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Replace 4 mil base plate


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Hey everyone!! New banshee owner on this forum. I picked up a really clean 1997 with a 4 mil 403 stroker kit installed. The guy did a great job on the build, and even replaced the tranny gears while he was in the bottom end. I grabbed it with only 3-4 tanks ran through her, and she's wonderful!! My question is, what do i need in particular to replace that garbage base plate so i can get the 2 mil on the up stroke and down stroke rather than 4 mil just on the dowm stroke. Do i just need a cool head, or do i need port work, or both with a new gasket kit of course. I searched and didnt see this question answered. Any advice or help is greatly appreciated!!! Thanks in advance, and happy, safe riding banshee buddies!!

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Hope this will help you a little bit. As you can see, rod length, spacer plate etc. have nothing to do with strokes.

 

Stock banshee have 54mm stroke. A +4 crank mean that the pin is 2 more mm away from the center of the crank, so it give you 2mm up and 2mm down more stroke for a total of 4mm.

 

Feel free to ask questions if it's not clear enough.72bac94e34adbff242fced466f1e98a5.jpg

 

Envoyé de mon SM-G935W8 en utilisant Tapatalk

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Yes, you will need base gasket, ttpicaly 0.020"

 

Now, did you ever see the inside of a shee or any other 2 strokes engine?? There is 'windows' where the fuel came in and the exhaust goes out. The height of those windows have to be adjusted to the new stroke/travel of the piston. Thats what we call porting. It's a rough explaination but you should get the point.

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I understand that the porting would be off, but for now i can atleast remove the base plate, put in the new gasket, and install a new head with stroker domes right? I'll just get her ported and polished this winter. I just dont trust that base plate. Seems like one more spot to lose air. Thanks again for all the help guys.

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I threw a spacer plate motor together and never checked or knew porting timing or compression and it had a stock un molested head on it. Ran on pump gas and would run as good as my (at the time) unported probably poorly tuned 392 Cub. It ran for years and years then the guy sold it the Banshee with motor parts still on it.

I'm not recommending to be as careless as I was with that motor, but if it is running good now and does not have an air leak it is fine.

 

 

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