Suzuki GS400E jetting

[M.A. Jacques129]

Hi, I just bought a set of MAC exhaust for my GS400E 1983 and I'm jetted 120 main, stock. Anyone jetted his 400 with mod exhaust and more opened air-box before? I don't want to try 5-6 jetting setup before picking the right one.. I was thinking to put 140 main but it is actually pretty lean, the spark plugs are white, I don't know if I have to put bigger jets than 140..

[pete]

I have K&N pods in my '82 450E with a free flowing 2 into 1 custom pipe.

I'm not sure how the size of my jets compare with the '83 models (different carbs) but stock mains are 117.5 and I'm currently running 137.5 however I think I'm still too lean so will be trying 142.5 next.

I also have my needle lifted as high as it will go so it is as rich as it will get.

I still have the stock pilot jets.

[M.A. Jacques129]

Thanks for the info, i'll try 145 if you say you're too lean at 137.5!

[pete]

I've just gone up in mains two sizes at a time although my first guess of 8 sizes up turned out to be a little lean I feel.

I won't really know for sure until I try the next size up and/or get some plug chops done...