Scooterotica

Darrell Taylor wrote:if a skinny pipe is used it wont matter as much but the fatter the pipe the requirement for correct case volume becomes greater

Presumably because of the volume of the pipe and the angle of the cones, providing the draw to bring the case gasses through? Is that right?

If you saw any of the LPC debates and wanted to add to those separately/resurrect an old thread so as to keep the topics separate and let this one focus on transfers etc, that would be great......be nice to see some of the old stuff that was left unresolved have more pieces of the jigsaw inserted.

drunkmunkey6969 wrote:

Darrell Taylor wrote:if a skinny pipe is used it wont matter as much but the fatter the pipe the requirement for correct case volume becomes greater

Presumably because of the volume of the pipe and the angle of the cones, providing the draw to bring the case gasses through? Is that right?

yes thats right fat pipes have a stronger pull/draw

which also means
on poor cylinder design skinny pipes can work as well as fat ones
good cyl designs get the best performance from a fat pipe

tea break over,back to porting some cylinders now

While you are on about pipes ...
Just a thought here may not be related to the topic...but....
Ts1 i ran jl3 (fat pipe) mpg not too bad at all, changed to franspeed race which i think is slimmer?
Anyhow mpg seems to have altered drastically and not for the better lol!
Is this just a conicidence , i think not and this is not at high revs either all the way through from tootling about on a run to a full throttle high mileage burn!
Is it the way the pipe works and draws the fuel through under compression changed here or have i got a worn needle or carb lol!!

i guessing then the franspeed is allowing more unburnt charge out of the exhaust port during the transfer cycle than the jl3

RICSPEED wrote:i guessing then the franspeed is allowing more unburnt charge out of the exhaust port during the transfer cycle than the jl3

Makes sense, design is for a narrower power band so the pulses needed to shove the unburnt charge back into the cylinder will occur
at higher revs and over a smaller percentage of the rev range....I think

Cheers for the reply guys ,

RUBBISH!.i have a wealth of experience with the most effective ports and i can definitively say that Cockburns vintage port in a brandy glass with 1 small ice cube is best. transfer ports should only be inbibed at the airport bar during breaks in longhaul flights and will invariably be expensive affairs. as for dremeling away at perfectly good Lammy casings i know f@@k all about that except that a cigar and smoking jacket isnt usually needed when grinding metal.

Wot port timings is it being run on? the JL3 will run better on lower port timings, and the Fran speed race on higher port timings.

Timings :wtf:
Runs a 60mm crank , 0.5mm packer/gasket no head gasket , low comp head af jobby reprofiled by JB, carbon petals on a lth manifold and vhsh30mm.
Nice engine to ride , sure i met you at Al's when i came to dyno it (pre 60mm crank though) and was 21hp then , so with the franspeed race certainly feels a lot faster but sucks the juice ?
No porting at all on cases or barrel , although that may change after reading Darrels and smiffys work re extra boost port with no welding , anyone want to use my engine as a project to see a before and after type thing with these tuning measures put into practice to find out any real gains.......

alcoholic maniacs sc wrote:RUBBISH!.i have a wealth of experience with the most effective ports and i can definitively say that Cockburns vintage port in a brandy glass with 1 small ice cube is best. transfer ports should only be inbibed at the airport bar during breaks in longhaul flights and will invariably be expensive affairs. as for dremeling away at perfectly good Lammy casings i know f@@k all about that except that a cigar and smoking jacket isnt usually needed when grinding metal.

You'll get gout!!