2005 800 running on one cyl? goin to cooke soon and need help!

[ragincajun]

went riding yesterday and the sled ran great all day. when we were heading out it all the sudden started to hesitate and wanted to run on one cyl and was popping and back fireing. we stopped and changed out plugs and they looked fine just dirty. put new ones in and no change. the mag side was the one running funny but it was still getting spark. we couldnt tow it out from where we were at so we limped it out under its own power but it would still pull 8k rpm on the road even though it sounded like it was running on one cylinder. when we got to the truck we checked the plugs, pto side was alright, mag side was nasty black and wet. when we got home we fired it up on the trailer and it would hardly run and backfire and pop.

anyone have an idea of wtf is goin on? reeds? ignition problem?

 

[hymark860]

check your crank phase. stick pencils or something in spark plug holes and make sure they move opposite at all times. check reeds also for chips and they lay flat on reed block.

 

[ragincajun]

are you thinking the crank could possibly be broke?

 

[eddy]

Run Q

Check that all DPM hoses are connected and have no fluid in them. Also clean out spark plug caps and put in silicone grase to get rid of all carbon tracks.

 

[sledsrock]

Ring spun on piston. Seen it several times. Do a compression check.

 

[801]

sounds loki the ring spun on the piston!! Have had it happen with the exact same result!

 

[ragincajun]

thanks guys

 

[sniperjms]

Just had very similar symptoms on my buddies 05 Summit 800. Turns out one of the carb boots had cracks and was sucking air in. The first sign that I could see was the rubber was delaminating on one of them. Sounds like this is a common problem with these sleds. Remove the air box, then the carbs, and then remove the carb boots. We had to remove the clutch bolt to slide it out of the way to get the air box out. You'll have to take them off to see the cracks. I had to pull/twist/tug on them a bit once removed to see the cracks better but they were definately toast. I found a massive crack that ran almost the full length on one side. Getting the reed cages out of them was a bugger but they did come out with some persuasive pulling and careful prying. Careful I think the reed cages are plastic. Anyways, had he rode it this way he would have definately cooked his pistons from running lean and hot. If you got one bad carb boot then the other one is not far behind so replace both at the same time.

 

[ragincajun]

did a compression check today...125 on pto....mag side, no compression. what are the chances the ring cought a port and trashed the cyl?

 

[Danzick]

if your luck is anything like mine... 100%

 

[sledsrock]

did a compression check today...125 on pto....mag side, no compression. what are the chances the ring cought a port and trashed the cyl?

I would lay money on it!

 

[ragincajun]

well he pulled the head off...cyl has a nice score in it but i think it can hone out. head is trashed and got a piece of the exhaust valve. can he throw a new top end on it or should we split the bottom end and make sure nothing got down in there?

 

[Waterdawg]

Same thing happened to me. Had to buy a cylinder, and a new piston. I got my cylinder from the seadoo clinic. Don't remember how much it was, but I got it pretty quick.

 

[ragincajun]

did you have to flush the cases? what are the chances of pieces making their way into the bottom end?

 

[bikerjustin]

what are the chances of pieces making their way into the bottom end?

100%

 

[Danzick]

you cant hone very much off these cylinders.... the bore will get to be too big and you'll have piston slap.

 

[Davenjw]

your lucky you don't have a hole in the bottom of your cases. (assuming you don't) it doesn't take much getting caught between the crank and the cases to make a nasty crack/hole.

thank you for reminding why I wanted to do the piston update the second I bought my REV