Enlarged Airbox (and other Airbox Mods) for Carbed Monster

[Speeddog]

<bookmark>

 

[ducpainter]

<bookmark>

 

I'm with you...

[koko64]

I've emailed you some photos and jetting info. Cutting down and porting the rubber velocity stacks is a pain in the arse and raising the air filter less so. I think both are important as the whole might be more than the sum of the parts.

As I said to Brad the other day, it's mitigatng a design characteristic with these motors, the inlet tracts could be shorter and the airbox bigger.

I'm looking for someone to make a nice carbon airbox lid with integral filter. Then I can give up cuttng and gooping. I'm not that crafty.

[ducpainter]

I've emailed you some photos and jetting info. Cutting down and porting the rubber velocity stacks is a pain in the arse and raising the air filter less so. I think both are important as the whole might be more than the sum of the parts.

As I said to Brad the other day, it's mitigatng a design characteristic with these motors, the inlet tracts could be shorter and the airbox bigger.

I'm looking for someone to make a nice carbon airbox lid with integral filter. Then I can give up cuttng and gooping. I'm not that crafty.

Got them...thanks.

Hmmm...c/f lid?

[koko64]

A mate of mine knows someone who used to make them. Got to convince the guy to start making them. I don't even know what they look like yet. Using the stock parts only costs a couple of hours time and a tube of goop, but "porting" the stacks takes patience and concentration.

[koko64]

Visited Brad today and showed him a finished enlarged airbox (for a customer) and swapped him some "ported" stacks to test. We discussed ways of acheiving a better airbox, etc (really better done over a beer than me distracting him at work)

Brad will test the "ported" stacks against stockers on his 750 engined M600. I should also have an enlarged airbox lid for him when it's time to test. So there should be some answers for you 750 guys. The motors have different power characteristics and issues so it will be interesting to see how the mods apply to that motor.

[Howley]

Curious as to why cutting the stacks is difficult. What am I missing?

[Raux]

Curious as to why cutting the stacks is difficult. What am I missing?

just a thought, but since the stock match up and it's a funnel, cutting it would cause a mismatch. Whereas starting with a different size funnel and cutting it down to match would make sense?

[koko64]

If you check out the pictures on page 1,  you can see that it is possible get a good radius and fit.

So you get a sharp knife, cut them down and then carefully scrape or whittle away material, then sand down or scrape the angles to get a nice radius. Take off too much material and they're ruined. Got a price for new stacks at the dealer  $50 a piece! Used ones half that.

It really is porting in a sense as you have to carve and shape a good radius to promote airflow. It is a difficult material to work with and requires patience.

Cutting the stacks down to where they enter and join the airbox works well. They end up about 18mm shorter and the widest part of the funnel is 5mm greater in diameter than when in stock configuration.

Hard to explain, but when you have a go at doing it you know very quickly!

[ducatiz]

If you check out the pictures on page 1,  you can see that it is possible get a good radius and fit.

So you get a sharp knife, cut them down and then carefully scrape or whittle away material, then sand down or scrape the angles to get a nice radius. Take off too much material and they're ruined. Got a price for new stacks at the dealer  $50 a piece! Used ones half that.

It really is porting in a sense as you have to carve and shape a good radius to promote airflow. It is a difficult material to work with and requires patience.

Cutting the stacks down to where they enter and join the airbox works well. They end up about 18mm shorter and the widest part of the funnel is 5mm greater in diameter than when in stock configuration.

Hard to explain, but when you have a go at doing it you know very quickly!

what about using a dremel and a cutting stone to whittle it down?

[koko64]

Worth a try for sure, maybe with a fine sand mop to finish. But thats after cutting the extension off with a scissors/knife.
I was cautious using static tools because it was like tattooing, the medium wasn't very firm and you can't clamp it. Its holding it in one hand and the tool in the other. I found foam sand pads great to get the tactile feedback and not go too far, to avoid ruining it.

Brad suggested freezing the stacks, that could help before using the dremel. I put mine in hot water first and them cut them down with sharp scissors. Then peeled the first angle of the radius with a sharp filleting knife, then some good ol' fashioned whittlin', then finished by sanding for the "porting" .

I reckon at least half an hour to an hour on each stack for the last set, but the first set were done in half that time and looked better. The rubber carved real easy.

Strangely, each pair of stacks has been different to work with, maybe due to heat cycles, age, rubber batch, etc.

Edit: I am porting another pair now and are using different sand paper to finish it off. It is coming along quite easily now that I'm game enough to use some heavier sand paper before finishing off with a fine foam backed sand paper.

[koko64]

The airbox mods definately flow more air.

With the extra airflow, I also needed to increase the slow fuel jets another step with 55s. I needed to open the slow air screws a quarter of a turn to 1 3/4. I have the IMS at 1/2 a turn. Really needed a richer needle root diameter, but slow jets are cheap. Low speed tuning is often best done with test riding than on a dyno. It's important to test for ridability and feel at small throttle openings rather than theoretically correct numbers on the dyno.

With a bit of juggling on the jetting it idles well, has fierce pick up and is smooth at backstreet and cruising speeds.

Edit: (The bike has significant modifications including a light flywheel and portng of the inlet tract so don't take the following statement as being just due to a bigger airbox).

Wheelies. Second or third gear. I don't try them in first gear!

[koko64]

Speaking of airboxes, take a look at the EVR carbon airboxes at Motowheels.
Very impressive. Alas, nothing for the older desmodues.

[ducpainter]

Speaking of airboxes, take a look at the EVR carbon airboxes at Motowheels.
Very impressive. Alas, nothing for the older desmodues.

I'm not aware of anything EVR for a 2V.

[koko64]

There is an impressive looking large airbox with carbon velocity stacks for the Hypermotard 1100. It appears to have a substantially increased volume. I cant figure out what type of filter it uses or where it's located. Not even sure where the air intake is.
Its in the engine intake section. $1500!