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Discussion Starter #1
Ok, some of you may of seen my topic about my brother crashing his 99 Formula Z 583. He sold that and got $1000 american for it. Well, he recently went to an auction and got a 2002 MXZ 500 with 350 miles on it for $3400 american. Immediately we started having problems. When we got the sled off the trailer the sled would bog down when hammered on from the start, and then run great, but now the sled barely goes 40 and sounds really sick. We took it out to our mechanic and he thought he would be able to figure it out, but he doesnt know either. He said he put new plugs in it, ran great out to the end of the field, turned around and became sick again. He took the fuel pump off his 2000 mxz 500 which runs great, and it didnt fix the problem. He took the motor apart further and found the pistons still have silicon on them from shipping. The airbox is also clean and the carbs have been cleaned. Please, this is a big problem and if you have any ideas, please tell.

P.S. Sled has was not ran in a long time until we bought it because it was smoking relaly bad when started up at the auction, and has now stopped.
 

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What do the plugs look like when you take them out, check the carbs again, and the oil pump setting.
 

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Jokester886, which auction did you buy it at? I hope not White****. I don't want to say the name as they sell alot of junk there. I had a friend buy two sleds there, one blew the crank seal 1 week later, the other blew a piston 2 weeks later. Hope your not in that situation. As far as help, have you done a compression test? Where did it come out at??
 

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Discussion Starter #7
Well it was so cheap because the thing doesn't run. We took the gas tank off and checked for kinked lines, nothing. We tested the stater for any electrical problems, everything was in the right voltage range. We even heated it up to see if that would throw the numbers out of wack, but didnt. The last thing we can think of is the "brain", the black box next to the air box, is bad. We are going to get another one to test it out and see if thats it. This sled only seems to be bogging down after it gets warmed up.
 

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Discussion Starter #9
Originally posted by zackattack
[br]I know it only has a few miles but check the fuel filter and the tank vent lines.
Well when it stalls, you can start it right back up one pull, so there is gas getting to it. It has to be electrical
 

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What kind of temps is this happening at? Same temps, warmer, colder? I hope this doesn't sound dumb, but I had similar symptoms w/our Indy 500's. They would bog down, and at full throttle, would just barely engage the clutch. They would only do this in warmer temps. We'd adjust the needle e-clip positions and then they'd run fine. I think we adjust the clip "up." That was on roundslide carbs, I'm not sure how you easy this is to do on flatslide, if that's what you have. On the roundslides it was VERY easy. Good luck solving the problem, and I hope you can figure it out. Even more so though, I hope you didn't buy a P.O.S. from a shady auction.
 

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Originally posted by Jokester886
[br]
Originally posted by ZRT600
[br]What do the plugs look like when you take them out, check the carbs again, and the oil pump setting.
gray
I would be a little worried with "gray" plugs. They should be light to dark brown. Are you sure your oil delivery system is working OK?
 

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Discussion Starter #13
Lmdski- We posted at the same time... The sled was bought at Whitestar!... We never will go there I gaurantee it
Captainkirk- Sorry, I didn't mean gray, the plugs are ok, light brown.

Indy600x- All you can do with it is start it up cold, and make a run to the end of a field, and it acts up. If you hammer it, it will sputter and either take off, or stall, as soon as it stalls, it can be started right back up. So we know its not a gas problem.
 

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i got a 94 sup sport same problem it is the pistions they are easy to get an install also you could see if it is running to rich and burning plugs how much gas and oil do u go through?
 

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Put the rear end up on a safety stand and see how it runs. Keep the hood open and watch the primary and secondary clutch action. If it runs good on a stand, I would look for some sort of clutching or drivetrain issue. If it still farts on the stand, I would look for a motor or fuel delivery issue. Does this sled have powervalves?
 

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Discussion Starter #17
can you explain to me what powervalves are?

I dont think it does because I've never heard of them.
 

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WE HAVE SEEN PROBLEMS WITH THE REED VALVE CAGES COMMING APART INSIDE THE CYLINDER. IT SEEMS TO BE A REGIONAL PROBLEM SO FUEL HAS SOMETHING TO DO WITH IT.ALSO YOU MUST RUN RESISTOR PLUGS IN THIS MACHINE OR IT WILL AFFECT THE DIGITAL MPEM.DO NOT JUST LOOK AT THE REED BLOCKS , PULL THEM OUT, GOOD LUCK
 
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