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homejob porting banshee?

11925 Views 6 Replies 0 Participants Last post by  cleartoy
is anyone experienced in protin cylinders on banshees or other bikes?
ive got the tools and the brains but i dont know the shape or the area exactly
to remove. thanks for any help!!!

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I used to have a Banshee, this was something I was thinking of too. Until, I raced a guy with a 250R that claimed he could blow away any piped Banshee. He had ported his 250R himself, shaved the head, bored .60 over, and of course he was piped. He was running race gas. I thought he was going to blow me away, wrong. My nephew on his STOCK 400ex beat him. We all run Sand Skate 2 tires.

Your port job is only as good as the guy that does it.

80 CJ7 with 4 inch lift, 33x12.50x15 Trail T/A
98 KX250
u just have to shape everthing so it flow nice ... u know on the intake side the bridge ?? just put a triangle shape on it u can also carve out the bump in the front where the reeds sits top&bottom on the exhust side u can carve out half of the material a good site to check out is he has all the info u might be lookin for

good luck !!

Porting is not really all that hard, but it does require extensive knowledge of two stroke theory and a very steady hand. Anyone can go in and clean out all the ports. Just go in and kind of just smooth everything over. All you will gain from this is just some throttle response and maybe alittle horse power. A true port job consists of changing the port timing, angles , and shapes. By raising the port heights you will effectively change where your power is, late early mid. The transfers pretty much control when the power will come on, it shift you from right ot left or vice versa. Port widths are also important. Wide is good, to an extent, you dont want too much fuel in the cylinder at certain times for certain applications. There are formulas which govern the demensions that the ports should be for particular applications. If you dont know how high and wide to go, then you will ruin cylinders more than likely. What seperated a good porter from one who just knows the numbers are the angles that he creates to direct the flow up annd throught hwe ports. This takkes lots of experience and reasearch. Macdizzy does have a very nice site. The talk about triangles and all that crap, is unknown to me. I have no idea what that is about. Dont go cutting on your cylinders if you dont know PRECISELY what to do. DO NOT listen to the people on this site who make it sound so easy and they dont have a clue. My sugestion to you is to read up on it, deecide what you want to do, and do stuff one step at a time. A set of cylinders take an experienced porter 12-18 hours to complete, if he does it right. Prepare yourself for a job. Never go into the job and just do it as you go, have a plan.

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Absolutely great advice Brandon....I was going to say something myself, but you beat me to it and said it better. People, don't go messing around too much with your cylinder(s) unless you are very experienced in knowing all the nuances of porting! A little cleanup and deburring is cool, but leave it to the experts and experienced to do it correctly!

Howard O. - Vista, CA
'00 Banshee
'87 CR500
the last 2 posts are most accurate!! go to the macdizzy site, if you can read this info and 100% comprehend it and still want to do your own port job you have way too much time on your hands. send your head and cylinder(s) to ERIC GORR 608-222-5761 a pro-porting service (see info on macdizzy) you will also realize after reading this info that most selfproclaimed porters dont have a clue as to what they are doing!!!

I would reccomend having a professional do it.

I got mine done by CBR Racing in Las Vegas. He charges $300. The ports look good, and the power increase was wild!


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