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Banshee tuning issues


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Ok here we go. I recently purchased a banshee with a bad topend put in two new weisco pistons. I also installed a cool head with 19cc domes and a adjustable timing plate. It has 300 main jets installed. I cant seem to get it to run right. Im running vp110 leaded fuel. It runs very rich dripping gas out of header. Backfires and also has no power! The timing is set +2 right now. Anything helps!

 

With my setup what is the best suitable degree of timing to run?

 

Any other suggestions on how to get it to run better?

 

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Whats you elevation?

 

What is your compression?

 

Have you thoroughly cleaned the carburetors,  checked float height, made sure not to mix up bowls.

 

Are you sure your carburetor slides are in correctly and not reversed? (Cutaway toward air filters)

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yes compression is quite low for those domes, should be around 160ish with those domes on a stock stroke/bore motor. Its probably very tired.   And as stated above your fuel octane is much too high. high octane fuel needs more compression to burn off hence the unburnt fuel in your exhaust. 125 will take premium pump gas.

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1.  You need to verify that you used the correct series of piston.  You may also want to check the squish clearance for the piston/head.  Check on this site to learn how. 

 

2.  Do NOT use your cranking compression values for decision on fuel type!!!  That will get you in trouble.  Indeed, with 19cc domes, you will need about 100oct thought I have run them on premium.  It should dial in fine with your fuel. 

 

3.  It would be great if we knew the exhaust duration.  Is this new porting?  Who did it?  I do agree that 125psi is low BUT what gauge are you using?  Does it have a schrader valve in the tip?  If not, ignore the value, you are not testing correctly. 

 

4.  Please remove air filter devices and look up the back of the carbs.  Slightly open the throttle and see if the slides are opening together.  Sounds like you have carb balance issues. There are also glass windows on the sides of the carbs to check slide height.  Read the manual on this. 

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