New M50 airbox mod

[diamond_jim]

The center bolt was initially a 1/4" x 6" straight bolt which the triangular nut screwed on to hold the air filter cover on. In the back of the airbox I had drilled a hole a little smaller than 1/4" and screwed the bolt in it so it wold be snug. Then on the backside, where the bolt sticked out a 1/2", I added a washer, lock washer and nut. With that setup, I would unscrew the triangular nut to remove the chrome filter cover and filter.

With the carriage bolt, I reversed this. I ground down the round top of the bolt so that it would fit under the new chrome gas cap cover. I slid the carriage bolt through the original chrome cover and then put on a 1" rubber washer, 1" metal washer, lock washer and nut. I put the filter on, and then the cover on with the bolt passing through the back of the airbox just a bit. Another set of rubber and metal washers and nut snugged it up.

The chrome gas cap door cover is put on like you would on a truck, with 3M double sided automotive trim tape.

It doesn't show up real good in the pic but I inlaid blue paint in the middle circle that has the little squared part pointing to the rear. The chrome with blue inlay looks good with the chrome and blue of the bike.

[old new biker]

Thanks DJ,

BTW, I failed to mention that it looks great.
Nice Job.

Oldie

[diamond_jim]

[old new biker]

Thanks for the diagram DJ,

BTW, you may have mentioned it already, but I am curious how this setup compares with the stock setup regarding how far it sticks out to the left side.

With the John's Kits forwards my legs are a bit forward and my left knee hits the air box cover, causing me to, constantly, try to get my foot straight on the peg.

I also do not want to let go of another $255 for a new airbox. I am on the list for the DJ Drive mod, which I had not planned on, so saving money on an air box would be a good thing, as I still would like to get a PCIII soon as well.

I also think I am about ready to debaffle, but not quite sure yet. I will wait till after my inspection in a week or two at least.

[diamond_jim]

I've got john's forward controls as well. With the new airbox setup, my leg doesn't touch the air filter, even if I press the inside of my right knee against the gas tank. That's because the last few inches of the pointy rear part of the stock airbox and airbox cover is gone. Measuring at the maximum outward protrusion of the stock airbox, my setup is about 7/8" narrower.

When idling, you can hear just a little bit of the intake noise the bike is idling and you're standing on the right side of the bike. Sitting on the bike while idling, I don't really hear it. The stock airbox does a great job of cancelling out all of the intake noise in any direction.

[old new biker]

Originally Posted by diamond_jim

IThe stock airbox does a great job of cancelling out all of the intake noise in any direction.

It seems to cancel out breathing in air as well!!!!!!!!!!!!

[diamond_jim]

Originally Posted by old new biker

It seems to cancel out breathing in air as well!!!!!!!!!!!!

[diamond_jim]

I added a Cobra Fi2000R yesterday. I ran it first with the 1" restrictor plate in place. The Fi2KR didn't really make a difference except running smoother at highway speed. It couldn't make extra power cause of the restrictor plate. (At least we know that with any home made airbox mod, a 1" restrictor plate will keep the stock bike from running lean).

Then I removed the restrictor plate and tried it again. Definitely more power across the board but it was almost too much air when doing 90mph or more, even when increasing the 2nd and 3rd Fi settings. So, for the heck of it, I tried experimenting with different restrictor plate designs. I tried a 2" and then a 2.5" round opening. I tried 5 separate 1" holes. I tried it with an oblong opening first front to back then up and down. It may seem like a lot of work but the plates are made of plastic, cut easy and it takes maybe 5 min at the most to make a new one and swap it out.

The restrictor plate design below, along with Fi2KR settings of 3.5, 5 and 4.5, is hands down the best compared to other designs and settings I tried and as compared to no restrictor plate at all. I'm not sure why, but it provides the most even engine response and power regardless of speed. At highway speed, the faster I go, the more power it seems the bike has.

[diamond_jim]

This mod is no longer the "DJ airbox mod". It is now called the Typhoon mod.

[Kijak]

TYPHOON questions:

1) do you have to remove the whole assembly now to remove the cover (since there is no longer access to the triangle nut on top). I looked at it and I don't know how you would access the back otherwise.

2) I think i am going to do the same thing, but probably just use more of the plastic cut to fit under the 'gas cap' rather than the chrome. Any considerations?

