07 M1000 WOT Issue

[Hotchief]

Probably discussed before but want to get educated suggestions.

Original owner M1000. Only engine mod a D&D can.
2300 miles, AC oil always used, new plugs and DD oil every season.

Never had so much as a hiccup, always ran perfect in 10 seasons.

End of day pulled a climb and motor all of a sudden sounds raspy, different, slight vibration, at WOT.
Starts and runs fine, usual power and manners, snappy, sounds and acts normal until pinned. When pinned the motor sounds unkept and kind of sickly compared to usual WOT crispness. This is only noticeable at 80% - WOT.

Put new plugs in. Compression 120 across the board, pistons look okay from Y-pipe, slight discolored. Checked exhaust for leaks, didn't see anything.
Ran it a second day, another tank of fuel and it is still behaving the same, no change.

What do you guys think is going down?
Does this sound like detonation? Dirty powervalves? Motor about to let go?

Kind of attached to the thing; I bought it new and it's mint, but don't know what to do next.

Thanks SnoWest Bros...

 

[MountainCat1]

Reeds??

 

[type_a_positive]

Might be powervalves, clean and check that wires are within speck. The wires can also go bad, meaning that they do not move freely inside the sleeve. Also check that the powervalve servomotor is turning, I had one that corroded.

 

[MI1M600EFI]

Doesn't detonation set some sort of code, or flash a light or something?

If you're not seeing that, it could be your powervalves aren't opening, and it's making the engine run terrible in the range where they should be open.

If you clean them, or have recently, and things check out OK, you might check the fuel pressure to make sure it's ~44psi or so. If it's starting to fall off, you may see some issues at higher throttle settings, which correspond to higher demand from the fuel pump.

Other things that I'd be checking... Reeds. D&D can coming apart inside. RPMs correct? (Clutching issue?)

Good luck, and please post back if you figure it out!!

 

[Hotchief]

Doesn't detonation set some sort of code, or flash a light or something?

If you're not seeing that, it could be your powervalves aren't opening, and it's making the engine run terrible in the range where they should be open.

If you clean them, or have recently, and things check out OK, you might check the fuel pressure to make sure it's ~44psi or so. If it's starting to fall off, you may see some issues at higher throttle settings, which correspond to higher demand from the fuel pump.

Other things that I'd be checking... Reeds. D&D can coming apart inside. RPMs correct? (Clutching issue?)

Good luck, and please post back if you figure it out!!

RPM is good pinned - the sound it makes at WOT appears as if it's in pain and just not firing correctly/laboring.
I have never touched the powervalves or the reeds - so appreciate all the suggestions so far.

 

[clutch]

Muffler coming apart internally?

 

[Mike from langley]

Check the pipe and can for cracks. The valves are opening if it’s pulling proper rpm. Mine had more compression. As long as it’s even your probably good.

 

[jim]

RPM is good pinned - the sound it makes at WOT appears as if it's in pain and just not firing correctly/laboring.

Sounds like a high rpm misfire based on the vibration comment.
- Check plug wires...they can wear through due to vibration and cause a misfire at peak RPMs.
- Also related to wires, I once had an odd high RPM issue and one of the plug wires had pulled away from the cap enough to still work, just not at high rpm. So make sure plug wires are seated into the cap and the coils. Also make sure no corrosion in there...if moisture made it's way into the connection, it can corrode and stop working as well.
- Might be a bad coil. You can usually check them with an OHM meter or you can remove one cap at a time and see if the problem is the same or worse. If the same with a certain cap removed, you found the bad wire/coil.
- Stator is next...but this doesn't seem like it.
- Check powervalve sync...if one is lagging it may cause one cyl to be off.
- Voltage regulators go on these sleds too...OHM that out and check.
- Injectors may not be keeping up either or you may have a clog? Double check those if nothing above works.

Sounds like the spark is struggling at top RPM, you are hitting rev limiter or it is going into some limp mode.

 

[Hotchief]

Update: Found an issue

Thanks for all the suggestions guys.

Dug into it with a bright flashlight checking wiring and connections.
Saw something didn't look right inside the servo motor.

Pulled the clear cap and discovered one of the powervalve cables had frayed and snapped - so only one powervalve has been operational. I find it amazing the sled has ran as good as it has.

Anyway now to the replacement work, I should probably clean the powervalves as well in the process.

Hopefully this is a pretty straightforward process. Never messed with this but done plenty of my own maintenance including track swaps.

 

[type_a_positive]

Glad you found it.

I used a sharp knife to scrape the gunk off the powervalves, a soft brush and some cleaningfluid will also help. And stick them back in the right way....

 

[0neoldfart]

Doesn't detonation set some sort of code, or flash a light or something?

If you're not seeing that, it could be your powervalves aren't opening, and it's making the engine run terrible in the range where they should be open.

If you clean them, or have recently, and things check out OK, you might check the fuel pressure to make sure it's ~44psi or so. If it's starting to fall off, you may see some issues at higher throttle settings, which correspond to higher demand from the fuel pump.

Other things that I'd be checking... Reeds. D&D can coming apart inside. RPMs correct? (Clutching issue?)

Good luck, and please post back if you figure it out!!

FYI, there is no DET sensor on the 1000, so you will not get a DET code or flash on the gauge. Power valve cables are a common issue (hanging up) with an aftermarket pipe, as the cables are quite close to most