PIPE choice FOR 144 big bores?

M

MW

Member

Nov 4, 2002

5

0

• Nov 18, 2002

• #1

Does the 144cc need a different pipe if the port timing is kept relatively the same? (mid-high rpm roadrace).
I suppose what I am asking is: should the pipe be chosen based just the port timing/rpm range or is the extra 19cc enuf to enter into the pipe choice equation?

 

steve125

LIFETIME SPONSOR

Oct 19, 2000

1,252

0

• Nov 19, 2002

• #2

Eric did the work on my last 2 144's one kaw and one yam. I spent alot of time on the dyno with both bikes and tried alot of pipes.  If you have a pipe that works for you stock or aftermarket it will work fine with the 144 kit. Most of the aftermarket pipes are close as far as the dyno shows, but they can feel way different on the track. The yz 144 made 38hp with an off the shelf FMF fatty. So to answer your question you don't need a special pipe for a 144 big bore.

 

K

KYHU

Member

Jun 12, 2001

84

0

• Nov 20, 2002

• #3

I guess that those 38hp are at the crankshaft. How many to the rear wheel ?


dave

 

steve125

LIFETIME SPONSOR

Oct 19, 2000

1,252

0

• Nov 20, 2002

• #4

The Dynojet measures rear wheel HP. So thats 38 at the rear wheel.

 

EricGorr

Super Power AssClown

Aug 24, 2000

708

1

• Nov 22, 2002

• #5

Heres the scoop on pipes, a big bore doesn't require any special pipe but a stroker crankshaft may, the difference is that there is a big change in the port timing with a stroker.
Generally speaking a pipe with a larger center section (FMF Fatty) should make better top end. A pipe with a narrow center section (Pro-Circuit) will have better transient throttle response. So the PC will tend to have an edge in whoops, short runs at jumps, and exiting turns.