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185psi of compression to much for reg. gas?


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Hey everyone this is my first post but I have a couple of guestions. My friend just got a 98 shee and it was time for a rebuild so we just got done and did a compression test to get a baseline and it was 185psi on the left and 182psi on the right.. The shee needed a crank and pistons, he put one off of ebay (stock stoke aftermarket) wiesco superstock piston. The bike is ported :whoa::whoa: out. it has a noss head (dont no which domes but probably the 16cc????)stock carbs stock airbox(k&n)stock reeds and cages. I have a 98 banshee to but is stock this is my second one first one was a 99 red and yellow pipes and filters about it. I have not had any dealings with a bike with this much stuff. I know that the crank will not hold up to the pressure.. The bike is overheating 20 seconds after it is started. Could the compression be the problem???? We are at sea level. It has 350 mains in it seams a little rich. And it also has a degree key (+4) and a timing plate set at (+4)..

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If your compression guage is right you are way high for pump gas. I don't know exactly what you mean by regular gas but 160psi is usually the cut off for 93 octane. I would strongly recommend not running the bike until you get the proper gas.

Yea I know its right because I just got done with mine also and it is at 135psi which is norm :confused: plus it came off of the MAC TOOL truck so its got to be right :D and 93 octane was what I meant.. Would that be the over heating problem!!

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Like the other guys said, that's way too much for premium pump gas. It shouldn't make it get hot after 20 seconds but it will probably make it grenade if it's run much. I'd look at the impeller if it's getting hot real quick. It does have coolant,,,,right? Is it getting hot that quick or just spitting coolant?

 

The advanced timing also increases the need for higher octane.

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Like the other guys said, that's way too much for premium pump gas. It shouldn't make it get hot after 20 seconds but it will probably make it grenade if it's run much. I'd look at the impeller if it's getting hot real quick. It does have coolant,,,,right? Is it getting hot that quick or just spitting coolant?

 

The advanced timing also increases the need for higher octane.

its spitting coolant

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After I put my noss head on mine was overheating the same way, it's not the head I just did not have the torq specs perfect so I cut a o-ring try getting a new oring kit and make sure they are all applied perfect greae them a little so they stay in the grooves, as far as the compression that is a hell of alot and if your runnung 16's at that elevation you'll for sure need some high octane

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Also, if the system is topped off with coolant and if there some some air pockets, it can spew some coolant when it is first warmed up.

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Does anyone else think the +4 key and the +4 timing plate seem like too much advance?

 

 

My thoughts exactly. +8 degrees sounds like too much timing to me. Not that this is the sole cause of the issue but possibly a contributing factor. Just my $0.02 worth.

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Rils is PROBABLY correct. O-Ring. Hot and spewing coolant aren't always related. Its probably one of the combustion chamber O-rings letting compression blow by into the colant system. As far as the timing and compression go, BOTH are fine lots of guys rum 10 degrees advance, JUST MAKE SURE you have high enough octane or DETONATION WILL RUIN your motor. 110 octane should be o.k.

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