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Discussion Starter #1
anyone have anything negative to say about the Wiseco 300cc big Bore kit? I am thinking about getting it
 

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i have herd from more than one it eats up starters. one guy on here even can up with an idea of useing a chain saw compresion release machined into his head to over come the problem. also herd they blow head gaskets?:confused:
 

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If you get higher compression piston, it will eat up the starter. You should be fine if you keep the stock compression... maybe?
 

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Discussion Starter #4
I think with any engine work it makes to motor unreliable and you will have to rebuild it every year...I just want some more power and a Big bore seems like the cheapest option right now
 

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big bores are fine just be sure that everything is machined right and that you invest in some head studs
 

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Discussion Starter #6
thanks for the info...I am having a guy thats pretty well known for his machine work do it, he came recommended
 

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Discussion Starter #8
Ray Franz
 

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Discussion Starter #9
I changed my mined...franz said a big bore kit without any top-end work would be like throwing my money out a window. Franz said to get a high compression piston and use race fuel, so I got a 12:1 JE piston
 

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I wouldn't say it makes it unreliable. Only unreliable if it goes too long without a rebuild.
 

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Remember,the thing that holds the horsepower down the most on this motor is the two-valve head.So,whatever you decide to do,have some headwork done. Port,polish,bigger valves,etc.If you leave the head stock, it is only gonna flow a certain amount no matter what else you do to the motor because it has to flow thru the restricted head.Scott.
 

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question for you fellas...I am removing the cylinder head and attempting to ensure TDC. I am setting the "I" mark on the pickup coil rotor with the stationary point on the crank case cover. When looking at the camshaft sprocket it's "I" mark is off by 180...could Yamaha have assembled it this way? I have rotated it a full cycle to check and it ends up the same. Ideas?
 

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Nevermind...ran it around a few more times and it checks out with both on the mark. Wheew thought I was losing my mind.

Now the cam sprocket bolt is giving me hell...won't budge...plus a pain in the a$$ to do while holding the cam in position not to lose TDC.
 

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Discussion Starter #14
For the money I have to play with, a new piston seems like the best option right now
 
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