Arctic Cat Forum banner

1 - 20 of 28 Posts

·
Registered
Joined
·
65 Posts
Discussion Starter #1
I just put in a newer but used left cylinder and replaced both pistons and all new gaskets. The sled fired right up. I was so excited. My first rebuild seemed to have worked out great! As I let the engine run I noticed the left side was spraying gas out of the exhaust leak I have around the header. I felt both pipes for heat and only the right side was warm. Same with the spark pugs, the left was cold and the right was really hot. I pulled the plugs and checked for spark. They both worked the same.
I'm not sure if maybe some coolant went into the crank when it was pulled apart? Maybe taht has something to do with at? I just don't know what to do. Will someone please give me some advise?
Thank you
 

·
Registered
Joined
·
65 Posts
Discussion Starter #5
Brand new plugs though. I switched them out again just in case.
I also pulled them out and turned it over to check for spark and they both fired.
 

·
Registered
Joined
·
186 Posts
Do a compression check on both cylinders and then check reeds . Let us know. Had a race motor that was goofy ended up being bad piston with decent comp. but the piston was the problem!! Was ready to throw motor in the lake before that. Good Luck!!
 

·
Registered
Joined
·
65 Posts
Discussion Starter #7
My brother has a compresion tester so I'll see what it is. I just put in both pistons though and they looked great. They weren't new though, I bought them off E-Bay for only $10.50. Thought it was a good bargain. If it is a bad Piston wouldn't I beable to see something wrong with it? I'm not sure what it could be.
If compression is fine would it be benificial to swap both piston around to see if the other side stops firing?
Thanks
 

·
Registered
Joined
·
451 Posts
do a compresion test and go thru the carbs. Sounds a lil bit like the float is stuck open, and is dumping fuel into the cylinder, and it simpley fouls the plug out. Since it is leaking gas out the exhaust, that would be my first guess. Also, when you pull the plug, it is probably fuel soaked.

What made you do a rebuild on this anyways? Blown piston... melt down? worn out engine??? You need to adress the original cause of the rebuild, or you will be doing it again in short order. A dirty or improperly adjusted carb, is ussualy a leading cause of blown engines, or melt downs.Also, leaking crank seals, and gaskets.

Let us know, so we can further help you out :)
 

·
Registered
Joined
·
211 Posts
I would never buy used pistons no matter what the price or how they looked. Anyways the first thing is a compression test. If that is good, I would try cleaning the choke plunger on that cylinder's carb and then adjusting it down slightly to make sure it seats properly, it's a common problem. Just keep in mind no matter what you try the results won't be immediate because your botton end is full of fuel and oil now and it will take a few minutes of running to clean itself out.
 

·
Registered
Joined
·
6,671 Posts
I was gonna suggest looking at a fuel related issue. Chokes or needle stuck, flooding it out, will cause that sort of symptom.
 

·
Registered
Joined
·
98 Posts
Hmmm...if you had raw fuel sprayin out the exhaust, I'd have to say that your carb is dumping fuel in maybe float level not right or stuck float valve. Is this a carbed sled even?

It might ne that simple. I have to say, using used pistons in a rebuild is askin for it.

Just sayin
 

·
Registered
Joined
·
737 Posts
If the compression looks good I would also do a leak-down test on the engine to make sure you don't have a seal going bad. I worked on one that we did everything to it and found a bad seal behind the stator.

Let me know if this helps Jeff
 

·
Registered
Joined
·
65 Posts
Discussion Starter #14
<div class='quotetop'>QUOTE (superjuice @ Dec 21 2009, 01:59 PM) <{POST_SNAPBACK}></div>
do a compresion test and go thru the carbs. Sounds a lil bit like the float is stuck open, and is dumping fuel into the cylinder, and it simpley fouls the plug out. Since it is leaking gas out the exhaust, that would be my first guess. Also, when you pull the plug, it is probably fuel soaked.

What made you do a rebuild on this anyways? Blown piston... melt down? worn out engine??? You need to adress the original cause of the rebuild, or you will be doing it again in short order. A dirty or improperly adjusted carb, is ussualy a leading cause of blown engines, or melt downs.Also, leaking crank seals, and gaskets.

Let us know, so we can further help you out :)[/b]

I rebuilt it because the left piston was just starting to melt down. The dealership told me it was possible due to the cracked intake boots and he tought it may also be a leaking crank seal. My brother in law said he doubted it was the crank seal beacause it ran soo good. He said they will usually run fast with a leaking crank seal. He thought the dealer was just trying to rob me so I brought it back home and started tearing it apart. I didn't replace the crank seal but did replace all other seals and gaskets on the top end. Along with reeds and intake boots. My brother looked at the sled today and thinks it may be because of any left over water or excess gas and oil in the bottom end. He said I should get my idler wheels installed and just ride it for a while to see if it clears up.
Let me know if you think this is a bad idea.
Thanks again everyone for your advice. I'm working on it and hope it will be ready for the next snowfall.
 

