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8
Joined
12/9/2018
Location
GB
I have been reading about the air striker swap and I have a good understanding of the fact I need a short body carb and what to do with TPS and power jets.
I understand that the 36mm version (from older kx125s and KTM’s) might come with some benefits to bottom end power which is ideal for me because I will ride hare and hounds / enduro events. What I cannot find is how much the smaller bore carb will effect top end power.
Has anyone tried both the 36 and the 38 back to back? Or offer some advice on a reason for choosing one or the other?
I understand that the 36mm version (from older kx125s and KTM’s) might come with some benefits to bottom end power which is ideal for me because I will ride hare and hounds / enduro events. What I cannot find is how much the smaller bore carb will effect top end power.
Has anyone tried both the 36 and the 38 back to back? Or offer some advice on a reason for choosing one or the other?
Can you get hold of jetting specs from this for me, I just need a starting point?
I’m planning on putting my bike on the dyno to compare the mikuni to the pwk, I’ll post up the results afterwards.
The Shop
I tested all 3.
H4L: The mikuni 38 TMX made little more at peak (like .2hp) more than the PWK AS 38mm but was down on torque from ~4k-9k rpm. The Keihin makes way more torque (both 36 and 38mm) than the Mikuni and carburates more cleanly. The '02-'07's just seems to really like the 36mm AS's. I battled for years with the TMX on that generation of CR250's and tried every slide and nozzle known to man. Keihin = less headache and way more consistency, not to mention the increase of torque (about .5 lb-ft) up the whole front side.
Spoke to Chad Watts about both carbs last summer & he mentioned that when they were testing with RC's 02 CR2 HRC engine on the Dyno the Mikuni showed better gains mid-top vs. the Keihin PWK. They ended up going with the Mikuni TMX on the 02-03 CR's because of it.
He recommended the TMX with his engine package with jetting specs. He also does some mods to the TMX that help with performance.
Post a reply to: Cr250 05-07 36mm vs 38mm pwk air striker