Buddies GSXR750 Quits at 80MPH
 

My buddy just bought a GSXR 750 and on his way home he was on the interstate and got up to 80MPH and the bike just quite on him. but the responded again once it dropped in speed. Whats up with this? has the governor been messed with or what. Any helpful advice would be nice.

id check the kickstand switch maybe?

whats he done to it? Does he have a power commander? If so get rid of the power commander.

Fuck all this. Tell your "buddy" to sign up here and ask the question himself.

What's wrong marko, you don't like trying to fix things from "he said the thingamajig was loose and wiggled around a bit, but thinks the doofrickus might be the actual problem" stories? :lol:

Sounds like a mapping problem to me as well.

JC

It only happens when he gets to 80 MPH?

Could it be the flux capacitor?

:scared:

that was 88...

All new Suz 750 have a type of traction control in the ECU. The ECU uses rpm, gear, and throttle position to determine if it is being ridden by a complete dork and then the ECU cuts fuel and ignition appropriately.

What year gix was this, and what gear or RPM?

I don't see how a power commander would be at fault. Even if the previous owner didn't get it custom mapped, it isn't going to be SO bad that it would cause a complete shutdown at a certain speed.

Sounds like a short somewhere.

Don't need to go over 80 anyway, that's speeding and speeding is DANGEROUS!!!!!!!!!!!!

:leaving:

Seen a few power commanders fail and cause issues. It's easy thing to take out and check to see if it is causing an issue. Simple things is where you should start with electrical issues, things you added or have done that could cause issues.

Correct.

Honestly I would first check fuel line and tank vent line for kinks. What flows at 40 might kink up at higher pressure or consumption rate.

Ya and define "quits"... does it stop making power or shuts off completely? I would suspect add ons as well. Baring that, I'd inquire if add ons were taken off that left loose wires, connectors, injectors, etc. Then I would check to see if the exhaust valve is stuck closed, some idiot may have replaced the exhaust when they owned the bike and then put the stocker back on without hooking up the servo motor. Then I would tell him to shift into 2nd, he's hitting the rev limiter on a bike that has had it's sprockets modified 1 down and four up...:lol:

Huge possibility. So much so that my local HD dealer won't even install PCs anymore.

Still think it's a short, maybe a wire rubbing against the subframe. Either that or bad plug wires, or maybe the regulator/rectifier is bad.

Wow we're alot of help. So far we have covered fuel, fire, and air...Really you have to experience the problem in order to start diagnosing. This 3rd person account lacks details and facts.

almost all of the elements - someone try for Earth :lol:

Garbage in, garbage out...:lol:

JC

No doubt.

Almost all those are very good ideas and i appreciate the help. Ill let him know. The ones i will rule out though are the Exhaust, wiring, removal of add-ons, and power commander. None of those apply cause its got the stock muffler, wiring has already been looked over with a magnifying glass lol, and the power commander... well there isn't one haha. Im going to go over there later today maybe and help him diagnose the problem better. He is a newb to motorcycles. He knows practically nothing about them and just calls one of his friends usually me or my friend Adam and asks us.

I have a theory that there is a problem with the computer itself and its needing to be reset. I have instructed him to disconnect the battery and then try the key in the ignition to drain the remaining power in the system. Then reconnect it and try it out. Thats supposed to fully reset it so hopefully its as simple as that.

Does it lose electical power(do the gauges and lights still work)?

Did he hit the kill switch by accident?

Wouldn't that suck if he did!

Lol i didnt think of asking him that but i doubt it since it happened multiple times on the ride home. But the lights stay on the tach starts to drop as he loses power and the speedo goes to zero but the thing stays on. He tried reseting the computer and got it to 90 but was only able to drive down a road near his house cause he didnt have time to go anywhere else or anyone to follow him so he didnt want to go far. It may be fixed lets hope.

A friend of mine bought an 06 R6 with less than 400 miles on it. Once we got it home it would fall flat at 8k rpm in every gear. Only mod on it was a Yoshi 3/4 pipe(?).

We checked pretty much everything that we could and found out that only the first bank of injectors were working and nothing we tried worked.

He bought a Power Commander...had it dyno tuned and from that point on it ran like a scalded dog. :skep: :screwy:

It made no sense to us or even the guy that tuned it why/how just the slip on pipe would affect this but all I can say is once we added the Power Commander it ran to redline with no issues at all. :scratch: :idk:

Maybe there was an ECU issue and this corrected it but we had already tried the disconnect battery thing a few times with no luck.

You should take it for a short ride to see if it happens for you and so you can get more concrete info of the symptoms.

if the speedo drops to zero when this happens, it's either a sensor or the ecu

what model year is this? what electrical mods does it have?

Ill ask him if he will let me but i would really hate for something really bad to happen while i was on it. I don't really like riding someone else's bike because of that reason.

Its an 05 GSXR 750. It is completely stock to my knowledge I will go over it more throughly when i get over there later this week but i don't believe it had anything done to it.

If all else fails, smash it. Rider style.