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Motor Question


bansheeigo

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Hi guys,first time on this forum,i opened up the head of my banshee and found that the left side piston had a hole on top of it and then looked at the right side and it almost started to have a hole on that side too,my question is why did it have a hole on top of the piston,i was thinking that my water pump went out and got too hot.

It needed new pistons anyways.3 1/2 years with these pistons.What do you guys think what made this happen? :huh:

97 banshee

coolhead 21cc domes

wiseco pistons (.020)

207 above sea level

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A hole in the piston is from detonation. With 21cc domes and a stock bore W/no porting, W/no timing advance or up to about +3 advance or so you should be able to run 91 octane pump gas without detonation issues. If you ran it with lower than 91 octane fuel or the fuel sat in the tank for too long and went bad this may have caused your detonation problem. You may have ran it too lean on the mains which could also lead to detonation, or a combination of lean and low octane/bad fuel. Make sure the case is clean of any piston fragments/debris before throwing another set in.

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Too much air, not enough gas------------------------>JETTING

Buddy's right about the bad old or dirty gas. It only takes a speck of dirt in your jets to pop a piston.

Have someone take a looksy at your carbs.

Someone who knows their shit.

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