port timing

[macgillivary]

hey sorry guys i did a search but didnt really come up with anything

im not planning on doing my porting just looking to understand it better

what is the banshees stock port timing? if anyone knows

also when work gets done to the transfers ive seen some numbers on macdizzys that are 130degrees, is that when the transfer is completly open from TDC? and where typically is material removed from transfers? do some builders just widen them and leave stock port timing? heard there was epoxys used to change things, is that for a faster flow into the cylinders?

sorry for all the questions just really curious, i understand the exhuast and intake, just dont really understand the transfers

thanks

[PassionRE]

Stock Banshee durations are exhaust 181.04 degrees and transfers 119.69 degrees. Durations are based on how many crank degrees in rotation from beginning of opening fo port to closing of the port. Widening or raising/or both of ports are the direction usually taken in mods except for where strokers on stock cylinders are concerned. Preference depends on flow requirements of the design where targeted HP is concerned, and in the style of power your looking for. Generally, low transfers make very peaky motors , taller tranfers make broader more torquey power, especially off the pipe. Exhaust area and transfer area must be mainained in balance for the type of power your looking for. Widening the transfers simply allows the transfers to operate more efficiently over the targeted spectrum of the power band your design calls for, and how much widening depends on exhaust area of the design needed to produce the style of power, and desired peak HP at a given RPM....Jim

Edited November 1, 2005 by PassionRE

[macgillivary]

thanks a ton jim, that cleared up alot of confusion with me, super helpful

with strokers do they lower the transfers also? is that whats different about porting for them?

 

when i get my port work done i wanna figure out my port timing just for my own knowledge, best way to do that with and i think the only way is a degree wheel right?

Edited November 2, 2005 by macgillivary

[cb67rs1]

You know i was going to say the same exact thing jim did but he beat me to it

[dawarriorman]

Stock Banshee durations are exhaust 181.04 degrees and transfers 119.69 degrees. Durations are based on how many crank degrees in rotation from beginning of opening fo port to closing of the port. Widening or raising/or both of ports are the direction usually taken in mods except for where strokers on stock cylinders are concerned. Preference depends on flow requirements of the design where targeted HP is concerned, and in the style of power your looking for. Generally, low transfers make very peaky motors , taller tranfers make broader more torquey power, especially off the pipe. Exhaust area and transfer area must be mainained in balance for the type of power your looking for. Widening the transfers simply allows the transfers to operate more efficiently over the targeted spectrum of the power band your design calls for, and how much widening depends on exhaust area of the design needed to produce the style of power, and desired peak HP at a given RPM....Jim

432148[/snapback]

I read it, I understand it, it makes perfect sense.

 

Yet somehow as the things I had wondered about were cleared up, I still end up more confused. I think I read somewhere on macdizzy's site that the more he learned about 2 stroke engines, the more he realized how much he didn't know. I now understand exactly what he meant.

Edited November 2, 2005 by dawarriorman