Thanks J.

you GI#1

[diamond_jim]

Yes, I take the whole assembly off to replace the air filter. But the stock cover has three screws to remove the cover and I now have three screws to remove the cover. I've done it several times that I can remove the whole thing faster than I could remove the just the stock cover.

Kijak, you could do it like the pic below and either paint the cover or, what I'd recommend, is put a round piece of black vinyl (like used for making stripes on cars) over the chrome cover.

[Kijak]

Originally Posted by diamond_jim

Kijak, you could do it like the pic below Attachment 13541

Roger, but where did you get that chrome cover? I'm an idiot--and just starting with this--so thanks.

[Kijak]

OK, and last one...you think it would be a bad idea to do this before break-in is over?

[diamond_jim]

Originally Posted by Kijak

Roger, but where did you get that chrome cover? I'm an idiot--and just starting with this--so thanks.

It's one of these:


Streetflame

It's a chrome gas door cover for a ford truck. I got it at Autozone for $15.99.

Originally Posted by Kijak

OK, and last one...you think it would be a bad idea to do this before break-in is over?

If you're gonna have a dealer do the first service, then I'd wait until after that's done. I'm certain the airbox would be fine even during break in. I'm just recommending you wait just so the service guys won't give you any hassle. But you can make that call.

As for restrictor plates, I used the plastic from these kinds of heavy duty binders.


I used the kind that are solid plastic. The plastic is about 1.5mm thick and pretty sturdy. Don't use the ones that are like cardboard covered in plastic. But really any thin, sturdy piece of plastic can be used for the restrictor plate.

I found that a restrictor plate with a 1" hole worked great. I could feel a little more power without any evidence of it running lean. Now on mine, that 1" hole included the 1/4" bolt passing through the hole which takes up a little bit of room. When I tried a 1 1/2" hole, I found it was starting to run a little weak when I really got on it. That's because as I went faster and the rpms increased, the air/fuel ratio became increasingly lean. If you add a fuel processor you can then open up the restrictor plate.

[diamond_jim]

I was thinking about Profane's thread from the other day where he got caught in the rain and water got in his intake. I've gotten caught in one summer downpour. I was riding downtown when it suddenly hit. I rode abot 2 minutes in it and then pulled into an empty bay at an Express Oil Lube shop. I sat there and chatted with them for 10 minutes as the storm passed. I didn't have any problems. I figure if my bike sat in a hard rain like that for a while or I drove in a hard rain for several minutes, then I'd probably have problems. I think I'll make some kind of rain cover that I can throw on it if there is any worry for rain. I think Profane uses his bike for most if not all of his transp whereas I keep mine in a garage and ride when there's no rain.

[diamond_jim]

Originally Posted by diamond_jim

The restrictor plate design below, along with Fi2KR settings of 3.5, 5 and 4.5, is hands down the best compared to other designs and settings I tried and as compared to no restrictor plate at all. I'm not sure why, but it provides the most even engine response and power regardless of speed. At highway speed, the faster I go, the more power it seems the bike has.

Attachment 13395

I've since tweaked the Fi2K setting since then. I think I'm at 2, 5 and 5 now.

Anybody try any major airbox mods?

[Majestik]

Next on my agenda.

I'm looking to modify the air box position rather than the shape/design.

i like the upside down tear drop shape, so i know i will have to rip it apart and cut out the intake oval part and move it...

If i decide to do it, i will make sure to take pics of every step so it is easy for others to follow.

I'm also looking to see if i can come up with an easy to make round air box that will take a universal K&N filter (i saw a thread that someone did with a flange and i got an idea from that, not sure who posted it)...

The drawing board is ready and the pencils are sharpened, now i just need to squeeze is in my calendar

[Rockyrikoko]

Originally Posted by diamond_jim

I've since tweaked the Fi2K setting since then. I think I'm at 2, 5 and 5 now.

How would I translate that to my PCIII, or do they not even work like that?

Sorry, if that’s a dumb question. I just got the PCIII and hooked it up on my bike, but I have no idea how to use it. I just used one of the generic maps that come with it. The bike runs smoother now at least.

[diamond_jim]

I thought about this thread after posting something about rain on another thread. I rode in a darn good downpour this weekend. I had no problems with the airbox mod.

Here's an older pic of it for the newbies if you hadn't seen it yet.