Reed, or not to Reed?

Discussion in 'Performance Mods' started by geebt48cc, Oct 27, 2012.

  1. geebt48cc

    geebt48cc Member

    QQQ.jpg Yeah, I've done quite a bit of work to this bike.........I've got coming as well the RockSolid reed valve. I'll be using a speed carb with it. After the motor was milled down, SBP expansion, and Jag CDI, I'm trying to figure out what would be a good jet size to go with at 2000ft for reed valve.

    I pray that this reed valve helps the torque, I'm chancing it, because I've been using a 7" extention intake, from jug to carb. Much,Much better torque, but I do believe that reed valve will even do better?!~ I'm hoping that with the higher compression that the reed valve is going to do its thing. I've port matched all, but not opened up engine?!!

    We'll see....................Did reed help yours? What kind?

  2. Fabian

    Fabian Well-Known Member

    It sounds like you are expecting a lot more out of this reed valve intake than it will actually give you.

    It "will" give you improved low and midrange torque, but it "won't" give you Much,Much better torque

    If you already have Much,Much better torque, then you're best off sending the reed valve intake back to the vendor, because it "will not" match your expectations; in fact, you will be sorely disappointed with the results, more so, if you try and bolt the reed valve to the rear of the 7" intake.

    Expecting the higher compression to make the reed valve more effective is also a pipe dream - it won't happen
  3. geebt48cc

    geebt48cc Member

    No, No, Fabian.........I would totally do-away with extension! The reed would only be mounted directly to cylinder jug.............I just have hopes that it's as good as putting on that simple 7" intake extension.?

    Sure, I don't expect it to be something it's not........just want it to be equivalent, with expectations of making it stronger after doing a few mods internally, like base jug porting and drilling piston out for better fuel circulation.

    See, the only reason I made purchase, is because a true higher performance 2/stroke always has reeds.......... It opens doors for even better mods. (I hope)
    Last edited: Oct 28, 2012
  4. Fabian

    Fabian Well-Known Member

    Bolting the reed valve intake in place is relatively simple, or at least i found it simple; my two next door neighbours also found it to be fairly simple: a little grinding of one of the lower cooling fins and it's job done.

    Just make sure you don't accidentally grind into the machined face of the intake port.
    It helps to cover it with 5 layers of protective duct tape when grinding the recess for the reed valve, and to stop any aluminium filings getting into the intake port.
  5. geebt48cc

    geebt48cc Member

    I just wonder if I'll need to increase or decrease jet size on the speed carb used? I'm right at 2000 ft above sea level.

    ?? (PS- I saved the Heaven/H.E.L.L. ideas..............true)
  6. Fabian

    Fabian Well-Known Member

    The answer is a simple one: don't bother wondering about it before time; just bolt up the reed valve intake when it arrives; attach your carburettor and get some warmth into the engine by idling it for 1 or 2 minutes, then pull out the old plug and install a brand new spark plug to check the air/fuel mixture with a plug chop.

    Personally, i would install an exhaust gas temperature gauge (EGT) and a cylinder head temperature gauge, as it makes life so much easier when zoning in on the correct jetting.
    To make tuning completely idiot proof a wide band air/fuel ratio gauge can also be fitted (which will shortly be fitted to my bike), giving me another tasty gadget to monitor, because i need to know exactly what the air/fuel ratio is doing; millisecond by millisecond :grin5:
  7. geebt48cc

    geebt48cc Member

    Fabian, I would appreciate you sending me a link on the ratio/fuel gauge you're talking about. What kind of average speed do you run your bike? What does it run at higher speeds?
  8. Fabian

    Fabian Well-Known Member

    Koso Wideband Air/Fuel ratio gauge:

    The only issue is that it requires a 12 volt supply and 2 amps (24 watts) to power the gauge and sensor; necessitating onboard power generation, which the standard magneto can't supply, "unless" your 2-stroke bicycle engine is equipped with a combined electric start and 5 amp (60 watt) generator :banana:
  9. Fabian

    Fabian Well-Known Member

    Speed wise, my bike does 3.5 MPH at 4,800 rpm, hauling a bicycle trailer with a gross (loaded) weight of 200 lbs up a 20% grade.
  10. jaguar

    jaguar Well-Known Member

    If with a std 44 tooth sprocket you do 29mph at 6500 rpm then you'd have to use a 275 tooth rear sprocket to achieve such low speeds.
  11. Fabian

    Fabian Well-Known Member

    A SickBikeParts shift kit with the tetra chain wheel modification and Shimano 29'er cassette modification allows you to travel at 3.5 miles an hour spinning 4,800 rpm.