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Low compression causing no "powerband"?


sp1tekiller

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My Buddy's Banshee will NOT get up into the meat of the power at all. We chased all the fuel issues we could and eventually found the compression was only 90 and 95. We're in the process of doing the top end, but still wondering if there is another issue causing the bogging/lack of getting into the power. I mean, other than the high rpm lack of power, this thing ran great. Didn't expect the compression to be so low.

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My Buddy's Banshee will NOT get up into the meat of the power at all. We chased all the fuel issues we could and eventually found the compression was only 90 and 95. We're in the process of doing the top end, but still wondering if there is another issue causing the bogging/lack of getting into the power. I mean, other than the high rpm lack of power, this thing ran great. Didn't expect the compression to be so low.

 

Don't forget to verify the jetting. Too fat will cause it to run flat or fall off on top.

 

SP

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The jetting was/is good. However, it has slightly chipped reeds, a cracked intake boot and a messed up airfilter cage. Everything is going to be replaced, it seems that it sucked some sand into the cylinders. We're hopeful the rebuild and replacement of the parts I mentioned will get it back on track.

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The jetting was/is good. However, it has slightly chipped reeds, a cracked intake boot and a messed up airfilter cage. Everything is going to be replaced, it seems that it sucked some sand into the cylinders. We're hopeful the rebuild and replacement of the parts I mentioned will get it back on track.

 

I dont think 95psi will cause your banshee to not rev out . Get your reeds and new boots and see what that does first. If it fixes your problem. then rebuild your motor if you want. 95 is pretty low. buty it should still run "decent" i would think.

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90 - 95 is low I had a cr80 and it was only around 90. And it would run but once u wanted to get on the gas it was a turd with no power band. I rebuilt it and it screamed and it has a good powerband. I can't forget what the compression was after the rebuild on the cr 80. I was told the banshee should have around 120 compression.

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90 - 95 is low I had a cr80 and it was only around 90. And it would run but once u wanted to get on the gas it was a turd with no power band. I rebuilt it and it screamed and it has a good powerband. I can't forget what the compression was after the rebuild on the cr 80. I was told the banshee should have around 120 compression.

 

you are correct 120 comp but it still should run decent have you checked for a air leak?..also the reed will cause it to bog and be hesitant so for sure change those and make sure u do a air leak!

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you are correct 120 comp but it still should run decent have you checked for a air leak?..also the reed will cause it to bog and be hesitant so for sure change those and make sure u do a air leak!

 

No air leak in the cr80 it was just low compression. I already rebuild it and it runs like new the compression was around 90. And after the new piston and rings it rips good I sold it to a friend for a play bike.

And he likes it. But thanks.

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No air leak in the cr80 it was just low compression. I already rebuild it and it runs like new the compression was around 90. And after the new piston and rings it rips good I sold it to a friend for a play bike.

And he likes it. But thanks.

 

 

oops sorry i was responding to killer but was agreein about the compression with you...which my lil 4mil had 130 comp and suppose to be 185-190 and the bike screamed but was bout to explode too..lol..so lower compression shouldnt hurt it unless you are talkin really,really low comp but 90 from 120 dont sound that bad to me,but if the bike has a air leak that would cause it to run like shit..jmo..trust me ive had a few bikes that done this and we chased it for months and was suckin air at the key way on the crank on my triple!//..

Edited by tripledsracing
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