Howell 70cc daxs modifications

Discussion in 'Performance Mods' started by keystone, May 29, 2008.

  1. keystone

    keystone New Member

    I;ve tried some of the mods I read about on this forum, including removing the base gasket, from the bottom of the cylinder, to increase compression. I had to use a dremmel bit to trim the edge of the cyl. head for piston clearance, I also enlarged the top of the exhaust port and took a little material of the bottom of the intake ports. I left about 2" of the muffler baffle tube remain inside the muffler,and drilled 2 _ 1/4" holes in the cap at the muffler tip. The results were pretty dramatic,mid range torque, is way up . the throttle response is very quick, I also put the carb. metering rod in a drill to spin it while pinching some 360 grit sand paper around it to put a more slender profile on the needle. My bike is still pretty quiet, and so far relieable the only thing else I would do is get a better carb . Just make sure if you deleat the base gasket and use sealer, test fit your cyl. head so the piston doesnt smack the head!

  2. KiDD

    KiDD Member

    What does sanding the needle do for it? Allow more fuel?
  3. fetor56

    fetor56 Guest

  4. BSA

    BSA Guest

    I'm thinking about making these sort of modifications to my next motor. Could you tell me please, how much you shaved of the ports and can you just use a normal file?

  5. keystone

    keystone New Member

    kidd the best way I can explain

    what sanding the metering rod does is allow for a smoother transition from idle speed to part throttle, it got rid of the flat spot i had when cracking open the throttle, cuz these carbs have no air fuel mixture screw. by the way I'm running the E-clip on the top notch, so dont take too much off at one time or you'll have no more adj. to lean it out ... Keystone
  6. spunout

    spunout Member

  7. Egor

    Egor Guest

    There is a lot of info at this post about porting. When you are carving on the intake scavenging ports you should not need to lower them just widen them. The intake runner should be lowered about 1/4" and widened, or you can cut a half moon in the bottom of the piston skirt. Look at the stuff in this post. Have fun, Dave