Why would you run with no Air Filter ?

ucfmotorcycle1 · 08-01-2006, 3:17 PM

So I was doing the CMRA racing school at Hallett on friday. It was our second time on the track and I was on my 3rd lap when I started to brake for the turn and felt the bike not slowing like it should.
I clutched and heard the revs climb and bounce off the limiter. I twisted the throttle the opposite direction but the RPMS would not drop. So I pull over shut it down and wait for the crash truck.
We weren't going back out on the track so I just put the bike on the truck and decided to deal with it at home.
Well last night after extensive checking, adjusting and lubing of the throttle cables I decided to see what the throttle bodies were doing and when I open the air box the first thing I noticed is there is no filter. Then I noticed the rubber seal that goes under the filter was stuck in one of the throttle bodies holding all the butterfly valves open.

Mind you I just bought this bike 02 GSXR 600. So the previous owner either forgot to put the filter in (not likely) or He felt that there was significant performance gains from having an open air box.

Now I am new to racing but I feel that the possible problems associated with not running a filter would be far greater than any performance gains.

So do racers actually run without a filter? Or was this guy just weird?

By the way there were two new air filters in the box of extra parts that came with the bike. One of which is now back in the bike where it belongs.

08-01-2006, 3:22 PM

He most likely forgot to put it on when he was throwing it all back together I'd say. I've seen some weird stuff before like..... brake pads on backwards. Tell me that d00d wasn't in a hurry

abtech · 08-01-2006, 3:31 PM

I don't think you can find a national level superbike, GP bike or Moto GP bike with an air filter. I don't have any filter on my RC and none of my TZs came with them or had the means to mount one even if I wanted to.

Ever see a Funny Car, Top Fueler, ProStock or any wide-open class drag car with an air filter?

I also don't have anything in my airbox which could jam the butterflies . . .

sheepofblue · 08-01-2006, 3:37 PM

Paved sports are reasonably clean and durability is probably not severely impacted by the amount of dirt injested when compared to the stress from running at maximum performance.

I think I will leave mine in place though

ucfmotorcycle1 · 08-01-2006, 3:42 PM

Quote:

Originally Posted by abtech

Ever see a Funny Car, Top Fueler, ProStock or any wide-open class drag car with an air filter?

Were talking an amatuer club racer here. I would undertand if this was a professional race machine that was rebuild after every race anyway. But running an engine with no air filter will wear on engine. THe amount of wear depends on the quality of the air.

I had a filter fall of an RM80 I was messing around with in the dirt, I'm not sure how long the filter was off before the engine seized but it couldn't have been more than 30 minutes. Now granted this was a dirt road so there was a ton of sand in the air.

But the inside of that unfiltered air box on my GSXR sure had some sand in it too.

I don't know what level you run your bikes but unless you rebuild them often I would suggest putting on air filter on them and sacrifice the 3HP. In the long run you may actually be losing power with no filter when your rings are scratched up by all the sand that been going through the combustion chamber.

seamus · 08-01-2006, 3:45 PM

phobiaphobe · 08-01-2006, 3:54 PM

abtech · 08-01-2006, 4:14 PM

Quote:

Originally Posted by ucfmotorcycle1

Were talking an amatuer club racer here. I would undertand if this was a professional race machine that was rebuild after every race anyway. But running an engine with no air filter will wear on engine. THe amount of wear depends on the quality of the air.

I had a filter fall of an RM80 I was messing around with in the dirt, I'm not sure how long the filter was off before the engine seized but it couldn't have been more than 30 minutes. Now granted this was a dirt road so there was a ton of sand in the air.

But the inside of that unfiltered air box on my GSXR sure had some sand in it too.

I don't know what level you run your bikes but unless you rebuild them often I would suggest putting on air filter on them and sacrifice the 3HP. In the long run you may actually be losing power with no filter when your rings are scratched up by all the sand that been going through the combustion chamber.

I would defy you to find so much as a single piece of sand inside my 32 liter type 2 airbox. If my hand were small enough, I could reach through the ram air snorkel and stick my fingers directly into the throttle bodies.

A race bike requires vigorous maintenance and as such, I wouldn't have put my "new" bike onto the track without taking it down to the crankshaft and verifying that everything was in order. Obviously, you didn't make a very thorough inspection before trusting your life to someone else's work (or lack thereof).

BTW, it's more like 6 or 7 HP . . .

Nickelii · 08-01-2006, 4:21 PM

I never used a filter on my 748 and had no problems. Well, besides normal Ducati problems

ucfmotorcycle1 · 08-01-2006, 4:30 PM

Call me crazy but if I'm going to tear down a bike its because I know something is wrong with it or I'm parting it out.

As far as trusting my life with someone elses work well

... I'm not going to tear down every motorcycle I buy, every car I drive, and every plane I get into fearing that my life may be in danger. And I am sure most people wouldn't either. I did check the bike over before I rode it but I did not take anything apart. Nor will I with any future bike I buy.

Besides you can tear down a bike and rebuild it all you want and still have mechanical problems. You can do what you want but completely tearing down a bike to check it over is excessive.

