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Discussion Starter · #1 ·
ok after overheating my motor i replaced the top end gaskets that i melted and that was it it seems to run ok but when i gun it it studders a little then takes off and on the top end i can only get like 8500 rpm for a while then it goes to like 75 and wont go back up when im holiding it wide open, i just cleaned the exaust valves thinking that was the problem. i have all the gaskets to take the motor apart and check for piston ring problems or stuff like that. should i just take it apart and look it over or is there another problem????

oh another possibility would it run like that if i accidentally put the high comp heads on and ran it with 92 octaine??? because after i took the gaskets off the high comps to put on the low comps i possibly switched them

help me!!!!!!!!!!! im so stupid!!
 

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Discussion Starter · #2 ·
by the way i did change to leaner jets to try and get rid of it, and put a new belt on. what else could it be??? im thinking it has to be motor problems, like bad rings or a bad gasket, but what do i know???
 

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khafner129 said:
by the way i did change to leaner jets to try and get rid of it, and put a new belt on. what else could it be??? im thinking it has to be motor problems, like bad rings or a bad gasket, but what do i know???
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What do the plugs look like after a WFO run? Have you done a compression test? What condition are the clutches in, old springs? I would think if you got the domes mixed up that could definitly be causing your problem, pull the plugs and take a reading.
 

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Discussion Starter · #4 ·
i will check compression tomarrow. the clutches are old, never touched them.
my plugs look ok a little black but not too bad i have put 700 miles on this year with no problem untill after i overheated the motor?
 

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A compression test would be the best place to start being you over heated it. If it has good compression and the plugs look good I would look to the clutches.
 

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Discussion Starter · #6 ·
compression is around 100 psi in each side, is that right??
our gage isnt the best and its hard to read. you think the clutch would make it bog down like that?
 

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khafner129 said:
compression is around 100 psi in each side, is that right??
our gage isnt the best and its hard to read. you think the clutch would make it bog down like that?
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Time for a rebuild. I would tear it apart and check the pistons, if they look and measure ok throw some rings in it and get back out there!
 

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yea def start with the compression. I tried to jet around my bog before I checked the compression and a ring let go. Now I gotta send the jug away to get fixed as well as buy pistons and a top end gasket kit.
 

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Discussion Starter · #9 ·
ok guys thanks alot. the rebuild is already in progress, its all apart, the rings looked a little bad but not horrible the piston had a little mark in it. so i hope thats what did it i will put it togeather tonight and see if it worked.
-kevin
 

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Discussion Starter · #10 ·
ok its back togeather now, i rode it a few miles in the field today and checked the compresion i get around 130 on one side and 115 on the other is this right? does it take time for the rings to set and get good compression? what am i supposed to have??
 

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No, that is not good at all? You have a 440? Which head is on there now, high or low compression? There cant be more then a difference of 10 from cylinder to cylinder so you have a problem there. Did you replace your piston with the skoar? My 600 HO(04) started running like dirt, so i checked the compression. 100-102. Toar the engine out, replaced the rings, had my cylinders honed, e.t.c. The whole nine yards to be safe, im now getting 149-150. I would prolly want to look at the pistons for skoars(liek you said yours had), cylinders, everything. While your at it take a brief look at the bottom end. Might as well do it all so you dont have to take your engine out 5 more times.

Aswell, it doesnt take anytime at all. When I installed my new rings and put the engine back in my sled, I did a compression test right away. You should ride it for about 20 miles to break it in, and then put a full tank through with a little more oil and vary your throttle positions, e.t.c(DOnt hold it wide open for more then 2 seconds). Aswell, let it cool down once and a while, dont ride it for 3 hours straight. Hope this helps.
 

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Discussion Starter · #12 ·
ya i have the low compresion heads, and replaced both pistons and rings, the cylinders looked fine so i left them alone. i must have a base gasket leak no?

it does seem to run ok so far, but i never really opened it up more than half throttle.

man i really dont want to tear it down again but it looks like im going to have to.

hey could a ring upside down or something stupid like that do it?
 

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Discussion Starter · #13 ·
could it be from not enough locktite 518 on the base gasket?

i think i will try to put my new cylinders on too incase one is warped or something but they look good to me
 

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Discussion Starter · #14 ·
one more question!! sorry to be such a pain in the "edit for bad language"

do yo have to get the cylinders honed? i didnt think so becouse they are nickel plated or whatever, but my dad said you used to on the old ones
 

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khafner129 said:
one more question!! sorry to be such a pain in the "edit for bad language"

do yo have to get the cylinders honed? i didnt think so becouse they are nickel plated or whatever, but my dad said you used to on the old ones
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yes you do! Just a light ball hone will do the trick! not too much though!
 

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Discussion Starter · #16 ·
ok i got them honed and will put them on tonight, i will know tomarrow if i have good compression.

do i need to put the exaust on to do a compresion test or no?
it would be easier for me if i dont have good compression i can take it back apart that y-pipe is a pain to put on is there some kind of special allen wrench to get it off? i kindof made one by cutting one off but it dont work that great
 

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Discussion Starter · #17 ·
got it it was an upside down piston ring that gave me 115 psi instead of 150 now i have 149-152 thats good right?
 
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