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Discussion Starter #1
hey yall. this is my first post on here.(sometimes i can be hard to understand when typing.)... my indy 500 has a hard time going over 60, it slowly creeps to 70, then nothing. it used to hit 85 no problem. now, this is what i got... pin er on the start, then past bout 45mph, the exhaust has a throaty sound, not brappy as usual. it hangs out at just below 7 grand on the tach. it usually goes 7,400rpm on WOT. lets say im just ripping around in the yard, its nice n snappy, torquey,.. just runs good, but find a straight-a-way, it just has no balls when WOT. i have also noticed there is air getting in the coolant. there is a very small tear-leak from the head, but that never caused a problem before. after riding less a mile, ill flip the pressure cap and air will come out and i get more coolant back. its got new plugs in er 250 miles ago, there burning equal and nicely colored. i run premium (fresh) and i use amsoil hp injector only. good stuff. i can say this, before i noticed this change in performance, i towed an old 70 skee horse up and down bumpy hills. one hill i het 8 grand on the tach. head was hot, hah like cook an omlette hot. it was fairly warm out tho.. like 30f -ish. idk if all this is easy to understand.:dunno: sorry if your confused. thanks :D
 

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Whats the compression, also look at your belt and clutches, Clean them up good and make sure your primary clutch weights are not hanging up. They can cause you some grief for RPM. As for the coolant issues I would reslove that, so you dont burn a hole in your piston. If its just head gaskets,I would replace them now before you have major engine damage.
Hope this helps
Good luck
 

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Discussion Starter #4
compression is: 130 mag, 135 PTO. we have a new belt for it, didnt put it on yet cuz we jsut has a snow melt :(. but we r getin some back. looked at the primary, its pretty clean, secondary slides back n forth pretty good. the head was milled (i forget how much was shaved off) but the head gasket isnt my worry. the water pump is where its leaking a lil. its the little o-ring seal where it goes, to or from, the engine. but hows it sucking air? didnt do that last year with the head gasket weaping a little.
thanks for a quick reply :D
 

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If you have a compresion tester for the rad, remove the rad cap and pump up the tester to (I think its no more than 13lbs) if it will hold the PSI you have no leaks, If it does leak down and no visible leaks are detected it could be leaking threw the heads. Can you smell collant burning when the engine is running?? Also pul the 8mm drain screws under the exhuast ports on your engine block, and look for coolant when it drains, ( I use a small cup or cap to catch the liquide so that the coolant will show up on top of your fuel and oil) Also change that O-ring on your water pump. Have you looked at carb boots and crank seal on the PTO side for craks or leaks, You can spray some brake clean or starting fluiud around the crank seal while the engine is running, This will tell you if your PTO crank seal is bad, Your RPM's will climb if the seal is sucking air.
That all I can think of rite now,
 

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Discussion Starter #6
the rad cap is like a 19-22lb cap. my dad wants to change it to a lower psi cap. i say keep it the same, theres a reason why polaris picked that cap for that sled. we'll check those other things later tonight. alright, thats for your help and your quick replies. ill post up if we get er runnin like a beast once more, thanks again for your help :)
 

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Discussion Starter #7
hey guitarman: gettin back at ya, we cleaned the carbs (pointless cuz they were clean), they are both in sync. pulled the case plugs, and there was a lil oir that came out with no coolant in it. i took er for a ride today, and it still boggs at roughly 6,500rpm, and still tops at 60mph. somehow sometimes ill get it at 7,500rpm. which is the max rpm for this engine (haha, even though i had it buried at 8 grand.). and i think i noticed the lights were a lil dimmer on the dash. hmm... tell me if im right on this now, these could be the next things to check: stator, cdi, fuel pump.

-thanks for helping.
 

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Discussion Starter #8
oh i noticed ur username, what kinda guitar do you have? i have a yamaha fg700s, and a washburn dk20cet.
 

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if your sure your clutches arent the problem (cleaned) it seems to me you may have a fuel supply problem.
Carbs are cleaned, but something might be keeping your engine from getting all the fuel it needs when its working hard.
I would check your fuel lines, filters, pickups and do a pump test.
I had a similar issue, ran awesome on very cold days or just screwing around, but on the long streches or pounding thru powder fields i was feathering it around.
My issue was the air box squished the fuel line from the tank to the pump!!!!
It cost me two top ends and countless hours trying to figure that out!!!
 

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hey guitarman: gettin back at ya, we cleaned the carbs (pointless cuz they were clean), they are both in sync. pulled the case plugs, and there was a lil oir that came out with no coolant in it. i took er for a ride today, and it still boggs at roughly 6,500rpm, and still tops at 60mph. somehow sometimes ill get it at 7,500rpm. which is the max rpm for this engine (haha, even though i had it buried at 8 grand.). and i think i noticed the lights were a lil dimmer on the dash. hmm... tell me if im right on this now, these could be the next things to check: stator, cdi, fuel pump.

-thanks for helping.
Did you ever get a new belt and or check the belt deflection? Is it a little boggie out of the hole? A narrow or loose, (belt deflection) will generally kill low and high end. The middle is usually OK.
 
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