Yamaha Banshee Engine work questions!! Please Help!!?

Question

Hello,

I am rebuilding my banshee top end and heres what im aiming for: The MOST out of my banshee engine without running race gas or messing with the bottom end.
I was thinking: Bigger carbs, v-force 3 reeds, .020 overbore, cool head with diffrent size domes. My question here is, what size carbs should i use, what size domes before running anything other that gas and oil mix and is there anything else i can really do to give it more power?

Thanks a lot!

Answer 1

Ben is giving you the correct answer.



Porting and polishing the ports is going to give you the most bang for the buck.



I would suggest sending the cylinders to Eric Gorr at forward Motion. He has been flow porting 2-strokes for decades and has it down to a science. http://www.eric-gorr.com/



Most air boxes are restrictive. This is done to hinder dirt, water and mud from entering the air box. If you open up your air box, you will allow the engine to breath better. Just don't get too carried away and pop rivet screens over any holes you make.



An after market silencer will also let the engine breath better. Pro Circuit and FMF both make after market non-spark arrested silencers.



The carbs will actually be a matter of choice. I like Bing, Keihin and Mikuni. I have actually had good performance out of of all of them. After the flow porting you can get away with a carbs that are 2-4mm larger than your stockers. If you go much larger than that, you will lose some low end grunt, but will gain it on the top end.



The cool head is only going to make a difference if you are racing in moto's that are over 20 minutes. If you are racing in motos that are over 20 minutes and you notice a decrease in horsepower, then and only then would I go for the aftermarket cool head.

Answer 2

Yamaha Banshee Engine

Answer 3

Send your cylinders off to Pro Circuit to get ported. A good port job is better than any big bore kit out there for 2 strokes. As for the cool head, it's pretty much worthless unless you are going all out and actually running race gas or riding your fourwheeler in 120 degree weather. If you're going to run pump gas just go with a good port job and the V force reeds. As for the Carburetors, I wouldn't spend money on anything other than a pair of Mikuni® TMX 38 carbs. A good quality carb is better than any size mediocre carb out there.

Answer 4

As Ben has said, to get more power from a 2-stroke there is no better way than to get the ports increased and well shaped, that is the same result as putting a better camshaft in a 4-stroke...