]

That's what I was afraid of.

Just for giggles, I also tried to do the TPS check via the diagnostic mode of the instrument cluster as shown in this thread:

http://www.600riders.com/forum/fz6-...ou-experiencing-poor-idle-mileage-stalls.html

Apparently it never went into the diagnostic mode, never showed 'DIAG' on the display and wouldn't let me select different modes. Is there a S2 specific way to do this that's different for the 07 and later models?

Check this thread:

http://www.600riders.com/forum/fz6-...ou-experiencing-poor-idle-mileage-stalls.html

Once your in the mode, make sure you check ALL the #'s inbetween, that thier not skipping, missing any.

 

[Lightndattic]

Check this thread:

http://www.600riders.com/forum/fz6-...ou-experiencing-poor-idle-mileage-stalls.html

Once your in the mode, make sure you check ALL the #'s inbetween, that thier not skipping, missing any.

Those are the steps I tried and couldn't get past the d1. Select did not advance the menu or anything.

 

[tomari]

i think your throttle sync screws are screwed up....