·
Registered
Joined
·
451 Posts
ummm ya, thats a bad idea.There shouldn't be any left over water or oil or gas in the bottom of the engine. Thats just asking for more problems.And if it isn't running now, chances are its not gonna run later.Trying to drive it until it clears up, is gonna do more harm then good, and chances are real good, it simply won't go anywhere.

If there is coolant in the crankcase, you need to remove it, either by draining it, if there are drain ports on it, or by removeing the spark plugs and spinning the engine over alot.

But this does sound alot like a fuel issue, and the smart move is to go thru the carbs, make sure they are clean and that the floats are adjusted properly.Also, make sure there is fresh fuel in the sled.

Oh, and ummm seals wouldn't have been a bad idea, for peace of mind. The extra lil bit of time, and 10 or 20 bucks for parts, is well worth it.Unless you know for a fact, the seals were good.
 

·
Registered
Joined
·
65 Posts
Discussion Starter #16
<div class='quotetop'>QUOTE (Funoutfitters @ Dec 22 2009, 10:49 AM) <{POST_SNAPBACK}></div>
If the compression looks good I would also do a leak-down test on the engine to make sure you don't have a seal going bad. I worked on one that we did everything to it and found a bad seal behind the stator.

Let me know if this helps Jeff[/b]
What's a leak down test and how do I do it?
 

·
Registered
Joined
·
65 Posts
Discussion Starter #17
I guess it's more of the cost of labor. When the dealer said he was going to replace the crank seals that's where most of the labor was going to come into play. The total price on the repairs and labor would have been $1,900.00 I didn't pay that much for the sled. If I would have spent that much I could've bought a newer sled. :D That's when I thought I would save money, do it myself and see how much I could buy off Craigs List and E-Bay. I have no idea how to change a crank seal and I heard it was a pain. For a rookie like myself I thought I should just stay away from that. I will look for drain ports, I never thought about that. I just didn't want to take the motor out and dump it so I left it in thinking it will all blow out. But someone mentioned a leak down test, I never heard of that. How does one perform a leak down test?
 

·
Registered
Joined
·
127 Posts
you buy a kit to put compressed air into the cylinder, remove air source and watch the gauge to see if you loose pressure.
 

·
Registered
Joined
·
4,009 Posts
To find a leaky seal you would need to do pressure test, like others have said. The dealership is going to want to split the case and replace the crank seals and the intake flanges and charge you $70 - $90 and hour, or whatever their shop rate is, because they don;t want it to come back for the same problem with another toasted piston. They may also be including a replacement cylinder for the melted side.

Sleds always run real good, better then ever, right before they burn down. A leaky crank seal, or intake flange will not let you know something is wrong gradually. You will almost always find one of those have failed because you have experienced a lean burn down, melted a piston and possibly ruined the cylinder.

It is easy to check the intake flange by removing the clamping band and inspecting the rubber for cracks and checks. If cracked, replace with OEM flanges, not aftermarket. MAG side crank seals are well protected behind the magneto and stator and don't tend to go bad as frequently as PTO end seals. A pressure test will be needed to test the MAG end seal. You can test the PTO end seal with the engine idling by spraying WD-40, or the like, on the seal and seeing if the idle speed changes.
 

·
Registered
Joined
·
65 Posts
Discussion Starter #20
OK did a little carb work, now the left carb has a stuck joke. I can't get it out for the life of me. It's freed up to a point of being able to move up and down but I still cant get it out. Cleaned both carbs, the had a lot of build up in them. Checked floats, jets, needle etc. Everything looks good now. Took it for a spin and it seems to be only running on one cylinder and won't idle alone without giving some throttle. Now the right cylinder seems to be running rich while the left is running hot. Not sure where to start.
I still haven't bought new gas for it. I bought the sled a couple months ago and don't know how long the gas has been in there. Would that make that big of a differance?
I don't have the equipment to do a leak dow test so what other ideas do any of you have that I haven't done?
I guess I should mention it has aftermarket dual pipes. I don't know if the carbs have been jthose pipes or not. Someone did a little work on them but I wrote down the numbers off the jets and needle to see if they are still stock. I haven't checked it out yet but will do right now.
 
1 - 20 of 28 Posts
Top