Air Box Mod

[f6rider]

 I was wondering of anyone modified the Airbox cover.
I removed the Baffle on the lid on my Rune with good results. Commments , experience?

[Bobbo]

I was wondering of anyone modified the Airbox cover.
I removed the Baffle on the lid on my Rune with good results. Commments , experience?

Some have drilled holes in it, but I think it lowered performance.
The airbox baffle does two things; it reduces intake noise, and creates a plenum to help the velocity stacks do their job.
What mods were you planning?

[f6rider]

remove the baffle plate in the lid.

[R J]

remove the baffle plate in the lid.

Leave it alone, as you will be looking for a new cover to get your performance back up.   Don't bother asking how I know this.

As Forrest Gump would say:
“That's all I have to say about that.”

[TearlessTom]

What RJ said, Leave it alone. the Valk is very picky when it comes to the intake.

[Patrick]

Some say they have modified it with good results,but, most have been unhappy.. I'd suggest leaving it alone.. Honda got it right..

[Blackduck]

Unless you are prepared to pull the carbs several times and play with jetting leave it be.
Even removing the foam pad from inside the cover will make it run lean for most throttle settings.
I am one of those who has opened the box up and have had some fun getting the jetting right.
It does perform better but it is a lot of trail and error. As to how much increased jetting is required I currently have 125's fitted but it is a little rich at full throttle (IE drag strip top end)
Will be dropping back to 122.5's for a trial. Runs great other than the very top end.
CHeers Steve

[GOOSE]

leave the lid alone.....it doesn't run good at all with this mod. 

[Blackduck]

http://photo.vrccservices.com/albums/userpics/10278/Air_Box.JPG
 It does run well but it takes some work to get right.
Cheers Steve

[98valk]

http://photo.vrccservices.com/albums/userpics/10278/Air_Box.JPG
 It does run well but it takes some work to get right.
Cheers Steve

+1 tunning and jetting.

for the other posts, its like any other engine. more air and fuel in more HP and TQ.

[Warlock]

I was wondering of anyone modified the Airbox cover.
I removed the Baffle on the lid on my Rune with good results. Commments , experience?

The best mod is add a 1/2" spacer under the front of the tanks. As others stated I would leave the air box along. JMO
David

[tank_post142]

1/2 spacer plus k&n filter 

[98valk]

see pictures of my airbox and intake tube mods.

http://www.valkyrieforum.com/bbs/index.php/topic,8248.0.html

[67blkbrd]

Unless you are prepared to pull the carbs several times and play with jetting leave it be.
Even removing the foam pad from inside the cover will make it run lean for most throttle settings.
I am one of those who has opened the box up and have had some fun getting the jetting right.
It does perform better but it is a lot of trail and error. As to how much increased jetting is required I currently have 125's fitted but it is a little rich at full throttle (IE drag strip top end)
Will be dropping back to 122.5's for a trial. Runs great other than the very top end.
CHeers Steve

Yes, yes I know I am dragging up the dead here. But I modified my air box lid today, nothing that I cant NASCAR fix until the unmolested one I ordered shows up if I cant jet the 3000-3500 (depending on gear) lean sputter putter out of it. I have read a bunch of threads on this topic and came to the conclusion that I will do as I have always done and mod it till I kill it or I am happy with it. From what I have read some people never found a solution to the lean issues with a modded lid, others have sputter putter down low but all is sweet up top and a couple others have figured it out. With 38 pilot jets and mixture turned out 2.5 - 3 turns it runs as well as it did up to 3000-3500 rpm then it has a serious lean condition. So I shimmed the needles and went from 100 to 105 mains, slightly better but far from good enough. So I will whip out my Mr.Fancy pants jet drill kit  and start working my way up until I get it within range to order a couple sets of jets that should get me a lot closer than a shot in the dark guess, probably wouldn't hurt to gets me some fancy adjustable needles too. I run a dial a jet on my KX500 dirt squirter and my carburated sleds but I don't think I really need them for the Valk, yet. In the end I feel that if a guy knows how to tune and is willing to do the work to completion that opening up the air box lid can be worth the effort. Do I know this for certian, no but I am sure enough that I have sailed that ship and I am going where it takes me.  I have no plans on messing with the tuned stacks but I will take full advantage of giving the engine all the air that the stock CFM carburetors can deliver. That is all for now, I'll report back when I have something to report, good or bad.

[Robert]

Unless you are prepared to pull the carbs several times and play with jetting leave it be.
Even removing the foam pad from inside the cover will make it run lean for most throttle settings.
I am one of those who has opened the box up and have had some fun getting the jetting right.
It does perform better but it is a lot of trail and error. As to how much increased jetting is required I currently have 125's fitted but it is a little rich at full throttle (IE drag strip top end)
Will be dropping back to 122.5's for a trial. Runs great other than the very top end.
CHeers Steve

Pretty much my experience also. I have 110s and need to go to 115 or 120 to complete the job with the baffle removed and spacer under the tank, K&N air filter. Still a bit lean, Am I happy I did it yes, top end much improved and full throttle really pulls.

