Basic Airbox mods

markycee · Post by **markycee** » Fri May 13, 2011 1:04 pm

Stripped down my bike in order to fit a couple of Bazza's manual CCT's. Was just looking at the airbox. The standard box seems to take all it's air from quite a small opening at the front of the box. Has anyone experimented with simple mods (i.e drilling holes in the Top cover etc) Also, I noticed that in the plastic cover (below the front left hand side of the frame) there is a removeable rectangular piece of plastic approx 35mm x 75mm. Any ideas what it is there for. Is it worth removing to improve a little airflow?

If anyone got any thoughts on this would be interested to hear

tks

mark

bazza696 · Post by **bazza696** » Fri May 13, 2011 1:06 pm

benny has removed the snorkel from his air box, and Tony.mon has removed all the unneccessary bit from inside his air box, I think benny has had some noticable gain.

markycee · Post by **markycee** » Fri May 13, 2011 1:16 pm

Cheers Barry, got the bits today. is there any cap or something else that goes on top of the bolt (ie the bit that connects with the chain tensioner), or simply fit as is?

benny hedges · Post by **benny hedges** » Fri May 13, 2011 1:24 pm

mark the cct doesnt need that bung on the end like the oem ones.... the bolt doesnt touch the chain, just the guide

i removed that packer from the front plastics.... it's just an infill panel.
first i cut out the central divider from the snorkel at the front of the airbox but it was still running rich at the top end (im on 190 / 195 mains though) so i removed the snorkel altogether, fixed the needle setting and adjusted the mixture accordingly... (mixture screw setting was too weak probably cos there is no ram air effect at low speed just off tickover)

result - seat of the pants dyno - ace
i didnt see the point of putting it back on the dyno until i'd sorted the problems i knew about, as it would just waste expensive dyno time getting the jetting, needle setting & mixture spot on, but after months of tweaking, testing, fine tuning & more testing, it finally feels spot on, dead smooth transgression from idle to limiter, no flat spots or surging and a lovely intake howl when it comes on the cams

well worth experimenting but does take a lott of fiddling to get it right.
the storm engine is obviously very sensitive to carburation adjustments so unless you are prepared to have the carbs on & off dont mess!

tony has also noticed good results from completely gutting the airbox and i know chrisC has jacked up his tank (a'la sv650) to allow more airflow.

bazza696 · Post by **bazza696** » Fri May 13, 2011 1:36 pm

markycee wrote:Cheers Barry, got the bits today. is there any cap or something else that goes on top of the bolt (ie the bit that connects with the chain tensioner), or simply fit as is?

AS benny says this is not need, the metal cover only protects the rubber bung.

gilson · Post by **gilson** » Fri May 13, 2011 3:40 pm

There's another modification. Cut the airbox top just leaving the rim where the screws go through. This will then allow the airfilter (K&N) to be secured and screwed down without any restriction above it apart from the tank. this chap did it.

http://www.ablett.jp/bikes/vtr/air_box_lid.htm

Something to consider

benny hedges · Post by **benny hedges** » Fri May 13, 2011 5:48 pm

re the airbox lid mod, above or below depending how your page is set up lol, according to dyno andy at j33 dynocentre, who does all the dyno work for roger, they have done a few like that but it does require - in his words... "extensive mods to a race dynojet kit"
as in the needle taper needs altering, different pilots, mains everything...
i did ask what jets and needles they used but he wasnt keen on telling me and just said i should take it to roger lol.

what i intend to do with mine is use my spare airbox just for the adapters that screw onto the stacks, then cut the stacks off and fit a pair of bellmouth k&n's straight onto the carb, doing away with the airbox altogether.

wont be for a while tho as it's taken ages to get the fuelling right as it is!

incidentally, with raising the needles by 2 clips and setting the pilot screws 1/2 turn out, my fuel consumption is now more or less same as everyone elses lol, if not worse!
with 19L tank i now get approx 110 miles to the light with mixed riding.
*when i say mixed riding i mean proper mixing it lol

so if you want your bike to do more miles to the tank, drop the deedles or remove the shim from under them, back the mixture screw out a turn and keep it at small throttle openings!
it will run like a bag of sh1t like but you will get further on a tank.

i'd rather have it running spot on and drinking the stuff tbh.... it's still better than my car on fuel, plus if you are bothered about fuel economy on a bike you need to get a cg125.

tony.mon · Post by **tony.mon** » Fri May 13, 2011 7:24 pm

Watch this space, or more accurately my Engine Rebuild thread in Workshop, as i'm currently adding Ram Air and some other mods to the airbox, and will post up what has been done so far.

