'74 Penton/KTM 400 Jetting...

[adrian_goold]

Can somemone tell me what they are racing in their 38mm Bing near sea level.
Require Pilot size, needle jet, needle, and Main size.
Racing will be MX / Grass track.


Regards,
Adrian Goold
'73 175 running
'74 400 complete but in pieces
'78 250 running soon!
'80 250 project
'81 495 project
'00 250exc

[john durrill]

Adrian,
 here's  a base line from John P's article.
slide #1
needle #1
main jet # 170 to 180
needle jet # 285
pilot jet # 45
atomizer 40-404 ( the one that has a cutaway that faces the piston)
 air screw 1 to 1/2 out
 needel set to middle slot.
 oil to gas ratio and air filter will change this a bit.
 John D.

 

[Mike Lenz]

The main may be a little lean. Most of are running a 185.

 

[tlanders]

I am currently using in my '77 Mint 400 engine with the type II Bing carb:
Pilot = 50
Needle Jet = 3.20
4 ring needle with 3 grooves on leanest groove
Main = 185
Slide = I forget, fairly good size cutaway on the upstream side. I took a new slide I got from John Durrill and ground the cutaway to look like the worn out slide that was in it.

Teddy
and I'm still running a little rich. I will probably go back to the 3.18 needle jet