Air Box Cutting

[Daniel Wickers]

Been reading about cutting the top off my air filter box (currently fitted with K+N Filter)

What are the results/benefits if any? don't really want to start messing about with it if there is no real gain?

Cheers guys :-)

[Sofa King]

If you have stock jetting then I think this will do little more then make your bike run lean. the stock main jets on the Mikunis are 140's, and that's fine for the stock airbox and pipes. Just adding the K&N isn't enough to warrant a rejet, but opening up the stock airbox would be. if you have stock pipes I'd go with a 144, and if pipes are modified too I'd consider 150's. I have 150 jets on mine with K&N, open airbox and free flow cans. in fact its so much richer that until I cut open the airbox it would not run right. It was too rich. I actually prefer the engine to run a bit too rich to keep the EGT down and protect the valves/pistons/head.

[OOTV]

Definitely look into the jetting. The one one non-performance benefit is the sound. It does change it to lgown one growl, particularly when backing off the throttle. When I had my very first service done, I had the K&N, air box cut and a stage two jet kit installed (at least I think it was a stage two, this was back in 95 so mem is a little fuzzy) and the one thing that I noticed right away was the sound had changed. Of course once I started riding it I could feel a slight difference in power. I have since changed the rear sprocket 2 teeth lager and the of line performance is much better!

[Ritlee]

What if the bike is ie? would the computer compensate?

[catilover]

Originally Posted by Ritlee

What if the bike is ie? would the computer compensate?

i run pod filters on 6" runners on my 2002ie motor with open pipes in my 95 frame and it doesn't run lean at all, runs a little rich if anything (little puffs of black smoke when WOT from low rpm's) and i run a A/R gauge.

[ProfessorX]

When I had my 800SS tuned for the track, the tuner (J.D. Hord--hordpower.com) found only a 1 hp difference between stock and open airbox.

[lior_baruch]

Originally Posted by Sofa King

If you have stock jetting then I think this will do little more then make your bike run lean. the stock main jets on the Mikunis are 140's, and that's fine for the stock airbox and pipes. Just adding the K&N isn't enough to warrant a rejet, but opening up the stock airbox would be. if you have stock pipes I'd go with a 144, and if pipes are modified too I'd consider 150's. I have 150 jets on mine with K&N, open airbox and free flow cans. in fact its so much richer that until I cut open the airbox it would not run right. It was too rich. I actually prefer the engine to run a bit too rich to keep the EGT down and protect the valves/pistons/head.

I got a 1993 750SS, just got my K&N and cut mine.... glad to see your answer (and the thread's question, of course )

Anyone knows where to buy a 144 jets for the Mikuni BDST38?

Thanks,

Lior.

[stoshmonster]

Originally Posted by lior_baruch

Anyone knows where to buy a 144 jets for the Mikuni BDST38?

Maybe PJ Motorsports might have what you're looking for. Click me.>>>>>Buy Mikuni Jets @ PJMotorsports.com