Need performance advice

Discussion in 'General Questions' started by Cylon, Sep 24, 2015.

  1. Cylon

    Cylon Member

    Hey all I've built three bikes in total and I ride with my wife about 3 days a week for about 50 mile round trips it's amazing, I've got them both tuned perfectly but her bike seems to run about 4 mph faster I get to about 32 on mine hers can haul to 36 and it climbs Hills quite a bit better we both use the 44 tooth sprocket. It's not a super big deal to me but I want to go up Hills better I've already got the Nt speed card and it did nothing I also drilled a small hole in the exhaust baffle and that as well did next to nothing. Do anyone have any tricks that doesn't include a bigger sprocket or porting. Also her bike has maybe 1100 miles mine has about 400 because she uses hers for work I don't. I also know they build all these bikes differently. I know weight could be a issue as well but it's not I gps tested it with me on it and got the same results and I'm 20 pounds heavier. I'm lost.

    Would a expansion pipe or high compression head work? Last hp pipe(banana pipe) I had though didn't really do much so I traded it to my neighbor for a cdi kickstand and a nt speed carb.
     
    Last edited: Sep 24, 2015

  2. Cylon

    Cylon Member

  3. butre

    butre Well-Known Member

    that head is a foreign made copy of this one
    http://shop.crmachine.com/product.sc?productId=48&categoryId=15
    get the original, you won't be disappointed.

    I know you say you don't want to port it but if you're willing to break out the dremel and start cutting holes in your piston then a reed valve will be a much bigger upgrade for about the same price.
     
  4. Cylon

    Cylon Member

    Do you have a video guide or a web guide on how to do the proper cuts? if so I would be willing to go ahead and spend the money on the bits i would need.
     
  5. butre

    butre Well-Known Member

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    Cylon likes this.
  6. jaguar

    jaguar Well-Known Member

    butre you overdid it on that piston hole. your carb is maybe 18mm and your hole is maybe 50mm. the skinny bottom will break.

    the guy was asking for easy modifications, which changing to a reed valve intake is not.
    EASY:
    using sandpaper and glass to grind down your stock head for more compression.
    making your own head gasket to not lose any of the new found compression (which the stock aluminum gasket will)
    using an iridium spark plug
    putting an aftermarket CDI on
    making your own intake extension (for more low rpm power)
    putting on a less restrictive air filter
    jetting your carb to perfection
     
  7. Cylon

    Cylon Member

    I drilled the holes then the motor wouldn't start so I pulled out the piston of my spare bike then it ran I also ported the intake a bit with my dremal didn't change a thing. I have a solid rear tube which I think might be slowing it but now it's running quite bad even with a new piston. I'll try adding a air tube to the rear when I'm less annoyed with the bike. Have a high comp head coming in the mail, hope it works if not I'll sell the bike.
     
  8. butre

    butre Well-Known Member

    the carb is 22mm and the skinny bottom hasn't broken in 400 miles. it's only a bit wider than the intake port, and the height affects duration, not velocity. my method for determining the right size was to start small and keep getting bigger until it stopped making more power, but it never stopped making more power.
     
  9. butre

    butre Well-Known Member

    did you get the reed valve?
     
  10. Cylon

    Cylon Member

    No I didnt get a reed valve I just got the high comp head. I dont want to spend that much money on a part right now I have to many bills could only afford the high comp head. I also bought new tires and thick air tubes rather then that solid tube and now the bike is running much much faster Im very happy about that. Heres what it looks like with the new tires. 20150926_193018.jpg
     
  11. Cylon

    Cylon Member

    Also this is what I did to the piston and it made it so the bike didnt run so I had to get a new piston put in.
    20150925_110835.jpg 20150925_110845.jpg
     
  12. butre

    butre Well-Known Member

    my advice was in regards to reed valves.
     
  13. Cylon

    Cylon Member

    Oh I see now I guess Ill keep that piston kicking around and Ill try to find some reeds made for these motors after I can afford it.
     
  14. butre

    butre Well-Known Member

    mzmiami on ebay sells a pretty good one for $40. pick that up sometime and you'll feel the difference right away
     
    Cylon likes this.
  15. Cylon

    Cylon Member

    how does a reed work and should I put the piston back in that I put holes in?
     
  16. Cylon

    Cylon Member

    What reed would I need with my stock carb? they have a lot of choices is it the 40mm or the big carb one?
    After looking around it seems like a 40mm is the one for the stock carb i think ill order it in two weeks its getting cold here now not much time left to ride but id love to try it before snow fall.
     
    Last edited: Sep 26, 2015
  17. butre

    butre Well-Known Member

    riding in the snow is about the most fun you can have
     
  18. butterbean

    butterbean Well-Known Member

    If you drilled holes in both sides of that piston, its useless.
     
  19. Cylon

    Cylon Member

    Nope
     
  20. johnsteve

    johnsteve Member

    so what would be the best pattern for drilling out a piston to get the best performance out of the reed valve? Was in on the prior page? I am thinking about doing this one day.
     
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