08 XP acts like one cylinder shuts down??

[idaspud]

A buddy from Washington with a new 08 XP has a problem with it acting like a fouled plug or one cylinder shuting down when it is running about 6k to 6.5k rpm. It cycles in and out. I rode it and it runs very strong except under this light load at mid rpm. We changed the plugs and they looked great. Any ideas, please. Spud

 

[Ace Freely]

Carb heaters on??

....Who is his dealer??


Ace

 

[idaspud]

Don't know his dealer, will ask

Will check the carb heat too, any other thoughts? Thanks.

 

[MT_mtn_climber]

Will check the carb heat too, any other thoughts? Thanks.

Has he messed with the jets, needles? might be a lean condition. Even the 08R motors are pretty lean in the midrange.....

 

[idaspud]

yes, I think he has rejetted

I again will ask but I think he has rejetted and that was my first feeling when I rode it, it felt like the jets were plugged maybe? Is there jets for the midrange? Thanks for the hints, anymore???

 

[MT_mtn_climber]

I again will ask but I think he has rejetted and that was my first feeling when I rode it, it felt like the jets were plugged maybe? Is there jets for the midrange? Thanks for the hints, anymore???

Tell him to put the stock jets back in it and see what happens. Also if he wants to mess with the needles, get a set for a 04-07 with the adjustable clip and nylon spacer. They work a little better. Midrange is a combo of main jet and needle but mostly needle. Pilots control the bottom rpms, suppose he could have put too small of pilots as well.

 

[EndlessWinter]

A few sets of carbs were sent out with the needle jet (not to be confused with the jet needle) set at different height than they were supposed to.
Basically, if you pull the carbs, lift the slides up and inspect from the back side. You can visually see the height difference between the two needle jets. ( in laymans terms. The brass tubes that your needle drops into)

Unfortunately, this is an irrepairable issue and the carbs need to be replaced.

We have seen it on 2 sleds and the symptoms are dropping a cylinder between 5500 and 6500 rpm. (sounds familiar dosent it)

And by the way. Carbs are on back-order. Good Luck!

P.S. I reserve my right to change my descriptions of a jet needle and needle jet at any time. I seem to always call them by the wrong name. But I think I explained it clearly enough to verify the problem.

 

[MT_mtn_climber]

A few sets of carbs were sent out with the needle jet (not to be confused with the jet needle) set at different height than they were supposed to.
Basically, if you pull the carbs, lift the slides up and inspect from the back side. You can visually see the height difference between the two needle jets. ( in laymans terms. The brass tubes that your needle drops into)

Unfortunately, this is an irrepairable issue and the carbs need to be replaced.

We have seen it on 2 sleds and the symptoms are dropping a cylinder between 5500 and 6500 rpm. (sounds familiar dosent it)

And by the way. Carbs are on back-order. Good Luck!

P.S. I reserve my right to change my descriptions of a jet needle and needle jet at any time. I seem to always call them by the wrong name. But I think I explained it clearly enough to verify the problem.

Good info Endless, have to keep that one in the memory banks....

 

[Kilgorekid]

I would bet that the hand warmers have shorted out you can pull that cover off of the middle of the bars and unplug the hand warmers to see. my sled did the same thing

 

[scoop]

xp cutting out

One of my riding buddies tipped his sled over to change gearing and while on its side oil ran into the fuses and one wiggled out part way. the fuses were on the side I think. It was running bad and while we were trying to figure it out we found that loose fuse, pluged it back in and away we went. I dont know anything about the xp's and dont know what those fuses goto but it worked that time.

 

[idaspud]

Endless

Hey, that sound familiar and I will pass the infor on to the guys from Washington. Appreciate the infor. Spud.

 

[summitboy]

I have talked to a mountain dealer and he had a couple of sleds come back and the DPM rail solenoids were fugged. He said the sleds were running on one cyl. Just a thought.

 

[NoSecondChances]

A few sets of carbs were sent out with the needle jet (not to be confused with the jet needle) set at different height than they were supposed to.
Unfortunately, this is an irrepairable issue and the carbs need to be replaced.
P.S. I reserve my right to change my descriptions of a jet needle and needle jet at any time. I seem to always call them by the wrong name. But I think I explained it clearly enough to verify the problem.

LOL good info EW. I'm curious as always though: How is this irrepairable? Could the carbs not be machined to allow the needle jets to drop down farther? Basically there is a lip on the emulsion tube (the other name for the needle jet - Yes you are using them correctly FYI) that holds it up from falling into the float bowl and the main jet screws into the bottom. Any capable machine shop should be able to machine the inside diameter (ID) of carb where the needle jet drops in, to the OD of the actual needle jet? No? Therefore allowing the emulsion tube to drop all the way down. In theory, it should just be a drilled/milled out or mill the emulsion tube to match if it is a problem with the slot on the emulsion tube or the key on the carb. I'm sure this wouldn't be a factory authorized, warranty approved fix for the issue though.

I'm just thinking out loud since the new carbs are on back order and the simple consequence of this could be someone's motor burning down in the midrange. An elevated needle jet/emulsion tube would be the same as dropping the jet needle down a few clip positions (raising the clip/dropping the needle farther down) which could mean liquid pistons.

 

[EndlessWinter]

You are correct in the assumption that it can be fixed. But from a dealers standpoint for warranty reasons. Carb replacement is called for.
Back in 2002 dealers had to change the heights on the summit 800's. They sent out a special tool to accomplish this. But times have changed and its not quite so easy now.

 

[idaspud]

Endless

He replaced the carbs and it runs like a top now. Thanks for the hint.

 

[EndlessWinter]

Glad to help