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Discussion Starter #1
Just got back from some riding. I listend to my pop take off on my XLT SP - at high rpm (not sure where - probably around 7k), or a WOT take off, you can hear a random pop... almost a miss maybe? It's strange. I've never heard it before on anything. There is no loss of power, RPM's don't change or anything. Am I just being overly-cautious and this is normal? Maybe random detonation?

Plugs and wash look good....

Any ideas?

Bryan
 

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is it for sure coming from the exhaust? sometimes on a hard take off, those sleds would skip a cog on the track. check the track tension. also, look at the track cogs and the drivers for wear. i've had a few sleds like that skip on me and if you are a bystander, it does sound like a poping sound.
is it a single pop, or does it keep doing it? elaborate a little please. -Polaris Doc
 

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Discussion Starter #3
I just put new slides on and adjusted the track on Thursday. While I had the skid out I went through it, and checked over the track. It all looked good to me...

When I said it was random, I meant it wasn't to any particular rhythm. Pop pop.....pop...pop...........pop.....pop. Does that make sense lol? I'm no musician, but it wasn't consistent. It wasn't one particular cylinder every revolution. It obviously could be just one cyl, but it's just not every time. When you WFO take off, it's not until the R's get up to around 7k-ish.

Does that help at all?

Bryan
 

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When's the last time you cleaned the carbs? Take the plugs out also and see what they look like. should be a nice tan color on all of them. Could have an air leak somewhere or carb problems. Ya gotta do some digging and find out more info. let me know. -Polaris Doc
 

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Discussion Starter #5
I just went through the carbs, and plugs/wash look good.

You're saying it could be an air leak, which is what I was looking for. I'll go spray it down with carb cleaner and fill you in.

-Bryan
 

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Discussion Starter #6
Well upon further investigation, when I let the sled sit overnight, I pull the plugs and they have the dreaded white/grey goo. Not a lot, but a little. Maybe a high-rpm coolant intrusion causing this? It's in all 3 which I find weird. Head gasket for sure?

Never taken a monoblock apart- is this o-rings or a gasket?

FYI compression is 120 across the board.

Man I'm in trouble. I leave friday morning. Time for some phone calls tonight! Being in Chicago, my parts availability SUCKS. I might have to have the gasket set overnighted to my Aunt's. That would probably be cheaper than trying to find one at a stealership around here.

Bryan
 

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This is a gasket motor. You'll need p/n 3085005. The head cover has one big o-ring to seal around the cylinder, and three little o-rings under the cover where the heads poke out the cover for the plugs. Compression is a good number, so you're fine there. It's not a bad idea to change the head gasket anyways due to these do leak eventually. They seal very well, but do leak given enough time/miles. It's a steel gasket with a black coating so dont put anything on it. Just clean the deck and each head thoroughly with a scotchbrite pad and brake cleaner. Blue loctite the bolts and torque to 24-26 ftlbs. It's a good idea to put the heads on and run it for about 30 seconds before you put the head cover on. When it's warm, torque the head bolts again. This will ensure a good seal, especially on that style of gasket. Once torqued a second time put it together, fill it with coolant, bleed it properly, and verify coolant flow.
Even though what you found is a problem, I dont think it's whats causing the popping. But it is a good thing to eliminate that problem. Keep me posted on how things go. -Polaris Doc
 
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