Boxerworks.com

Flat boxes will have a history of effective modification, too.
typically regarding the size and shape of the "snorkle" tubes ...

I suggest you go over to the UKGS Airheads Forum and ask there, as Rob Farmer of that Parish actually measured flow with round and flat filters, and on the day he found the round filters flow better.

It seems that the tale of the flat filters flowing better is one of these pieces af accepted airhead wisdom that may be true on some bikes, but folks who have checked get completly different results on their bikes.

Roy Gavin wrote:I suggest you go over to the UKGS Airheads Forum and ask there, as Rob Farmer of that Parish actually measured flow with round and flat filters, and on the day he found the round filters flow better.

It seems that the tale of the flat filters flowing better is one of these pieces af accepted airhead wisdom that may be true on some bikes, but folks who have checked get completly different results on their bikes.

Could I trouble you for a link? I went to GSClubUK and couldn't find anything via some rudimentary searching.

Thanks.

The advantage of the flat filter boxes is not more flow but a tuned intake tract length for mid range torque.

It looks like this is the place but I couldnt find the info: http://ukgser.com/forums/

twist wrote:in the end I have to wonder if it's worth the time and expense to make that change. what are the benefits to cost? I do like the square box look but the round box isn't bad either. I want function over form. Spending money for the sake of something "new" doesn't make sense. If it works why change it? If there's an improvement to be had is it enough to justify money spent?!

Well, a square airbox set-up only brings about $25 on the used parts market but heres what you do...

Pull out your check book and see how much mulla you have. Then think about whether you'd rather spend it paying bills, turn in into a pile of $1.00 bills and toss it to strippers or spend it on your bike. In the end no ones gonna care but you.

I'm going to mod a square air box for my /6 because I have the parts on the shelf and I want to see it it'll work but even if I had to buy the stuff, it wouldn't be an expensive experiment, so why not? If I like the looks and/or theres some benefit, great. If I hate the way it looks or I discover some unforeseen problems? Well, theres always the option of reinstalling the early model parts and rolling on down the road.

I want to try my dry ice idea with the square air box. There must be a way to insert a piece of dry ice into the intake!

twist wrote:I want to try my dry ice idea with the square air box. There must be a way to insert a piece of dry ice into the intake!

Dry ice is carbon dioxide and would put the fire out.

I just want it to cool the air in the intake, didn't cross my mind that it's co2. another hair brained idea!

I found this...it's all I can find so far.

Rob Farmer from Advrider wrote:The only reason I fitted the early airbox on my PD was because the bike came with a mismatched engine, loads of dyno runs showed I had a problem with airflow at high rpm, the early airbox fixed this. When I get round to it with the exception of high comp pistons the engine will be put back to standard including the airbox. As a point of interest one of the guys over here spoke to HPN about a similar issue and was told the standard flat airbox doesn't have enough volume for the 40mm carbs, apparently if you make it 2cm deeper it makes a big difference to performance on 40mm carbed bikes. Morespeed also make a high volume replacement airbox and he's getting over 100 BHP out of his engines so there's something in it.

The thread has a FH "discussion"...typically back and forth. http://www.advrider.com/forums/showthre ... ht=airflow

Here's Moorespeeds site... http://www.moorespeed.co.uk/aircooled-b ... provements...big claims for torque and hp improvements.