07 600 backfires at idle

[snowboatboy]

I have a 2007 600 HO that i just rebuilt completely, I set the rings yesterday and today I was going to take it out for the for the first ride on the engine, but when I went to put in on the trailer I noticed that it didn't sound quite right. After I put it on the trailer I noticed that it was backfiring at an idle an it wouldn't rev all the way up. So far I've cleaned the carbs, unhooked the TPS, and cleaned the exhaust valves. but none of these thing have made the slightest difference. Any one ever had or have any ideas on how to fix? Thanks

 

[mark]

problems at idle

Could your plug wires be reversed? Power valves upside down?

How many miles before the rebuild? I have the same machine with 1900 miles and wondering how long it can go.

Thanks

 

[snowboatboy]

cant get rpms

The machine had around 2100 mi on it when one of the rod bearings on the crank went. I did the rebuild myself and followed the service manual so everything is spec. I've tried everything that I can think of: TPS, cleaned carbs, cleaned power valves, cleaned and checked reeds, spark plugs, coil, cdi, but nothing has really made a difference. It seems like the backfire isn't is as much of a problem than the fact the I can't seem to get the rpms up, so that's what i'm trying to figure out now. Thanks for any help.

 

[Kraven]

The machine had around 2100 mi on it when one of the rod bearings on the crank went. I did the rebuild myself and followed the service manual so everything is spec. I've tried everything that I can think of: TPS, cleaned carbs, cleaned power valves, cleaned and checked reeds, spark plugs, coil, cdi, but nothing has really made a difference. It seems like the backfire isn't is as much of a problem than the fact the I can't seem to get the rpms up, so that's what i'm trying to figure out now. Thanks for any help.

1) Drain ALL the old fuel out of the tank and pour it into your daily driver

2) Replace fuel filter

3) Fuel pump "pulse" line possibly kinked, not supplying fuel pressure????

 

[snowboatboy]

So today I finally got a compression tester on it and it came up with 50 psi on both sides, whats up with that? i used spi pistons when I rebuilt and everything ive read about them says that they are good. but this is just wierd.

 

[NapaMatt]

Well Cyl walls are out of Round. Not true. Did you buy bigger pistons and have a Machine shop Bore them out??

tis the Problem ekk

 

[snocatn]

Were the pistons put in the correct way? With 50 psi per side I'd take the cylinders off and see what is wrong in there.

 

[fastpolaris]

So today I finally got a compression tester on it and it came up with 50 psi on both sides, whats up with that? i used spi pistons when I rebuilt and everything ive read about them says that they are good. but this is just wierd.

Can't be correct. Sleds won't even run unless each cylinder has 90 psi.

 

[blazer71]

Crankcase seals? Spray carb cleaner at them while it's trying to run and see if it effects the idle quality for better or worse? Well at least the PTO side

 

[snowboatboy]

ring scuffing

Finally got my head off and found the same type of scuffing that saskrmk had in a thread he posted a couple weeks ago, but mine is in both cylinders. link to thread. http://www.snowestonline.com/forum/showthread.php?t=337977
Whats up with this its like the rings didn't seat right, I really don't know what to do now . any help is appreciated. Thanks
http://www.snowestonline.com/forum/showthread.php?t=337977

 

[switchy]

The only thing i can think off is rings upside down and make sure ring gap is on the carb side good luck.

 

[j-gnar]

I put one of them on upside down and there was no freeplay on the ring so we flipped it and found there was markings on the upside and then they worked great when put on right. I also used spi pistons. Did you get new piston bearings they don't come with the spi kit. Did you get the cylinders honed out and the ring end gap set. The machine shop I went to said the gap was to spec on mine and nothing needed to be done but a light hone was done and he was very specific on which piston went to each cylinder.

 

[snowboatboy]

Im sure i got the rings in right because i put one of them in wrong to begin with and it just didn't work. still haven't figured out whats going on, but at this point im feeling like the rings didn't seat correctly. also does anyone know if oem rings will fit in the spi pistons? Thanks for all the help figuring this out.

 

[j-gnar]

Dumb question but you checked your plugs right? How does the head look?