Removing the original restrictor, which main jet?

[KawaCor]

Dear forum members,

It is a little while ago when I bought my (almost) all original KLX650C. The only thing that is not originial is the exhaust, it now has a Supertrapp exhaust. The thing is, de bike still got his airbox restrictor on it, the big lid on the airbox which is limiting the air intake.
I would like to take it off to gain some PS, but I do need to change the main jet aswell. Otherwise the bike will run too lean.
My question is, which main jet do I need to fit? According to the manual, there is a 138 or 140 jet fitted at this moment.
Please let me know!

Kind regards,

Corné

[honney]

Hello and welcome.

i own a R-Model, so i can't help with your problem. perhaps you can try it with a lambda-test?

best regards