Bimota Forum

[2bims]

Anyone out there fitted K&N Mesh/cone air filters to standard Mikuni 38mm carbs? As on DB2/DB4?

If so is there any jetting changes needed simply coz it can breath better?

Finally got round to changing the air filter on the DB4 and cleaning out the airbox....bit of a faff to be frank...hence thinking of ditching the air box and going the K&N route...seems quite strangled with the existing set up and the restricted opening at the front of the boz and its "baffle plate" to supposedly keep crud out....















And yes....better to fit Keihin or Mikuni flatslides etc etc , Vort...before you suggest...but trying to keep it fairly standard and just improve the breathing....

All other feeds, crnakcase breather, overflow pipes etc are already disconnected from the exiting 2-part airbox...just seems an overcomplicated set up, and not just for removal and cleaning/checking

[vort28]

Guess it would be a dyno-jet kit at worst and the filters , and lets face it these days they must give the dyno-jet kits away with 2 Kellog's cornflake tokens
Not much call for proper jets anymore !!
When I was a lad !!!???

[SpikeC]

From all of my reading numerous posts on numerous forums, the pod filters will require rejetting and will cost you a hp or two. You are better off modifying your air box to improve breathing. The engine needs a plenum chamber to draw from to cause the least restriction in incoming air. Something along the lines of replacing the air box lid with filter medium as I did on my DB5R is one possibility, or making a larger opening in the box. I am not familiar with the geometry of your air box, so you would have to be a bit creative as far as what exaxctally you need to to do, but that is the general direction.

P.S., the pods also make the intake noise very loud!
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Spike C.
Portland, Oregon, USA
2008 Bimota DB5R
1965 Triumph T100SC

[brian]

Did you end up doing anything here Steve?
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'99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851

[2bims]

Nah...not in the end Brian no.....general consensus was that it wasnt a good idea to increase breathing capacity unless rejetting also...so I cut to shape and fitted a new piece of Ram air Filter material and put back together....did seem to be a fair bit of oiley crud in the filter box that I cleaned out...which I thought was strange as theres no Crank breather tube filtering into the airbox on my bike since I fitted an aftermarket crankcase breather filter....Maybe I had just never checked/cleaned the airbox out in my ownership...gulp...

[brian]

Ok. I thought about putting a dynojet kit in mine a while ago but haven't done anything about it. Just been enjoying riding the db4, nice to have it running sweet finally
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'99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851

[2bims]

Yeh.....I try to stick to the old addage of "If it aint broke....dont fix it"....and Db4 has probably been the best runner in the 4 years I've had it compared to the other bims....has never refused to start, blown a bulb or had issues....so clean, use, maintain.....repeat.......

[Evilchicken0]

If you got a flat panel K+N the right size you could cut it to shape and finish it with silicon. That should give you a better and more easily cleaned / oiler filter and improve the breathing too.
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Don't read everything you believe