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YUKI

air filter box - where to drill holes

12 posts in this topic

Need help on location of holes on the box. Can I drill the holes on the left removable fender (2006 XRL)?

ThanX

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Need help on location of holes on the box. Can I drill the holes on the left removable fender (2006 XRL)?

ThanX

.

Sure.

But make sure you either:

  • Know that the changes will make improvements
  • Simply don't care how it affects performance, but want the look anyhow

I'd read this first.

.

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Good info. Appreciate it. I am more concern with performance, rather than modeling on the trail. Can a good air filter close add the 5hp on mid range, or, it is nessasery to cut out the holes?

ThanX, Yuki

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.

[snip]...I'd read this first.

What I read there seemed to apply to motorcycles (streetbikes) that have tuned airboxes. I would never cut-up the airbox on a modern sportbike, for example. I doubt any of it applies to the venerable XRL's airbox. Actually, I'd be somewhat surprized if even a modern dirtbike uses tuned airbox technology in the same way that streetbikes use such technology. They seem to have airbox designs based more on packaging and compactness than resonance characteristics. I'm just speculating though...

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From what I've seen most people drill there holes toward the top front of the airbox. Keeping it towards the top keeps water out better and your leg will cover it from most debris while still letting her suck the air in. I'd say about 10 or so, 1/4" holes should do it. Most people use some type of prefilter(metal or fabric) underneath for added protection also.

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Good info. Appreciate it. I am more concern with performance, rather than modeling on the trail. Can a good air filter close add the 5hp on mid range, or, it is nessasery to cut out the holes?

ThanX, Yuki

I would put that hp number closer to 1 than 5. The L air intake is from the right side. After removing the factory snorkel there is a lip around the inlet. In my mind the air has to come under the side panel, bounce off the seat pan and then go through the opening. Most dirt only bike have a open top air box. That said, I removed most of the lip. Did it help? It's hard to say, but I didn't notice any negative effects.

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hmm ive been pondering making an air intake that comes out behind the seat, any thoughts on this?, if i do this ill be sure to post pics :crazy:

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hmm ive been pondering making an air intake that comes out behind the seat, any thoughts on this?, if i do this ill be sure to post pics :crazy:

This is pretty much where the air on a 650R originates. It gets sucked in on the left hand side of the seat and from the top of the airbox. Making one out the back of the seat won't really render a better snorkel function, if that's what you're after.

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On the L I only removed the snorkel then put some holes in the plastic ribs that support the seat. It looked pretty tight under there. This has worked great for me. Pleanty of air coming from the top, like stock just more of it (air).

I decided not to cut holes in the side panel for two reasons: didn't like the look and more important it exposes the air intake to more environmental threats: water, rain, dust, mud. I think under the seat is one of the most protected spots on the bike that's why the stock intake is there. They do make a little circular (3/4") foam type air inlet. If you do want panel holes I'd highly recommend using them. Still ugly :crazy:

I was thinking about putting all the battery box stuff in the air filter cavity after installing a "can" type foam filter directly on the carb. Was convinced otherwise because of the added exposure of the filter.

Just my opinion from what I've gathered over the years, I'm no expert.

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On the L I only removed the snorkel then put some holes in the plastic ribs that support the seat. It looked pretty tight under there. This has worked great for me. Pleanty of air coming from the top, like stock just more of it (air).

I decided not to cut holes in the side panel for two reasons: didn't like the look and more important it exposes the air intake to more environmental threats: water, rain, dust, mud. I think under the seat is one of the most protected spots on the bike that's why the stock intake is there. They do make a little circular (3/4") foam type air inlet. If you do want panel holes I'd highly recommend using them. Still ugly :crazy:

I was thinking about putting all the battery box stuff in the air filter cavity after installing a "can" type foam filter directly on the carb. Was convinced otherwise because of the added exposure of the filter.

Just my opinion from what I've gathered over the years, I'm no expert.

Much cleaner look if those snap-in fliters are installed on the right side of the airbox, under the side panel

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so....i'm a little confused.

does the motor need more air? or is the stock box (w/ aftermarket filter) without added holes ok??? Is there a noticable difference in power increase, etc?

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I think removing the snorkel is important as well as opening some holes in the seat supports. The snorkel is pretty restrictive and I think it is an added noise suppressor.

Actually I didn't run the bike with the snorkel on, it was part of the mods I did with the filter, carb and exhaust. It did run really lean before the mods.

And yes there is a very noticable difference in power with all the mods. From what I've read you need to do all the mods to make it all work. the fuel to air ratio is key to success and the only way to get in enough air to match the gas you add with the carb mods is to open 'er up.

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