I've got some cycle shack slip ons I'm about to install but I don't currently have enough $ for an air cleaner kit. Can I just drill some holes in my stock air cleaner backing plate to achieve a similar result? I'll have to take the cleaner off anyway to get to the mixture plug for the slow jet (which I'm going to replace with a 45) anyway.


Bone stock 2006 XL883.

I have heard of guys doing that.

It probably won't give the flow numbers that a high performance air cleaner will give, but it should be better than stock.

Last year at the Va. State HOG Rally, I had the dyno guy check Lily. He changed the pilot jet and put holes in the back plate (after asking/explaining how it would help). The jet and hole combination gave me about 5-7% hp increase and about the same for torgue. Still running the stock a/c though, plan to try the K&N when/if I can find one...

I kind of winced when the dyno guy dremel'd the back plate, but with the a/c cover on you can't see it. Hope the dealer tech's don't say anything about it... Maybe when I get the K&N I'll get a new back plate... maybe not...

I would like to find a back plate that moves the a/c forward some. Can't tuck my knee in tight on those cold rides... :laugh

Yes, I've done that. There's also a plastic deflector as part of the inside of the backer. This can go too. Make sure the air holes come on the out side of the filter element. You can an aftermarket filter element too, fairley cheap which will help.

Steve.

I bought a stock take-off A/C on ebay and took my dremel to it. Created long slots on the edges of the plastic ham can backing plate. Used 3/8" drill on ends and cut out in between. Kept some material to support the cover where the wide flat grooves occur on the backplate. Stuck a K&N filter in it and it works fantastic! Still have a good stock backing plate if I need to switch back for some reason. ;-)

I used a 1/2" drill bit on a drill press to expand my two holes. I held the backing by hand (probably not the smartest thing I've ever done), and moved it around to let the bit chew the plastic out. The holes are now 4 or 5 times bigger than they were, so less restriction=more flow. I didn't expect it to add a significant amount of power, but I was in your same boat being short of cash, so I improvised.

I'm happy with the results.

the stock FILTER sucks. You can run that filter without the supporting structure in the way and it will still NOT flow any better, drill till your hands fall off, until you do something about that crappy filter, you are doing nothing. It's the filter, more than the housing that is restrictive...

Agreed. I forgot to mention that I picked up a K&N off Ebay for dirt cheap. I totally agree that you'll see little performance gain using the stock filter and just drilling the backplate.

I'd still like to see a before and after Dyno report from a rubbermount bike with a stock replacement K&N filter in the stock Ham Can, with the stock backing plate either modified with holes or even not modified at all.

I'd still like to see a before and after Dyno report from a rubbermount bike with a stock replacement K&N filter in the stock Ham Can, with the stock backing plate either modified with holes or even not modified at all.

I'm not a big fan of dyno reports that come from sweep tests. However, if someone took the time to get a sustained run that would be interesting. I have a stock ham can that has fifteen 1/2 inch holes drilled in the backing plate and the flap is removed from the snorkel. I also use a K&N filter HD8834. I can tell you there is a major difference in the way the bike runs above 3,000 rpm. I also like the fact the waste air from the can flows outward to the right side of the juggs. I also got to keep the ram air by using the stock can....

Hi Kentucky,

Yes, I've read about your set up before and it intrigues me. I'm sure that it must make more power as you have said but I was wondering how much. It would be nice to see it measured. Even though your K&N filter is smaller than some aftermarket ones, I'd bet until it is loaded up good, it would make close to as much power as anything else with the mods that you have made to the backing plate, etc.,

I also like the fact the waste air from the can flows outward to the right side of the juggs. I also got to keep the ram air by using the stock can....


I'm thinking about doing this as well.

I have an 06 1200R and have no flap on the snorkel. Is this normal? Is the flap just on CA models?

Also won't drilling the holes reduce the ram-air effect by lowering the air pressure in the airbox?