2010 M8 crapped out

[stuckenough]

Hey Guys (and Gals)
Last run of the year last spring my M8 just out of the blue...started good, then a few Kms up the trail to Chatter stopped reving. I nursed it up to the lodge and on the way up every once in a while the RPM's would come back to normal for 30 seconds or so and then quit.
Just wondering if this has happened to anyone else and how they diagnosed the problem.
I thought maybe a faulty plug or bad fuel...but it seems to run well in one cylinder and not the other. Could reeds be the issue? And if so would it run sporadic for 30 seconds at normal RPMs?
Any advise is mucho appreciated.

btw...HAPPY NEW YEAR

 

[0neoldfart]

Any mods? I've seen poor grounds or injector harness damage under the y-pipe heat shield. Could also have a poor stator or coil. Injector could also be sticking, try swapping them side to side & see if misfire follows the injector.

 

[fj40]

Check the reeds, I had that happen to mine last year.

 

[moyiesledhead]

First thing I always check now that I've seen it happen.....check the wiring plug on your ECU for corrosion. It causes all kinds of weird problems, and it's easy to check before you start looking at all the other stuff. We did it the other way around last year on my nephews sled. Lesson learned the hard way!

 

[stuckenough]

Any mods? I've seen poor grounds or injector harness damage under the y-pipe heat shield. Could also have a poor stator or coil. Injector could also be sticking, try swapping them side to side & see if misfire follows the injector.

Just a can...nothing else.

 

[stuckenough]

Thanks...that's usually my advisers well. Always look at the simplest fix first before you start tearing everthing apart. I'll check that plug first and keep my fingers crossed.
thanks again

First thing I always check now that I've seen it happen.....check the wiring plug on your ECU for corrosion. It causes all kinds of weird problems, and it's easy to check before you start looking at all the other stuff. We did it the other way around last year on my nephews sled. Lesson learned the hard way!

 

[Rjjtcross8]

I have to agree with the electrical mentions, the wiring harness on this sled can easily get pinched up in places

 

[stuckenough]

Check the reeds, I had that happen to mine last year.

Now If it is the reeds...what all has to come off to check them. I'm an old Yammy guy and it would be a twenty minute job to check the reeds and tons of room to do it.
Looks as though things are little tight on the old cat and not a ton of wiggle room. Does the air box come off fairly easy or should I pound a few beers first to calm the nerves.
Life would be a whole lot simpler with a service manual!
Anyway...thanks all you guys for the advise so far.

 

[moyiesledhead]

Now If it is the reeds...what all has to come off to check them. I'm an old Yammy guy and it would be a twenty minute job to check the reeds and tons of room to do it.
Looks as though things are little tight on the old cat and not a ton of wiggle room. Does the air box come off fairly easy or should I pound a few beers first to calm the nerves.
Life would be a whole lot simpler with a service manual!
Anyway...thanks all you guys for the advise so far.

Not 20 minutes on a Cat. The air box is easy....the rubber boot between there and the throttle bodies, not so much! I would run a bore scope in through the throttle bodies and have a look at them before you go to all the trouble of taking it apart. It's been a PITA the 3 times I've done it.

 

[stuckenough]

Not 20 minutes on a Cat. The air box is easy....the rubber boot between there and the throttle bodies, not so much! I would run a bore scope in through the throttle bodies and have a look at them before you go to all the trouble of taking it apart. It's been a PITA the 3 times I've done it.

Thanks for the heads up...I'll have glance at them first. It looked like a cluster to access them...damn!

 

[Uptown]

no no, reeds aren't that bad, if you have a decent place to work on it. remove hood-5min, remove air box-5min, then squish and ram air boot out of the bulkhead-2min, remove heat shield from oil tank. all that's left is the throttle bodies then reed cages. worst part is the small coolant hoses on the throttle bodies. I believe you can leave them attached but you gain more room to get them right out of the way. 2-3hrs. there is gaskets between the reeds, remove gently or pick up new ones before removing. iv only seen reeds chipped, and it still runs wot good. sputters at low rpm.
sounds like another issue, any codes?
power valve cables? had 1 cable frozen. throws codes and \or sputters but runs at wot . if it trowa code it goes into limp mode

 

[stuckenough]

And the winner is.... any ideas what would have caused the reeds to break so badly. Also any chances the pieces would do any damage to the cylinders or would it just burn up?

 

[fj40]

Should be good that's what mine looked like.
I just put new ones in and ran it for over 1000 km no issues.

 

[Rjjtcross8]

The 10's and 11's just had bad petals that were prone to breaking.

 

[mustard73]

Interesting. Was it only the top or only the bottom petals that broke? Or was it one of each?

 

[KatMan]

quick question. what are long term implications of the broken pieces running through your engine?

 

[ippielb]

Check your throttle safety switch its easy. Unplug it see if it runs well.

Throttle position sensor could have a bad connection. And like others said the grounds.

 

[ippielb]

quick question. what are long term implications of the broken pieces running through your engine?

Reeds are softer then everything else in the motor. It may lightly scuff some stuff but it would come out through the exhaust pretty fast if not disintegrate.

 

[stuckenough]

Interesting. Was it only the top or only the bottom petals that broke? Or was it one of each?

Both on top

 

[stuckenough]

One more dumb question...I know I can probably find the answer on the Internet...but does anyone know the torque specs for the reed case bolts and the Y pipe exhaust nuts..oh ya...and the power vale bolts ( thought I better clean those little devils up) while I was all greased up.

thanks