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Thread: How to install an air cooled big bore kit! Step by step w/pics!!!

  1. #16
    apriliaforum expert scootnfast's Avatar
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    Now replace the four nuts onto the head and tighten them up pretty snug.
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  2. #17
    apriliaforum expert scootnfast's Avatar
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    Now re-install the plastic cover over the head and re-attach the exhaust. Then put your spark plug in.
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  3. #18
    apriliaforum expert scootnfast's Avatar
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    And that is it for the cylinder installation, now we need to change your reeds to the ones that came with the kit. I don't know that this is really neccessary, I think the stock steel reeds work fine, but they say the carbon reeds let a little more gas in, so I went ahead and installed them.

    First start by removing the four screws that attach the intake from the carb to the motor. Your reed cage is located under this. 2 of the screws are safety screws which have a post sticking up out of the middle. You will need to get a 5mm allen head wrench with a hole in the center of it to remove these. I simply drilled a hole into the end of one of my allen bits. I have heard of people using vise grips to remove these also, although I wouldn't reccommend doing this.
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  4. #19
    apriliaforum expert scootnfast's Avatar
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    With the intake removed, the reed cage will now be exposed. Simply pull the reed cage out from the motor.
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  5. #20
    apriliaforum expert scootnfast's Avatar
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    Now remove the screws that hold the reeds onto the reed cage.
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  6. #21
    apriliaforum expert scootnfast's Avatar
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    You will notice the carbon fiber reeds have two holes for each screw. Lay the carbon fiber reed onto the old reed and determine which of the two you need to use compared to the old.

    Also there is a notched corner at the top of each reed. I don't know why this is here, but I was sure to line them up. If you switch to the other side, all you have to do is turn the reed over and it will work on both sides. I installed my reeds with the malossi facing toward the intake. I don't think it makes any difference as to which way you do this.
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  7. #22
    apriliaforum expert scootnfast's Avatar
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    Once you have the new reeds attached, they should look like this.
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  8. #23
    apriliaforum expert scootnfast's Avatar
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    Now replace your reed cage back onto the motor and re-attach the intake.

    That is it for the entire installation. Now all you have to do is put everything back together! Start by putting th frame back on and sliding the main chassie bolt through. This can be pretty difficult to get lined up, it is deffinately a 2 man job. Once the main bolt is in, snug the nut up and start re-attaching all your hoses, cables and wires. Don't forget to re-attach your brake cable!!! After you get everything re-attached, bolt your shock back on and start it up. Don't run the throttle up too high, you need to wear your rings in a bit before doing this. Try to stay at about half throttle for a while. I usually do this for the first 5 or 6 times ridding, which is about 5-10 miles each run, and letting the engine cool entirely before riding again.

    Check your spark plug for jetting. You may need to adjust your needle if you are running your stock carb. You don't want to run too rich or lean.

    Well I hope this will be informative for some of you. And as I said before, feel free to add suggestions!!!!

    I got this kit from MOTOTEK here: http://www.mototek.com/products1_part8.htm - Or give them a call to get a big bore kit for your particular model scooter at 512-218-4466.

  9. #24
    apriliaforum expert scootnfast's Avatar
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    PERFORMANCE RESULTS!!!!

    OK, now I bet you are all wondering, if I spend the time and the money on this, will it all be worth it??? I say YES!!!!

    Before the kit, I was running stock everything (Derestricted) except an arrow exhaust and a .8mm jet in my carb. I was holding 45MPH with no problem. After the big bore kit, I saw a HUGE increase in power and acceleration, but not much increase in top speed. Maybe about 3MPH more on the top end. Then I installed a gear kit and a new variator. I played around with the roller weights for a while, and now I am getting about 53MPH steady. I can hit about 58MPH ducked down and going downhill.

