Looking for a good air filter

i dont even have room for the stock airfilter,so im making one out of a sippy cup lid and some other plastic plus my stock filter parts.
 
Down_South said:
Nope. It works like a charm and it's cost effective.
Click to expand...

Do you know how abrasive scotch bright fibers will be in your engine? I don't have any problem with low cost filters, I just don't think that's a good choice of material.
 
Its green plastic fibers that are rinsed with water and then dried. Put a vacuum on it and see what you get. I've had no trouble.
 
Last edited:
hey i went to the local autozone and bought a fuel filter and drilled two for the screws & 1for the choke and it costed me about $4.00 and then sealed up the two spots with sealent
 
I built a new intake to take advantage of this air cleaner and velocity stack that came with my pocket bike pipe. I had to drill the back side of the velocity stack with a 3/8" bit about 1/4" deep to allow clearance for the nut on the stock choke. There's plenty of meat to do this without even coming close to going thru. Other than that it was a bolt on. It's an all steel intake, the tubing was from a junked import car engine. I think it was a heater hose tube. It fit the carb almost perfect. I had to sand the tip at the carb some to get it to seat into the carb all the way. The thin wall gives the ID of the tube a great advantage over the aluminum intakes. Let me fully port match it. I took advantage of a 45* bend that was already in the tube and angle cut the end at the motor. I was shocked at the added HP I got with the pipe but this mod really completed things. With the stock intake I still had flat/4 cycle spots in the rpm range. Now I have smooth power all the way thru and alot more top end. This is a plain stock carb. I'm guessing I have over double the original HP now. A bridge I cross alot that I could barely make 15mph I can now cross at 30mph and could go faster I can accelerate going up it easily now. It really finished the "modded" look I wanted too. Just have to touch up the paint.

P1010130.JPG

P1010131.JPG

P1010132.JPG

P1010134.JPG
 
Good intake. All these engines could do with an intake like that.

The fact that the intake blends into exactly the same angle as the port is good as it helps to focus and project the fuel/air/oil mix directly into your big end bearing upon reaching TDC.

I made my intake as a billet straight one like Jims. Mine was machined from 50mm solid steel bar though lol - took some effort to reduce it down to such a small OD. The flange is thick 8mm as my threaded rod for the studs has thread only formed on the ends - it wasnt "all thread". So the thick flange acts a a spacer.

Obviously I diddn't get to painting it so I opted for a highly advanced, scientifically engineered, Fe2O3 (Iron(II) Oxide) coating... ie rust haha.

I cant speak much about performance for it as it was done at the same time as many other mods(exhaust, tranfer porting, engine balance/true, intake timing change, engine head, etc). But in my previous experiances a larger intake always helps.

bike004.jpg


Despite being on a ~20* angle my carb never leaks, even over severe bumps - its a miracle carb lol. I was able to tune the engine to give a perfect tan brown plug with only a jet drilling and a slight taper change (fine tuning only). Unlike previous carbs where I even machined both float chamber surfaces to dead flat and used loctite - they still leaked!
 
heres some pics of my air intake which works great.
 

Attachments

  • Photo003.jpg
    Photo003.jpg
    120.8 KB · Views: 265
  • Photo002.jpg
    Photo002.jpg
    126 KB · Views: 233
  • Photo005.jpg
    Photo005.jpg
    108.7 KB · Views: 234
  • Photo011.jpg
    Photo011.jpg
    131.5 KB · Views: 226
  • Photo029.jpg
    Photo029.jpg
    117.7 KB · Views: 229
Last edited:
i bought frame feul filter and used for air fitler and it works pretty damm good i forgot but i paid 4 bucks for it and had to drill a couple of holes for it and it works good!!!!
 
I'd like to try some of these mods but what happens to the filter material or filter performance when the bike is in the rain and the filter gets wet?
 
i try not to ride in the rain or get my bike wet at all.
but if you like to go playing outside in the rain or traveling when raining you might want to put some type of plastic cover over it when it rains.
right now i just have a rubber hose and a pipe for air intake and will be using a airbox with filter soon,no worries for me when it rains because my filter will be protected in a plastic box.

if you oil you paper filter that should repell any light rain away from the filter right.
 
Last edited:
I just installing the slimline K&N style filter from Pirate bikes. Under $20 delivered and i think thats the best bang for the buck. Screwed on in under a minute and breathes so much better than the stock filter. The sound was about the same, but i noticed a definate increase in the low to mid speeds on acceleration. Not sure if it helped with top end speed, but certainly has a bit more pick up. Im still in the break in phase so im sure it'll continue to get better. I got the blue framed one with red pleated paper inside. Looks much better too. So i highly recommend this upgrade for both cost and performance.
 
**** the highest performance filter would be panty hose, the second best would be scotch bright or another fibrous material.
 
You must log in or register to reply here.
Back
Top