Custom air filters

[Amz]

I have a 1996 Honda Degree XL250 trail bike import for which I can't get an air filter for in this country. It's an flat L shaped plastic frame with wavy orange paper in it. I am quite capable of fabricating up something but don't really know what the best way to go about it is. Can i just fit a cone type filter in the air box or do I have to consider how it will effect the air flow and re jetting and all that which I don't want to go into?

[vifferman]

Does the frame have a mesh support under the filter? If so, just cut the filter out around the edges. Buy some open-cell filter foam (or plastic foam about 20mm thick), cut it slightly larger than the frame with a sharp knife or scissors, and glue it in with silicone or hot-melt glue. Oil it up with some airfilter oil (or even engine oil will do), and stick it back in the bike.
I've done a few bikes like this now (VF500, VTR1000 and the VFR800).
You shouldn't need to adjust the jetting, it will only cost a few shekeldollars, and you can wash and re-oil it when it gets grubby.

[Amz]

Cheers for that. Yes it does have a mesh on the airbox so I just might have to do that then. Thanks.

[Pixie]

Does the frame have a mesh support under the filter? If so, just cut the filter out around the edges. Buy some open-cell filter foam (or plastic foam about 20mm thick), cut it slightly larger than the frame with a sharp knife or scissors, and glue it in with silicone or hot-melt glue. Oil it up with some airfilter oil (or even engine oil will do), and stick it back in the bike.
I've done a few bikes like this now (VF500, VTR1000 and the VFR800).
You shouldn't need to adjust the jetting, it will only cost a few shekeldollars, and you can wash and re-oil it when it gets grubby.

You will need the correct type of foam.There are 2 types of polyurethane foam.One type is degraded by water but resists degradation by oil this is the type you want.the other is ok with water but oil rots it.
Pararubber can get you the right type if you make sure they know what you want.
Or call Dunlop Foam and get the correct product name: http://www.vita.co.nz/mainmenu71/page39/Dunlop+Foam+Fibre.html

I've just found out it is called Reticulated foam and may no long be available from Vita.

[vifferman]

Really?
I did not know that.
The foam I used was sold under the Unifilter brand, at Motomail. It must be resistant to everything, as it has oil in it, and to clean it I use filter cleaner followed by a thorough rinsing with water, followed by drying out and more oil.