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Hey guys, I’m back lol. Sooo, things went well for a while and then I lost compression and it was running on one cylinder again. Basically fired it up for the first time this year and tore around the yard, it died on me, fired up again and died and was locked up. Spun the clutch backwards and freed up the motor. Fired it and got it back into the garage. So I’ll try to post as much information so you guys can help. Ok so I tore the motor down, cylinders were scratched up and pistons had worn. Cleaned the cylinders up, had them honed, and now has a fresh top end, has good compression again. Tore into the carbs and found the throttle cable was not hooked to the needle valve, figured that was what caused it to run one cylinder and blow the pto side. So I got it all back together and fired it up. Still running one cylinder! Sooo, I switched the cdi box with my buddies and still nothing, new wires, plug boots, everything. Now here’s where I’m confused, when I pull the pto side plug, smoke comes out of the cylinder as if it was getting spark, but the plug is completely saturated with oil/gas. So I’m thinking stator causing weak spark and not firing the cylinder like it should, or a carb issue dumping too much fuel. I ordered a stator just in case because upon start it did backfire once, so maybe a could is burnt out on the stator? I’m lost. I’m pretty sure it’s a carb issue or a stator problem. Anyone have any leads. I’m pretty mechanically inclined but not quite sure what I’m looking for in the carb that could be worn causing it to make the sled act like that. And how can I test my stator. All help is greatly appreciated!
 

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Discussion Starter #2
i should also note that when you pull the wire off the pto side and tap it to the plug you can hear the cylinder fire for the faintest of seconds then goes dead again
 

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2020 Indy XCR 800 129", 2019 Indy 850 129", 2011 IQ Turbo 121"
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Since I haven't seen anything previous about your situation, I'm going to ask questionsl Sure those pistons and cylinders aren't chewed up because there are crank bearings coming apart? Having an engine "free up" by spinning it backward can also be a sign of a crank bearing failure.

So, sounds like the PTO side isn't firing? First, understand that the CDI fires BOTH plugs at the same time on that engine. You have spark and if it runs on the MAG cylinder, the ignition timing is at least in the ballpark on that cylinder. You will want to check the crank indexing and also look for an air leak (bad crank seal, cracked carb flange, etc) on that dead cylinder. If that cylinder was drowning in gas, check to be sure the choke (enrichment) isn't stuck open or there is a needle/seat or float issue.
 

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Since I haven't seen anything previous about your situation, I'm going to ask questionsl Sure those pistons and cylinders aren't chewed up because there are crank bearings coming apart? Having an engine "free up" by spinning it backward can also be a sign of a crank bearing failure.

So, sounds like the PTO side isn't firing? First, understand that the CDI fires BOTH plugs at the same time on that engine. You have spark and if it runs on the MAG cylinder, the ignition timing is at least in the ballpark on that cylinder. You will want to check the crank indexing and also look for an air leak (bad crank seal, cracked carb flange, etc) on that dead cylinder. If that cylinder was drowning in gas, check to be sure the choke (enrichment) isn't stuck open or there is a needle/seat or float issue.
yes the pto side is not firing. A little back story, the I had the sled out last season and we were ripping pretty hard and I let off the gas and it started running one cylinder. I got it home and let it sit for a few days, after it sat it fired up and ran both cylinders no problem. I put another 100 miles on it actually with no issues. First time out this year warmed it up went around the yard a few times, cracked it and it died on me, fired it up and headed for the house it died, this time locked. I freed it up and got it in the garage. When I tore the top end open the cylinders had some wear from the piston.Anyways I got it out back together, fired first pull. Has good compression in both cylinders but it’s not firing pto side which is why I think I fucked it up in the first place (limping it home on one cylinder). I believe the bottom end is ok, I didn’t see anything to indicate otherwise. From what I have read though is the stator can be on its way out and cause bad spark? But I also understand that if one side has it, both should. And it seems like it does because when I pull the plug after running smoke comes out of the cylinder. I am starting to think I have a carb issue, but like I said I don’t know where to start, how to tell if a part is worn in there. I’ve pulled up the diagram from a parts warehouse but just can’t figure out what would cause this issue
 

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Discussion Starter #5
Also, I pulled the bowl off the carb, and the float is moving freely so I don’t think that it’s stuck. But I’ve heard that parts can be worn. Now if I ordered a carb rebuild kit, would I be able to replace said parts that are worn and stop this issue. Basically it fires both cylinders on start up but a few seconds after it goes dead and fouls the plug
 

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pulse line to the fuel pump? if there is gas in the line possible pump failure. that will suck it right in the bottom , and you can't get past it. had one saturday on a ski doo saturating one cylinder
 

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Also, I pulled the bowl off the carb, and the float is moving freely so I don’t think that it’s stuck. But I’ve heard that parts can be worn. Now if I ordered a carb rebuild kit, would I be able to replace said parts that are worn and stop this issue. Basically it fires both cylinders on start up but a few seconds after it goes dead and fouls the plug
What comes in a carb rebuild kit?
Which parts do you believe are worn?
Have you pressure tested both carbs?
 

