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Discussion Starter · #1 ·
We have a 98 ZR600 EFI, it just hasnt been the same since we bought it, when we first got it had such a crisp throttle, when you hit the gas it almost tore your arms off. Now it just bogs around at low end and never really does much better higher up. We did the stator twice last year, so we took it to a shop and they tested everything out and said all was good, and it ran the rest of the year just barely ok though. One day we had almot like it lost one cylinder, it was running on one so we put plugs in and that did it for a little bit then it did it again, and came out of it. Also did some backfireing to the point it popped the exhaust off, the flange wasnt very good, and actually has broken off completly now, so maybe thats the problem.

Anyway we got all the sleds out and were working on them and we got to this one, and we started it up and it ran ok, still acted boggy, let it warm up and ran a comp test. It had 30 on the mag side and 60 on the pto (I double checked the tester on my 700 poo it had 120 on both cylinders, also check on our z440 it had 110 on both). It had also been burning some water, maybe 1pt per 50 miles. So we figured head gasket/o rings. So I pulled the head off and the everything looks good, o-rings are great everything looks clean no scorching/scoring on anything.

What is causing this? Base gaskets, crank seals? Could the exhaust flange cause it, we did cover it with high temp silicon.

I have a generic service manual for all cats 90-98, and it does specifically categorize for each different sled. Been reading for the last half hour fiding abslutly nothing.

Sorry for being so long, I figured the more info the better.

Thanks
 

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Discussion Starter · #3 ·
arctic_cat_man1 said:
is it back firing and dieing alot?
never had it die, but it has back fired a fair amount at times, not always though, when i ran it the last couple nights it never backfired once, but last year when riding it would sometimes
 

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For compression that low, do pistons and rings.

Since you'll be replacing the base gaskets anyway, if they were leaking you'll have fixed that problem as well.
 

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Discussion Starter · #5 ·
Ugly_old_Poo_kid said:
For compression that low, do pistons and rings.

Since you'll be replacing the base gaskets anyway, if they were leaking you'll have fixed that problem as well.
didnt think of the rings, ill pull the jugs off and take a look at them
 

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Discussion Starter · #6 ·
well i checked the pistons and they seem like they have alot play, will just rings do it
 

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it might but i rarely like to just do rings especially if you are going to be riding it alot this winter, if it was more of a yard/beater sled i would say go ahead and just do rings.
 

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Discussion Starter · #8 ·
we arnt keeping it, we just want to get it going good enough to take it in to the consignment dealer, so anything that isnt neccessary and is expension we dont want to do
 

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Measure the cylinders and measure the pistons, then compare the difference in size to what the manual says is allowed.

If the wear is minimal, just do rings. But if it's anywhere near close to, or over the limit, replace the pistons as well.

--edit--

Just do the rings if you're going to sell it.. But in good conscience you must tell the buyer that they'll need pistons.
 

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Discussion Starter · #10 ·
what do you buy oem pistons? just wondering what the difference would be, there is about 4300 miles on, and i think the pistons seem really clean almost no carbon build up on the head or the pistons

looked up parts, 140 per cylinder to get the piston kit, 50 per cylinder to do rings, plus 40 bucks for a gasket kit, does this sound reasonable or to high
 

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I would buy SPI for trail sleds, and Wiseco for performance sleds.

I can quite you SPI or Wiseco prices when I get to my shop. But I'm guessing that it's a bout $65 a hole for SPI pistons and rings, and Gasket kit around $40 for Winderosa
 

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Discussion Starter · #12 ·
ya why dont you, i just came from mfgsupply.com and they were 90 a hole on a wisco set, we will definatly be doin pistons, jut took the jugs off and one piston has a pretty rough edge to it on the exhaust port side, however the jug is almost perfect dad claims he can feel a slight rough edge but i cant feel a thing, wondering what to do with them, the book says they are aluminum with a chrome bore, is this something special or nothing much, can we hone it or do we need a whole new jug

just found an spi kit on the and it was $65 a hole and a wiseco kit for $90 per
 

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SRP(smart recreational parts) lists yer SPI pistons for $67.11 each and a winderosa top end set for $54.00.

800-871-8966 if you want to call them.
 

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Discussion Starter · #14 ·
Ugly_old_Poo_kid said:
SRP(smart recreational parts) lists yer SPI pistons for $67.11 each and a winderosa top end set for $54.00.

800-871-8966 if you want to call them.
i found a winderosa kit for 40, it has exhaust, base, o-rings for the head, the 12 little o-rings for the head bolts and carb adapter seals, and that site also has the wiseco for 90, or OEM for 70

another question i have is about break in, what do we do to do it properly, were just doin pistons and rings, jugs should be alright, and then ofcourse new gaskets
 

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I had a sled that was doing the same thing put new plugs in and ran great for awhile. Took it to the dealer had them reseal the motor ran great for about 2 weeks then went back to doing the same thing. After a lot of money and aggrivation me and a buddy took the motor apart and found out it had a bad crank seal fixed that and never had a problem again.
 

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Discussion Starter · #16 ·
Firecatrider10 said:
I had a sled that was doing the same thing put new plugs in and ran great for awhile. Took it to the dealer had them reseal the motor ran great for about 2 weeks then went back to doing the same thing. After a lot of money and aggrivation me and a buddy took the motor apart and found out it had a bad crank seal fixed that and never had a problem again.
we thought about that, but finding a piston lookin like that is something took fix to
 

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Discussion Starter · #17 ·
so do pistons and rings and gaskets count as a topend rebuild or what else would be needed to call it one
 

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Discussion Starter · #19 ·
Ugly_old_Poo_kid said:
That's a top end...

Oh yeah, don't forget to hone.
alright ill make sure to do that[thumb]
 

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Discussion Starter · #20 ·
gaskets and pistons came today, got the cylinders honed, going out to assemble it right now, as far as break in the sheet that came with the pistons says, run 50:1 premix for the first tank, and no high rmp runs for first 5 hours of use, anything else you recomend that i should do
 
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