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Modding the airbox on a '97 SRAD 750...

5K views 19 replies 10 participants last post by  kevinc 
#1 · (Edited)
If you don't have a 96 or 97 Srad 750, or know alot about this,
Please move along, these are not the droids you're looking for.

And yes, I've read all the old posts on the 'search'.
For instance- one of the older posts mentions a 'flapper valve', removing it, plugging the vacuum line, etc.
Well my stock 97 SRAD750 has no flapper valve, NO electrical connections, etc.
It does Not have a rectangular airflow opening either.

Here is the pick of it without the air cleaner in



It is obvious to me that the sleeve looking opening prevents water from the Ram air going to the carbs,
There is a drain in the bottom of the air intake, previous owners have put electrical tape on mine?

The underside, no wires/electrical anywhere, no flapper valve



If I take out the 'sleeve' with a dremel tool, it negates the water intake prevention some, but I rarely ride in the rain anyways. The mod removes all that and opens up the intake area some.
Then people posted that the bike didn't run right after doing it.

The total surface are of that oval is MUCH smaller than the total of the intakes of the 4 x 39mm carbs.

Have you done this to a carbed Srad 750? What were your results?

TIA,
Todd
 
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#2 ·
Todd,

Flapper valves etc are generally for fuel injected bikes.
Your air box is part of a tuned ram air system on a carburetted bike . Sure, you can shoot in the dark, open it up and let in a little more air, and then fiddle with your jetting etc. What are you really hoping to gain?

If you scroll down Air Tech's page, you will see fiberglass air boxes for your bike, that are fully open on the inside, lots of volume...and they were intended for built engines with flat slides, lots of tuning was involved.
SUZUKI GSXR 750 1996-99, GSXR750 fairing, fairings, tail, seat, front fender, rear hugger, upper, lower, bellypan, fuel tank, undertail

If you are looking for better performance, I would first ensure that your bike is in optimum condition. Basic tune up stuff and then check valve clearances, carb synch, compression test, leak down etc.

Cheers,
Scott
 
#3 ·
Thanks Scott,

I dynoed it yesterday, and the a/f never hit 13.
at lower R's, 2-5K it was 11 or below.
At best at the higher R's, it got up to 12.75.

I checked, the stock air cleaner wasn't really dirty at all.
Does the K&N really flow that much better?

by at least adding some holes in the bottom of the area inside the filter element, lile 2 x 3/4 " holes- may help it out some.
 
#4 ·
No later model carbbed 600/750 people out there that have done this mod?

Let's bump it up for a few days
 
#5 ·
Oh well,
I"m drilling a few 3/4" holes in the plastic inside the area that'll get filtered.
I really don't expect much if any change, we'll see.
 
#6 ·
You don't think you'll need to re-check the AFR and re-jet accordingly after drilling several large 3/4" holes into the airbox???
 
#8 ·
I'm about to, and unless a the stock air box with a fairly new filter is that restrictive, then no,
I don't expect to have to re-jet, etc.
ON the one and probably only dyno I did, it was running really rich.

I hope it was accurate, etc.
 
#10 ·
Oh, I'm sorry. I can see how my post and thread seemed to think that
I did perceive a restrictive airbox problem.
I only hoped that perhaps my 4 month old Gsxr had what could have been a really dirty air cleaner based on the a/f results of my dyno.
It wasn't the case, and wawsw actually quite clean- like the previous owner said it had been recently changed.
*( Usally, air cleaners on my truck/SUV/and/or lawnmower/snowblower has small dirt particles come out when tapped sideways onto a cement driveway- my Gsxr had nothing visable at all some out, and the color is still off white.)

I just thought while I was in there :)surprise:), I thought I'd have a go at modding it some.

Here is the final result before I put'er back together a bit ago:





I didn't get as radical as the older posts on air box mods have been,
and the holes are 1/2".


I got everything put back on/in, and cranked her up.
Fired right over. I let it warm up on the rear work until it got to about 145F.

Sounded great in the garage with the door open.
I'd like to think it seemed slightly even more responsive in the lower R's in neutral.

I think I'm taking it to the Drag strip near my home this saturday.
Me and my friends 'Life on 2's Famalia'

My bike's so old, over 26K miles, I'll be happy if I can run somewhere in the 11's.
 
#19 ·
I actually have a 96 SRAD and when I bought it (second hand) the entire area had been cut out. I managed to jerry rig it back to something that looked normal. Turned out I had other issues that have now been rectified. Mine runs fine but does appear to run a little on the rich side also. I have a sneaking suspicion that fuel consumption MAY have increased marginally after I re-restricted the air box airflow. Did you come to any definite conclusions? Mine had been up jetted and has a Yoshi RS-3 end can. Thinking about opening it back up. The bike ALWAYS has had massive high rev performance but again I suspect that just MAYBE I have lost just a tad above 10000 since re restricting the airbox. This again is hard to tell because the previous issues had robbed some bottom and midrange (5-7500 ish) so it would be natural to think that the top end seems les of a rush when the midrange has definitely improved. It now just seems to get stronger in a more linear fashion than before instead of like nutso at 10500. Now the issues seem to be dusted may try with the cut out in and out and try to a feel without getting too anal about a bike which for all is said runs pretty damn well.
 
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