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Discussion Starter #1
Rebuilt my 94 indy 500 this summer after snapping the PTO end off. All new bearings & Wiseco pistons. Ran real good at startup. Finally got the clutches done, and took it out. I premixed the tank & made sure the oil pump was bled & working. Let it warm up for about 5 minutes & warmed up the track. It ran great for a while about 2 miles worth, then she started cutting out & back firing. I didn't hear any bang or clunks. It pulls over just fine, no noise at all. Looked in the plug holes & pistons & walls look great. What could it be? I just don't want to tear it all down again if it may be something easier. Any thoughts / suggestions would be great.
Thanks
 

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Try new spark plugs.
 

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Discussion Starter #3
I pulled the plugs. They weren't drenched, but I didn't try new ones. Oh if it could be that simple. I will try them and report back.
Thanks for the reply
 

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Thats the same thing that happened to my indy 500, and I justed changed the plugs and it was fine. It sounds like an ignition problem though.
 

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Well, went out & put new plugs in. Two pulls & she fires right up. No unusual noise, runs fine. Had freezing rain all night & there was almost 1-1/2" of ice buildup over everything,so I didn't ride it, but that simple thing seems to have worked. Thanks ski-doo211
 

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Sometimes it's just that simple. A few years back my dad's old Yamaha wouldn't run at all. Plugs didn't look bad, replaced them and it was perfect.
 

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Discussion Starter #7
Yep, Sometimes it's the simple things that are most often overlooked. As often as I've had to figure that out the hard way, you'd think I'd learn. [B)]
 

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Ditto, sometimes plugs just wear out or get corroded to the point where the spark arcs, instead of going to the electrode it is dispersed over the head of the plug. It looks dry and good to go, but it won't run worth a crap
 

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Originally posted by Timber500
[br]Well, went out & put new plugs in. Two pulls & she fires right up. No unusual noise, runs fine. Had freezing rain all night & there was almost 1-1/2" of ice buildup over everything,so I didn't ride it, but that simple thing seems to have worked. Thanks ski-doo211
No problem, glad to help!
 

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Hey, what do you think cased your nubbin to break of the pto side, i had the same thing happen 3 years ago, and my dads freind said it was cause i had i pinned for to long, which i think is BS because i hadnt pinned it that day and the clutch broke off when i was on the breaks slowing down to take a rest. I think it was becaue the bushings that the clutch weights were shot causing one to stick open, but what do i know, im just a punk kid...
 

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Discussion Starter #11
Originally posted by SKYDE
[br]Hey, what do you think cased your nubbin to break of the pto side, i had the same thing happen 3 years ago, and my dads freind said it was cause i had i pinned for to long, which i think is BS because i hadnt pinned it that day and the clutch broke off when i was on the breaks slowing down to take a rest. I think it was becaue the bushings that the clutch weights were shot causing one to stick open, but what do i know, im just a punk kid...
Well I had heard rumors that the PTO end of those cranks were prone to break. When mine went I was trying to follow a 700 RMK up a decent hill in about 4ft of fresh powder. Had it pinned for a good solid 20-30 seconds. It was moving ok, but I think the deep powder was too much & it snapped. After looking at the crank, it looked like it was stressed cracked long before it snapped. There was slight rust in the broken area about 3/4 the way through. That run just finished it.
 

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Im thinking water in the fuel system. I run those "tampoms" in the tank. they actually work very well, but are only good for one year. Hope its just plugs, but Im leaning more toward H2O in the fuel system
 

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Discussion Starter #13
I had thought about water in the fuel, but it had a full tank with ISO heet, and was kept in a heated garage. I know thats not fool proof, but new plugs cured it. Funny, they looked nice & dry. I'm just glad it was nothing internal.
 
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