"performance" air filter conversion?

[crayonjota]

Guys, I have a 1980 GS1000E and really the bike just rocks.

I just came back from a road trip and all went very well, apart from one small disagreement from law. Anyway, I was checking around the bike for stuff that may have loosened or fallen off (both rear indicators were very loose, but nothing else, and while smoking a fag admiring the dead bug guts on my headlight and visor,I figured that if a cold air induction works so well for my race car and van that it couldn't hurt the bike, and as a bonus the element would be long lasting and cleanable..

Has anyone pulled the stock airbox with its little paper filter and put one of these on? I have a friend with four little K&N filters going into each carb (Honda CB1000) and he says that it works well for him. I dont want this expense. All four carbs are balanced on my bike and the jetting seems right too, going by the colouring of the plugs. I know that this bike runs like a dog with no filter in place and before I put one on and risk a lean mix on my aged machine I was hoping for a little advice from a true expert (that will be anyone with a gs then)

Thanks in advance

CJ

 

[Dink]

The is a prefectly feasible mod, however be aware that changing the air fiter from stock will require re-jetting.
Dink

 

[Anonymous]

If you are going to use ram air with a freer flowing filter you will need more jetting than with no ram air. You don't want to lean out at 100+.

 

[lhanscom]

If you do ram air don't you need to pressurize your float bowls too?

 

[HiSPL]

If you do ram air don't you need to pressurize your float bowls too?

Yes.

 

[HiSPL]

This is an airtech built airbox for a 93 gixxer 750. You could design something similar for the GS.

 

[Anonymous]

Would...

Would...

connecting the carb vent hoses to your pressurized airbox work or would it screw up the fuel supply? Or is life not that simple?

 

[scotty]

If you do ram air don't you need to pressurize your float bowls too?

Yes.

Please explain what happens with the extra air velocity to necessitate modifying the float bowls??
Im having trouble visualizing it

 

[scotty]

I did a little browsing and unfortunately i didnt find info on pressurizing float bowls with the use of Ram air but at least i found an interesting article on ram air for snow mobiles and please pay particular note to some statements about tuning air boxes. OH BOY now i have to learn about tuning air boxes too :lol: :lol:

http://www.snowgoercanada.com/tech_ram_air.shtml

 

[Anonymous]

Please explain what happens with the extra air velocity to necessitate modifying the float bowls??

It's not the air velocity, it's the air pressure. The carbs work based on a pressure differential between the float bowl and the carb throat. When you pressurize the inlet (the carb throat side), you must also vent your float bowls to the higher pressure or the mixture will lean out. All sportbikes with ram air systems and carbs vent the float bowls to a point somewhere in the inlet ducting to balance things properly, but it is not an easy thing to set properly and is very sensitive to individual details of your ram air system.

Sorry to be the bearer of poor news. :?

Some good news, though. Ram air is mostly a marketing ploy, anyway. The gains to be had at reasonable (even semi-reasonable) street speeds are peanuts. The biggest gains in power come from supplying the engine with a constant flow of nice cool air, instead of high temp air that has been heated by the rad (in a liquid cooled bike) or engine. And the cold air intake mentioned in the beginning of this thread will do the same job without the mixture control issues introduced with a ram air system.

Mark

 

[crayonjota]

Ram air looks scary nasty for my naked bike... I tried the filter out though, with a bit more intake noise and a horrible idle/low rpm throttle response. Wide open throttle and overall speed were the same? In the end it seems that it all works better with the stock airbox!

Oh well...

CJ