[67blkbrd]

Unless you are prepared to pull the carbs several times and play with jetting leave it be.
Even removing the foam pad from inside the cover will make it run lean for most throttle settings.
I am one of those who has opened the box up and have had some fun getting the jetting right.
It does perform better but it is a lot of trail and error. As to how much increased jetting is required I currently have 125's fitted but it is a little rich at full throttle (IE drag strip top end)
Will be dropping back to 122.5's for a trial. Runs great other than the very top end.
CHeers Steve

Pretty much my experience also. I have 110s and need to go to 115 or 120 to complete the job with the baffle removed and spacer under the tank, K&N air filter. Still a bit lean, Am I happy I did it yes, top end much improved and full throttle really pulls.

Good to hear. I figure that as big a hole as there is in the fuel curve with the box opened up there has to be a significant gain to be had in the mid to peak power range.

[Blackduck]

Has been cleaned up a little since I took this, still running it and happy with it.
Jetting up around 127 now, still getting better than 30 MPG
Cheers Steve

[Robert]

Yes, yes I know I am dragging up the dead here. But I modified my air box lid today, nothing that I cant NASCAR fix until the unmolested one I ordered shows up if I cant jet the 3000-3500 (depending on gear) lean sputter putter out of it. I have read a bunch of threads on this topic and came to the conclusion that I will do as I have always done and mod it till I kill it or I am happy with it. From what I have read some people never found a solution to the lean issues with a modded lid, others have sputter putter down low but all is sweet up top and a couple others have figured it out. With 38 pilot jets and mixture turned out 2.5 - 3 turns it runs as well as it did up to 3000-3500 rpm then it has a serious lean condition. So I shimmed the needles and went from 100 to 105 mains, slightly better but far from good enough. So I will whip out my Mr.Fancy pants jet drill kit  and start working my way up until I get it within range to order a couple sets of jets that should get me a lot closer than a shot in the dark guess, probably wouldn't hurt to gets me some fancy adjustable needles too. I run a dial a jet on my KX500 dirt squirter and my carburated sleds but I don't think I really need them for the Valk, yet. In the end I feel that if a guy knows how to tune and is willing to do the work to completion that opening up the air box lid can be worth the effort. Do I know this for certian, no but I am sure enough that I have sailed that ship and I am going where it takes me.  I have no plans on messing with the tuned stacks but I will take full advantage of giving the engine all the air that the stock CFM carburetors can deliver. That is all for now, I'll report back when I have something to report, good or bad.

I have not done as serious a modification to my air box as Duck I took out the baffle but did not cut any extra holes. The other thing that I know is once you have 38 jets in the carbs and if you have to go almost to 3 turns out you probably have a problem in the carbs somewhere. Mid range while lacking sometimes on these stock jetted bikes were never really a big problem which is also why I say there may be carb problem. I have the 38 jets and had to adjust the idle mixture screws to about 1.75 turns out which is the what most with these jets have done. I had originally adjusted them to 2. to 2.5 turns out and then I bought my exhaust gas analyzer. When at Idle I hooked that baby up the mixture although ridable was to rich. What I have noticed since doing this was a smoother more consistent idle a better transition to mid range. Absolute better throttle response also. I believe you need to fix the problems with the carbs first then once a base is established rejet. I bought the stage 2 jet kit from Dyno jet and pretty much followed their instructions but the jet sizes needed to be determined. Hence playing with the 105,110, 115's. My mileage is over 30 mpg and at the highway speeds can go up. Another funny thing the consistency of the gas mileage is surprising over the stock jets. When going on long trips I would notice my mileage would vary now its fairly consistent even with head or tail winds or engine rpm range. The other thing is personal preference I would buy the jets not drill them. You may have the experience, knowledge and tools to do it but I like to be able to undo a step, like putting old jets back in when the new size may be too rich. They are not expensive and can be had from a number of sources. One other thing I need to mention, that I have a belly tank that has a fuel pump that delivers fuel to the carbs by pressure not gravity feed. The difference it makes is probably slight but I have never taken the time to measure the difference. I also run 2 fuel filters one more a strainer and one a ten micron filter. I do not want to be messing around these carbs unless its for interest not repair.

[67blkbrd]

I taped the air box back up last night so we could go for a ride today and with the box taped up and the 38 pilot jets I run the screws out 1.25 turns. Yesterday I had the screws turned out to try to cover the lean transition though I knew better. As for jet drilling, it is not the best way to go and I do have the proper tools but I will drill a set to get the tune in the ball park so I know for sure what jets I need to buy to dial in a proper tune. The ones I am in the process of drilling are the stock jets that came out of the bike. I am running the 105 mains now and as lean as it was with the box opened up during the transition to main jet metering I know it is at least 10 numbers so the jet drill I am starting with is the equivalent to a 115. I will get back on this project this week. Thanks again for your input on this.