Slight setback last night when a killswitch backfire blew bits off the gutted airbox, I need to fix it up again but stronger glue needed, obviously!

One step forward, etc...

gilson · Post by **gilson** » Fri May 13, 2011 7:57 pm

Hi benny. That explains why Roger wasn't too enthusiastic about my
Bike which has this Mod. Mind you, it also has Moriwaki carbs, set up by Roger. It still needs some tweaking though.

benny hedges · Post by **benny hedges** » Sat May 14, 2011 12:29 am

is that the yellow stage 3 one???? im guessing it is?
i remember andy was on about it last time i was there.... said it's fkin awesome lol!

tony you're lucky you didnt suck bits into the motor mate, that wouldve been a right pisser

tony.mon · Post by **tony.mon** » Sat May 14, 2011 10:52 am

They're big bits, nothing will fit in the trumpets.
I thought of that.....

gilson · Post by **gilson** » Sat May 14, 2011 6:57 pm

benny hedges wrote:is that the yellow stage 3 one???? im guessing it is?
i remember andy was on about it last time i was there.... said it's fkin awesome lol!

tony you're lucky you didnt suck bits into the motor mate, that wouldve been a right pisser

I have a stage one tuned track bike which is fun but also the ST3 too. Roger is a saint, as most of us who have had dealing with, know.

I purchased it and even though It was running, I wanted to send it to Roger. I'll post the story when I get it back but suffice to say, after a lot of effort and head scratching, it's practically back to when it was first built, save for the starting parts which sap some power. There's one final problem that needs mamoru's help to sort and I'm hopeful to track it soon. Roger has just undergone his second knee operation on Friday and will be recovering for a couple of weeks.

I'm sure we all wish him well.

The ST3 has ram air air box.

tony.mon · Post by **tony.mon** » Sat May 14, 2011 7:39 pm

I was having a look at the possibilities for ram air this morning.

Connecting the triangular fairing holes down to the side of the engine is not difficult, but then routing it in through the frame and into the airbox itself is more tricky.

On the LH side the routing in through the frame isn't too bad, it will mean re-siting the front coil back and down a bit.
But the RH side has the throttle cables running right across the gap in the frame where you need to go. I could maybe re-route the throttle cables, but that would need longer cables- possible, though.

Once through the frame, the two pipes/tubes would need to meet in the area where the standard intake bends down at the front of the airbox, but that are can be easily sealed against the plastic heat shield below.
I'd like to open up the intake of the airbox a little as well, as the cross-sectional area doesn't seem to be as large as the combined areas of the intake trumpets, visually, anyway, I'll need to measure it and see.

I also looked at leaving the standard front intake alone and trying to lift the rear of the tank and fit an additional air flow into the rear of the airbox, above the filter, hopefully directing air into the rear intake trumpet.
The tank is pretty well flush with the top of the filter lid, and in order to get enough useful clearance it would need to be lifted 15mm or so at least.
That's not so difficult, a spacer under the rear tank mount is easy enough, and it doesn't look too odd lifted away from the frame like that.

And the routing from the fairing sides is easier too, with a smaller pipe each side- after all this is additional, and so doesn't have to carry the whole air flow, meaning that I could use a pair of smaller pipes down the sides of the carbs and connecting to the airbox lid at the rear above the rear trumpet, or just behind it.
Anything would help, I would have thought, although you wouldn't end up with a pressurised airbox this way, or very little, anyway.
Any excess air rammed in would just slightly pressurise the airbox and reduce the intake needs through the front normal position.

However I believe that the intake is marginal at peak revs, based on the fact that when you time the engine 180 degrees out it runs out of air at 6K or so, because the intake demands from each cylinder occur too close together.
So further apart intake pulses at double the revs would lead to a similar situation, and I think that we get close to that point with the standard configuration and setup.
Just my opinion, I haven't access to the equipment required to check this scientifically, and to be honest I'm not sure how you'd go about it- a dyno has trouble replicating a ram-air effect accurately.

So what do you think?
Contributions?
Opinions?

Anyone tried this?

alec · Post by **alec** » Sat May 14, 2011 7:48 pm

Tony i know nothing about what you said there but the only flaw i could see was if you lift the rear of the tank 15mm the front of the seat would be under it (without modding the seat) and would look odd.

tony.mon · Post by **tony.mon** » Sat May 14, 2011 7:52 pm

Good point, I can mod the bracket to deal with this.

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