Red Rider · 08-01-2006, 4:35 PM

sheepofblue · 08-01-2006, 4:35 PM

You just want an excuse to work on your bike Abtech

Nickelii · 08-01-2006, 4:36 PM

CBRVFR · 08-01-2006, 4:51 PM

ucf -

Abtech's bike is optimized. He probably researched which paint had the least air resistance. The pursuit of that kind of perfection requires a level of attention to detail that most people would consider "excessive," which is why some race bikes are really, really fast and others are less so.

It's the same thing with almost anything.. the last 5% of performance costs the most, and for some people, it isn't worth it. He's the kind of guy who gets all the performance available, regardless of cost in research, work, or money. And the bike moves along quite nicely - and sounds like God clearing His throat.

I run an air cleaner because I'm somewhat more likely to take a tour of the gravel trap than he is...

ucfmotorcycle1 · 08-01-2006, 5:06 PM

Good Point. I'll be sticking with the air filter too.

CBR929RE · 08-01-2006, 5:30 PM

the older I get, the more I learn (especially from Abtech's posts), the more I check things over. Understanding whats going on when the bike is running properly will can save your ass and save your wallet.

I'm on my third bike right now. When I bought it I rode it home and around town a little bit to get a feel for it and see whats going on with it. The next day it got an oil change (they said they just did one but it had a fram filter on there so all the more reason not to trust them), changed the air filter and checked the plugs. I didn't even realize the ones in there were the wrong ones (NGKs, but regular ones, not Iridium. realized it after I bought some Densos and looked at the tip). I just checked to make sure they looked good. They also claimed to have done the valve check, as soon as my friend got some time to help me, we checked them too.

No substitute for checking stuff yourself or having a trusted mechanic check it for you. I trust myself and myself alone with my safety.

seamus · 08-01-2006, 6:04 PM

Quote:

Originally Posted by ucfmotorcycle1

As far as trusting my life with someone elses work well

... I'm not going to tear down every motorcycle I buy, every car I drive, and every plane I get into fearing that my life may be in danger.

Not to Abtech's level of teardown, but every used car, motorcycle, go cart and lawnmower I've ever bought has at least received a tune up. Not just to replace filters and spark plugs that may or may not need replacing, but just getting to said filters and plugs allows me to get a grasp of the level of care the last person put into maintaining said motorized vehicle.

And knowing what I know about aircraft and aircraft mechanics, you might just want to do a walk-around of the next plane you get on.

luvtolean · 08-02-2006, 1:20 AM

Quote:

Originally Posted by ucfmotorcycle1

Call me crazy but if I'm going to tear down a bike its because I know something is wrong with it or I'm parting it out.

As far as trusting my life with someone elses work well

... I'm not going to tear down every motorcycle I buy, every car I drive, and every plane I get into fearing that my life may be in danger. And I am sure most people wouldn't either. I did check the bike over before I rode it but I did not take anything apart. Nor will I with any future bike I buy.

Besides you can tear down a bike and rebuild it all you want and still have mechanical problems. You can do what you want but completely tearing down a bike to check it over is excessive.

From another current thread:

Quote:

Originally Posted by Mojave954

PHUCK YOU it doesn't. That chit hurts. Got three pins that came out of my wirst that prove it sitting on my desk.

Axle nut fell off the WR, pinch bolts were loose (just got it that day from the dealer, less than 20 miles on it), right hand turn, disk binded in the caliper, pitched me down, broke wrist, 3 pins. (think it was just trying to show me who is boss right off that bat)

I won't say I tear them all the way down (though pretty close on most) but the only bike I didn't strip down, the MV, has messed up a couple of trackdays with mechanical issues. If you saw the bearings in most Japanese bikes, and the total lack of grease...you might change your mind too. I will admit, the price of grease in Japan must've come down, they seem to be using a bit more these days...(probably some study proved more grease would be cheaper by reducing warranty returns)

The two racebikes I've owned, were completely torn down before each season.

Just because you don't choose to make sure your stuff is tip top, doesn't mean it's right.

Custom900 · 08-02-2006, 3:27 AM

There are a few things I always check after buying anything mechanical. Any maintenance items are immediately looked after such as oil, filters, plugs, etc.

Repeater · 08-02-2006, 3:53 AM

I wouldn't have guessed some asshat forgot the filter either. friken some folks on here are rather holyer than ala, buda, and are headed for the ama (my ass).

Uh i gotta admit i missed the three nails in the tire when i bought my f4i. once i got it home i did inspect it on stands. that was the only thing i missed.

I did do my usuall overhaul after that.

Now does anyone have a rear shock for me or what?

Custom900 · 08-02-2006, 4:11 AM

Quote:

Originally Posted by Repeater

Uh i gotta admit i missed the three nails in the tire when i bought my f4i. once i got it home i did inspect it on stands. that was the only thing i missed.

So the previous owner used the bike for a peg board???

Repeater · 08-02-2006, 4:49 AM

the nails were in thier for at least a couple of thousand miles. they were 3 penny nails woren to a cent. one was at least 2" in

abtech · 08-02-2006, 12:35 PM

Just for the record, the title of this thread is : "Why would you run with no air filter ?".

I believe that question has been addressed. If you want to run an air filter, fine. It makes a lot of sense. I was pointing out that several "race machines" run without an air filter and it is not at all uncommon.

As I pointed out, the GP bikes don't even come with them, nor can they be fitted to run with air filters.

Yo