1979 GS 400 Bing54 carb swap

[GeorgeBressler]

I would like to covert this carb to 250 spec unless someone has a good Bing 54 set up for 250 that they would like to sell.
I am looking for jet sizes, needle clip position, air settings. etc
Thank you & see you guys at York Pa in a couple weeks
George Bressler
New Cumberland, PA
717 215 8154

[454MRW]

George, I have a 79 service bulletin with jetting info, but am in California at the moment, and can check on Friday. There is actually very little difference between the 250 & 400 jetting.

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Penton
1976 MC5 400
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM's
1976-78 125-400 RM's
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R

[GeorgeBressler]

Thank you Mike- looking fwd to talking with you when you get back- George B

[454MRW]

It looks like the 400 has a 185 main jet versus a 175 main jet for the 250, both use a 282 needle jet and a 4K2 needle and clip is in the middle position. The idle jet is 45-50 on the 250 and 50 on the 400, the vaporizer is a number 2 on the 250 and a number 4 on the 400. The air screw is 1 and 1/2 turns out on both, and both GS-6 and MC5 models used 38 mm Bings on 250 and 400.

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Penton
1976 MC5 400
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM's
1976-78 125-400 RM's
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R