Big Bore Power Help

[BOWTIEKV23]

I got a good deal on a set of sleeves and heads. as of right now i have a set of sleeves put in the heads and forged pistons from vitos

it is at 68mm. i was looking to get a port job done on the heads if it is worth it seeing that ive read that people say you can not do too much with the fact of how small the transfers are.

 

Primary Use is Aggressive Trail, Little MX Fun, All around i would say more of a play toy.

 

So all in all my question is can i get some opinions in which direction i should go.

What Pipes?

What Carbs? 30mm?

Would a 4mil crank be a good idea?

Play Port? From Which Machinist?

Any opinions would be greatly appreciated

just trying to get some ideas

[jbooker82]

So all in all my question is can i get some opinions in which direction i should go.

#1 What Pipes?

#2 What Carbs? 30mm?

#3 Would a 4mil crank be a good idea?

#4 Play Port? From Which Machinist?

Any opinions would be greatly appreciated

just trying to get some ideas

 

I would get them ported. People Claim that big bore sleeves are junk because they make the transfers smaller. Most of the people that say that dont have 1st hand knowledge. They are just repeating what they read somewhere. Big Bore Sleeves are not the most economical way to make power, but by the sounds of it you already have them installed.

 

#1 It all depends on what type of port job you get. If you get just a play / trail port I would go with T5's. If you get a Dune port I would go with a set of CPI Small Bore pipes. If you get a Drag Port then I would go with Shear's.

 

#2 It again all depends on what port job and pipes. PWK 28mm (30mm OKO's) if your going to be getting a play port. If you get a Dune port then I would run PWK33's. Drag port would run best with at least PWK 35's.

 

#3 A 4 mill crank will add midrange torque. It will make it pull harder. I would recomend one if you have the cash. Crank will run you about 400 from Jeff at FAST racing. Since your at 68mm bore you will need a set of 68mm bore yamaha blaster pistons. You run blaster pistons with a 4 mill long rod crank. You will also need a noss or cool head. Noss machine makes custom domes for 4 mill cranks. Talk with him about the domes.

 

#4. What port job depends on how you want your power delivery. MX port is going to be a bottom end port job. Trail port job is going to have great mid range. Dune port job is going to have a good midrange and rev higher in RPM's over a trail port. Dune port job gives up bottom end to gain top end, but still maintains a good midrange. Then you have Drag port it gives up midrange to gain Ultimate Top End. If it were me I would get a Dune Port job. It still has good midrange and it will allow your banshee to rev out a little more. If you want bottom end then sell your banshee and get a 4 stroke. :biggrin:

 

What builder. Jeff is a great guy to deal with. He is also a very buisy man. You could be with out your cylinders for a couple months waiting in line to have them ported.

 

FloTek, or Kevin Herr @ Herr Jugs Racing are good porters too. They also have a very quick turn around time. (couple of weeks). Usually the better known builder the longer the wait time and the more expensive the price.