Pre-filter or not on EFI 990

[knobbyjoe]

To pre-filter or not on EFI 2008 990 Adventure

Yes I have search and been reading about replacing the snorkel with a pre-filter. But have not been able to figure out the consequences to the A/F mix with EFI. I want to keep the bike stock only trying to protected the engine and give the air box filter a chance.

The story: Just disassembled the bike for the first valve check at 15,000. There is too much dust and grit in the air box and a little bit inside the fuel injector side of the air filter. The filter was dirty and obviously past due to be replaced. I did notice a loss of pep while passing at speed.

The question: If I run the pre-filter will I have adverse performance or loss of gas mileage? Or is it just plug and play and won't even know I have a pre-filter installed?

Thanks Knowledgably gurus of the air/fuel mystical world

[DSM8]

Short answer is do it.

The benefits outweigh any disadvantage like loss of deep water crossings etc (like really deep).

I did it to mine and consider it a necessity if you do any sort of off road and dusty riding.

And no I didnt bother to remap afterwards either. But if you do it will be better from what I hear (I went to carbs).

[KTMADV]

I have a 2007 ktm 990 adventure with a home made filter and its not bad and bike runs great.

Look up ktm 990 pre filter on advrider. I have pictures.

[knobbyjoe]

KTMADV,
I want to, but "Home made Filter?" A link please. Are you saying you are the person that modified your pre-filter. Please the suspense. Tell me what you think. Some had questions about that and didn't get a final conclusion. Thanks KJ

[KTMADV]

What I meant to say was I used a Harley Davisdon pre filter and bolts with the back plate. I just cut out the air box and snorkle and made a little bottom plate and put it togeather.

I like it because you just use water to clean it or if you use oil on it you just use a K@N cleaner plus oil. If you use the oil it attracts more dust.. The filter does not move from the base plate because it has a lip on it. Here is a link of my pre filter very easy and cheap to do. Not bad on the dyno either

http://advrider.com/forums/showthread.php?t=837678

[knobbyjoe]

KTMADV,
I have read that several times. Looks good. Looks like I'd need to order some parts. When you get the time would you mind listing the parts and where to order?
Thanks KJ

[KTMADV]

I think the parts came off a 2000 Harley Davidson FLH Touring FLHPI police air breather with parts. I would have to take my filter off and go to my Harley Davidson shop to get the right part #s to post. You just have to make the little black plate that goes in the snorkel.


Its all very easy to do. It only took my three hours from start to finish to make plus a 12 pack of Newcastle beer.

[catalina38]

I did a few long rides (6000 miles) with identical 2010 990R's same exhaust, stock R map with the unifilter prefilter on one and the other with stock snorkle. They got nearly identical gas mileage, no noticeable difference in performance. The bike with the prefilter required it to be cleaned several times during those rides but kept the main filter cleaner longer. After the 6000 miles the more frequent maintenance became a PITA. More work overall for not much benefit. After this first hand experience I decided not to install one and he was going to remove it at the next filter replacement. YMMV.

[Hondo]

I replaced the snorkel with a Uni prefilter (wetted with No Toil) & it is wrapped with a filterskin.

No remap, runs great - 2011 990 Adventure.

[Apple Jam]

Originally Posted by catalina38;[URL="tel:20451516"

20451516[/URL]]I did a few long rides (6000 miles) with identical 2010 990R's same exhaust, stock R map with the unifilter prefilter on one and the other with stock snorkle. They got nearly identical gas mileage, no noticeable difference in performance. The bike with the prefilter required it to be cleaned several times during those rides but kept the main filter cleaner longer. After the 6000 miles the more frequent maintenance became a PITA. More work overall for not much benefit. After this first hand experience I decided not to install one and he was going to remove it at the next filter replacement. YMMV.

I put the UNI prefilter on 2 years ago. Stock filter still in place.
I had nothing to compare with,
but it did not seem faster/better, nor any mileage difference.
Intake sounded slightly noisier in a good way,
but the hassle factor of needing more cleaning, more often, is not really worth it.
I will either remove it or clean it, and not re-oil it.

[950TRANSALP]

get a bunch of " filter skins " and swap them out when dirty . 1 to 2k mi. .
this keeps the Uni clean .

[laramie LC4]

hahahah! nice avitair 950transalp, where ya get it? looks a lot like my old one.

back on topic, i just put a filter skin over the snorkle. not sure how much it is helping since i haven't checked it yet (only got a few 100 miles on it), but it's got to be better than nothing.

laramie

[950TRANSALP]

Did you oil the skin ?

if that was your graphic thanks !

[laramie LC4]

Originally Posted by 950TRANSALP

Did you oil the skin ?

if that was your graphic thanks !

nope. just stuck it over the top. i have always been told to leave the skin dry so that the dirt doesn't stick. anything that gets through will get trapped by the oil and foam, or in this case the paper.

laramie