    I think the gear kit is A MUST HAVE when you have a big bore kit. Before I installed it, the engine would wind out so fast. Now it doesn't wind out as it did before, and it deffinately increased my top speed!!! The gear kit is the same as the gear kit for an SR ditech. (I know because that is what I bought, and it works great!!!) You can see how to install your rear end gears here: http://www.apriliaforum.com/forums/s...&threadid=8903

    I am excited to see how much differance a larger carb is going to make on this. I am still currently running stock carb with .8mm jet.

    These speeds were done by my wife following me in the jeep to see how fast it goes. It is funny, I burry the speedo at about 40-45MPH, but the speedo goes up to 50!!?!?!? Darn these inaCcurate speedo's!!!

    Good luck installing yours!!!
    Last edited by scootnfast; 09-08-2003 at 06:32 PM.

  10. #25
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    Thumbs up

    scootnfast,

    Dude, its a nice thing that guys like you spend time and effort on providing step by step instructions for newbies. Just an additional info on the reed replacement, replacing the stock reed petals (steel or fiber material) w/ carbon fiber ones would improve throttle response. Reed valve controls the gas/oil & air flow from the carb to the the crank with response to the twist of the throttle. Unlike stock reed petals, these reeds may flutter in high RPM condition, thus using carbon fiber reeds would minimize the fluttering problem resulting to better acceleration and even top speed.

    Carbon fiber reeds have several thickness (usually 0.3, 0.35 & 0.4mm). But using too thick CF reeds may not perform well on mild set-up that may reduce top speed. Thicker CF are used on high RPM set-ups. Better consult Tiba for thickness recommendation.

    I myself like the sound of engine using CF reeds, just like tearing the road apart when revving to the max!

    Keep up the good work dude.

  11. #26
    apriliaforum expert scootnfast's Avatar
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    I agree wacko_dz, the only thing that I am saying is that I have purchased a malossi CF Reed set, and I tried all three different thicknesses, and I really don't see any differance between these three and stock.

    Thanks for the positive words man!!
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  12. #27
    Moderator DRT-Tuning's Avatar
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    [i] recommendation.

    I myself like the sound of engine using CF reeds, just like tearing the road apart when revving to the max!

    Keep up the good work dude. [/B]

    You can HEAR the use of metal/CF reedvalves?????
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  13. #28
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    Originally posted by DRT-Tuning
    You can HEAR the use of metal/CF reedvalves?????
    DRT, Not actually hearing the motion of the reedvalve but I had noticed the big difference in the sound of my pipe & as well as of the open carb, between the stock reeds compared to the CF reeds & of course the engine was set to rev on high RPM.

    Peace Bro...
    Last edited by wacko_dz; 10-02-2003 at 08:46 AM.

  14. #29
    apriliaforum newb cyface's Avatar
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    Tool for Manifold Cover

    AF1 sells the "security" hex wrench needed to take off the manifold cover and change the reeds.

    http://www.af1racing.com/store/Scrip...idproduct=1282

    I ended up using a dremel tool to grind down the security posts just enough to get a normal hex wrench in there, but the wrench above is a better option.

    Good luck!

    Tim

  15. #30
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    Don't always rely on the notch on the new CF reeds to tell you which way round they go, on the Polini kit I did for a friends Yamaha Zuma it was on the wrong corner, but it was still fairly obvious which way to install the reeds cause there was print on the back side of the reed. (And of course the reeds are slightly curved)

    Also, as a tip from a guy who rebored two stroke cylinders for 20 odd years (my father), you can carefully grind/smooth just a little off the sharp edges of the ports in iron cylinders with a rotary tool if you wish, as it can reduce the chance of ring breakage and hot spots when bedding in a new cylinder, and just generally make for a safer easier running in period.

    And make sure everything gets a light coating of two stroke oil when putting it all together, pins, pistons, and even a touch on the inside of a new carb can help cause they come rather dry when new.
    Oh and really make sure you prime the oil pump and all lines before you attempt the first start, better to much oil and a nice cloud of smoke on first start-up than anything running dry at any time.

    Oh, and you can re-torque the head bolts after the first run, and when it's done running in.
    Last edited by Bishop; 05-15-2004 at 10:49 PM.

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