Tuning OS's

[Troy Newman]

Tuning OS'sThe Webra can be turned down to fit the OS case. It is not a bolt on replacement. Some simple machine work and it fits. It also works the same.


TN
  ----- Original Message ----- 
  From: Dave Smith 
  To: discussion at nsrca.org 
  Sent: Thursday, January 22, 2004 10:14 AM
  Subject: Re: Tuning OS's


  Hi Eric:  A few months previous I tried to buy an M/C carb for my OS 1.40"s.   I was told they were no longer available in NA,due to lack of denand.

  I tried to buy one from Singapore,and just missed their last one.  Glad now I missed it as price was atrocious

  About that time Webra arrived on the scene with their M/C Carb,which seems to be quite popular.

  (1)    Does OS perhaps have plans to bring their MC Carb back to NA,at a reasonable price.

  (2)    Will The Webra MC Carb fit the OS Case,or be easily modified to do so?

  Cheers,,,,,,,,,,,,,Dave
    ----- Original Message ----- 
    From: Henderson,Eric 
    To: discussion at nsrca.org 
    Sent: Thursday, January 22, 2004 12:32 PM
    Subject: Tuning OS's


    My time with the OS 1.40RX goes back to 1997/8 when I bought four of them and a tuned pipe from a small English hobby shop, on one of my trips to the UK. Although I don't own the motors anymore I know where they are. :-)   The UK customs had a fit when they saw the pipe on their x-ray machine... Just made the plane in time...

    The first modification was a new carb-jet that OS provided FOC to cure a mid-range gurgling problem.  Back then,  the motor was a novelty and not taken seriously, even though it pulled my old Hydeout vertically out-a-sight.  Things went quiet for a while and around the year 2000 there was an upsurge of interest. The EFI caught a lot of attention and then the experimenters started working on their 2-cycles of all types. The second modification was to fit stainless steel bearings :-)

    The price of the OS 1.40  EFI made us look at the RX again. Dave Shadel came out with a piston and liner. Fuel was modified to meet the spec's that OS had always listed. Coolpower was always around 15/17-18 and often proved to be the best fuel for the average pattern OS 2-c pundit. The OS 1.40 RX had a different shaft and carb by then. The new carb had a bigger throat and the shaft had a narrower mouth. Never got to try an old shaft with a new model carb. Did cut a 1.40 two plug head that was never tested. Found out that one OS "F" did the job with less plug-fuss.

    The Shadel liner is not a must but does give more power. I like it because it is an aftermarket add-on that anyone could fit. Another aftermarket is the OS mixture carb. I first heard of this from Jeff Carrish. I then got to fly one on Dixie-Chicks-Earl's Temptation. The Webra MC testing got me interested and then the flight-experience convinced me that this carb (Approx. $79) makes a big difference. You have five points on the carb and seven on a JR 10X. You can adjust the carb to perfectly match the behavior of almost any pipe. With the OS Hatori and this carb on a 1.40RX it was just like flying the 1.40 EFI. ( This motor BTW still had the std liner etc.)

    I was so impressed with the tunability of this carb that I am fitting one to my 1.60 as soon as it arrives in the mail - checking for it every day...!!

    As much as I like to only do easy after market mods, I did break down with the OS 1,60. The 1.40RX pump was so good that I grafted one to my motor and ran it last season. The 1.60 Carb worked just fine and I am told that the 1.40 RX carb  works even better, at least in Norway or Sweden? (They  all have 15 mm openings in the crankcase).  An OS 1.60 FX w/pump and an OS mix carb should be pure fun to play with and of course, fly!

    I still hope that OS will come out with a rear exhaust 1.60, (or more),  w/pump. 

    Is winter over yet? 

    Regards,

    Eric. 
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