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pulse line to the fuel pump? if there is gas in the line possible pump failure. that will suck it right in the bottom , and you can't get past it. had one saturday on a ski doo saturating one cylinder
Can you please explain this a little more to me? How would the pump fail if one cylinder runs? I’m confused
 

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What comes in a carb rebuild kit?
Which parts do you believe are worn?
Have you pressure tested both carbs?
I have not pressure tested the carbs no, how would I do that? And the rebuild kit is from MFG supply. 26-1986 Polaris Aftermarket Carburetor Rebuild Kit for Some 1998-2000 600 & 700 Model Snowmobiles | Snowmobile Parts | MFG Supply is the link. I’m not sure but I’ve heard needle/seat issues can cause it to not run on a cylinder? I was going to swap carbs and see if it follows to the cylinder. I just also don’t want to run the motor too much with a fresh top end while I’m trying to seat the rings, just a frustrating issue lol
 

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Purchase a pop-off pressure tester for carbs..find it on-line. Do this first.
Don't waste your money on that carb kit.
 

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Purchase a pop-off pressure tester for carbs..find it on-line. Do this first.
Don't waste your money on that carb kit.
ok, so say I pressure test them, what am I looking for and where do I go from there. Sorry I’m learning as I go but I catch on quick lol.
 

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2019 850 Pro S S.B. 2006 600 Fusion
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Those had Keihin carbs, notorious for having the float pins get loose due to the wear inside the holes where the aluminum stanchions hold them in position. The holes get oblonged, and the pin doesn't let the float seal the inlet valve correctly. You might need to replace the carb. Also, the inlet seats are integral with the carb body, and are non-replaceable. You could try new needles, but if they still leak, another reason to replace the carb. It can be hard to find good carbs, I had a slug of 'em until I decided to just switch over to the Mikunis. Some creative adapting is needed to do that switch job, however.
 

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One more thing... when it locks up, yank the spark plug out of that cylinder, and see if a bunch of fuel shoots out. Make sure your ignition switch is off first... hydraulic locking, because liquids don't compress... air does.
 

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One more thing... when it locks up, yank the spark plug out of that cylinder, and see if a bunch of fuel shoots out. Make sure your ignition switch is off first... hydraulic locking, because liquids don't compress... air does.
thank you, see this is what I think I am facing as far it being a carb issue and not a electrical problem. I’ve been looking for carbs, and I have found some on eBay for about $190 for the pair, says they are in good mechanical condition. As far as locking up, it hasn’t done it since I did the top end. I just pulled the screw under the exhaust to see if the crank had gas in it and not a drop came out, so I don’t think I have gas in the pulse line crossing the fuel pump issue off. I think this is solely a carb issue. Thank you guys for the input.
 

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Those sleds had keihin carbs. Wasn't unusual for those pilot jets to plug, and you'd lose a cylinder at idle. We use to just chuck them out for new jets, as they were extremely difficult to clean, let alone keep clean.
 

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Those sleds had keihin carbs. Wasn't unusual for those pilot jets to plug, and you'd lose a cylinder at idle. We use to just chuck them out for new jets, as they were extremely difficult to clean, let alone keep clean.
I always used my ultrasonic cleaner which worked well for cleaning them, but I dis-liked those carbs a lot when compared to Mikuni round slides.
 

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Discussion Starter #19
Those sleds had keihin carbs. Wasn't unusual for those pilot jets to plug, and you'd lose a cylinder at idle. We use to just chuck them out for new jets, as they were extremely difficult to clean, let alone keep clean.
so above I listed a carb kit, is that what I would need to replace the jets and rebuild the carbs? Otherwise I found a set of carbs for 150 I was going to buy and swap them. Thoughts?
 

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I always used my ultrasonic cleaner which worked well for cleaning them, but I dis-liked those carbs a lot when compared to Mikuni round slides.
appreciate the info,I see guys have swapped for the mikuni carbs. What all does that entail to make the swap
 
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