As many builders i also have the problem of little space under the bonnet for the original airbox, i don't mind cutting a hole in the bonnet but i would like to reduce that to a minimum.

So what i would like to know is what the effect is if i change it for a Foam Filter unit, do i need to rejet the Carbs or do i need new needles etc etc.

Cheers,
Sebastian.

I'm sure I'll be corrected if I'm wrong, but I think if you fit an aftermarket air filter then you are introducing more air into you sytem, you then have to match that boost in air with a boost in fuel, which is often done by fitting an aftermarket Jetting kit (jets AND needles in my Blade case!)

hth
Steve

You cna modify the aribox to turn it through 180 degrees. Less sticks out through the bonnet them. This can help reduce noise and keeps the carbs out of the airflow. There maybe power gains to be had from a foam filter on rolling road but an exposed filter sticking through a bonnet may not be the best place to be to get a smooth flow of air into the carbs.

Allan

I have build my own airbox out off polyester.I first wanted to use a faom filter, but the disadantage of a foamfilter, is that it sucks itself full with petrol and leaves a nasty petrol smell when youre driving the car...
Rescued attachment CIMG1931.jpg

You should really get the carb’s jetted anyway since your exhaust system will be different from the bike. If you do use a foam filter then you should definitely get them jetted, when I turned up at the rolling road (with ZX9R + foam filter) my engine was running lean and hence the first power run gave me a corrected figure of only 103BHP. After jetting and tweaking, I came out with a corrected figure of 161BHP. I thought it was quick before hand, it felt like a rocket afterwards.

If you fit a foam filter it will be much louder but if you’re not concerned about that then go with whatever is most convenient. There is a lot of disagreement on which is the best solution but in my case the airbox would have been a nightmare to package and required a bloody ugly hole or bulge. I can say that if you go with the foam filter and get it set-up correctly you won’t be disappointed with the performance. It will be very fast, I guarantee it.

Marc

Sweet airbox Badding!

How you make it out of polyester?

Chris.

First I made a mould out of thin 0,5 mm Alu together with some wood.
Waxed the mould 4 times with releasewax
Then I applied a layer of topcoat with a paintbrush...waited 4 hours.
Then I applied layers off glassfibre with polyester resin.
Let it dry for 2 days and gently pull the polyster out of the mould.
Made an Alu frame on top to screw the Alu lid on.
The connection to the filter is a piece off Alu pipe, bought at a shop.
I think it´s a standard pipe for a kitchen to connect the fume huud.
Paint and finished...

My zx9r is fitted with a foam filter, and the carbs have been rejetted, when trying to set off with a bit of urgency, the engine bogs down a bit, also it struggles to pull through 4500-5000 revs, i was going to refit the original jets, but now i am un-sure, what would you fellas do.
Thanks Brad.

This is a good thread that might help. Was reading it again the day before last. Hope it helps a bit

Thanks mistergrumpy, i know mine has'nt been fitted with a dynojet kit, but has been rejetted, so from the link provided, it sounds like i need to block of this main air jet thingy, HHMMM. I will look into it.

Yep, sounds like it. I take it you took it to someone to do then and they just replaced the jets. Do you know what size you have in at the moment? I have all this to look forward to soon

Alas , no , i bought the engine, it had to sets of carbs, the set from the engine was slightly damaged, the other had the new jets fitted, ready for the car instalation, but what size they, i dont have a clue. The car goes like stink though, apart from said problems.

I believe the size should be etched on the jets and the standard is about 155 which is 1.55mm I think. Be interested to know what you have though if you do get a look.

I will be having a look, because i might be trying the original jets, just to see.