7k rpm stumble

[yukonrider]

I am at wits end with my machine. It just won't run right. I need help. Its an 07 RMK 600, carbed.

It has, new top end, new clutch springs, new carb boots, new plugs, jetting is dialed, slp pipe and can, blah blah, it is perfect. Except:

I can run the machine up to about 7k rpm if I ease into the throttle, but any time Lay into it (to the bar) the machine will just fall on its face and stumble at about 5500 rpm an. It won't clean up no matter how long I stay there. It works great up to about 3/4 throttle, then once Iget much beyond that it starts stumbing (sounds real confused, almost like a cross between running on one cylinder, and hitting a rev limiter)

I've checked everything. I'm going to recheck power valves tonight, but those were fine. Plugs are cardboard brown, a bit rich at idle. Just reset the tps to spec.

I'm at a total loss.

 

[BB454]

Maybe bad temp sending unit. ECU thinks it's overheating and retarding the timing. Inspect for broken wire or bad connection. Borrrow one to try.

 

[yukonrider]

Yes it sounds like the computer is doing something once it gets up to that RPM. Anything else that it could be? I will be looking at it all today.

 

[PaulAnd]

Reeds checked?

 

[yukonrider]

Reeds checked?

I took them out and cleaned them real well, but didn't 'check' them, what exactly would I be checking

 

[PaulAnd]

Chips and cracks

 

[PaulAnd]

Ves, are not sticking? Ves bellows good?

 

[sled_guy]

Does that motor have a DET sensor on it?

So even if you roll in to it easy does it still act up above 7k?

sled_guy

 

[yukonrider]

Temp sensor checks out as far as testing it by the manual goes, 2.45 ohms at 68 degrees.

Unplugged knock sensor, no change.

un-plugged TPS, runs better for a bit, then same old.

Wont run without temp sensor.

Checked bellows and valves, no rips, and move freely.

If I roll into it it will get to about 7400 rpm and start acting up sometimes not at all, but It wont rev up to 8200, it is better than if I just punch it.

It seems to do it more if the sled is hot. after a short break it will run up pretty well, and messing around in the road (on ice basically) I saw 8050 RPM at max throttle with the track just spinning, the sled was not very warmed up (read not hot, had about 10 minutes idle to warm up)

Once it is warm or being ridden I haven't seen those RPM again, and I'm only running 60g weights.


working on getting a temp sensor to try from a buddy, that seems like a good thing to cross off the list.

 

[gcmci]

Possible stator going out when it gets warm

 

[MARV1]

Check the VES puke line, might be plugged up...