Friday, January 9, 2009

Carb: Dell Orto S1/20

Specs for the Dell Orto carb for the TV175 S.3:
SH1/20
Bore: 20 mm
Slide: 5914-1
Atomizer: 5899-2
Main jet: 106
Pilot jet: 50
Starter jet: 50
Float weight: 5grms

Over the winter break I decided not upgrade to an electronic ignition and a Casa 186cc kit for two reasons: (1) the bike is a bit rarer and the further I get into this the more stock I lean and (2) the price was about $1000-1200 more. I posted my "wanted" note to LCUSA and Scooter BBS. I got a couple bites for both the stator/flywheel and carb I need. Due to the fact that I have two TV175 engines, both very early on the serial stamps, I need two of each. I emailed around about the stator/flywheel with Michael in PDX who led me to Ming. Ming was selling the carb pictured below for $50.
The carb throttle threads are stripped a bit at the top and therefore it does not sit as well. This is a common problem found with these old carbs. Stickley offers a few possible repairs, including pinching the throttle cable housing and using some Loctite. I bet a heli-coil would work well too and look prettier. There is a machinist with a website "Jonbretta" who will machine the threads into a piping then drill out the threads in the carb and tap it down into place. You probably won't even see the difference when the carb is installed. Ming estimated the cost at $20 for that work. He also knew of a another carb for sale from a guy named Paul for $70 with jets and all. That is the carb pictured below, which I bought. Paul also believes that he has the main jet, which is the only item missing, and he will mail it to me when he finds it. The metal is banged up a little here and there, but what can you expect with its age. Ming's looked better, but suffered stripped threads.
Looking more closely you can see that it is an original stock carb.  Sorry for the poor quality pix above.  I will replace it at some point under natural sun light.It is my understanding that finding a 20mm carb is a bit of a challenge, but finding a 22mm is even more difficult.  Seeing as I have two engines, I want a second carb as well. One option I am looking at is to buy a 20mm carb that came out of a Jet 200 (Serveta -- Spanish Lambretta).  
This carb is a this is a Licensed Dellorto carb stamped: Lic. DellOrto Arbeo Bilbao. This carb will fit the TV175 engine just like the original Dell Orto carb would and function exactly the same. I have a bit of a thing for stock though, myself. It could be a cheaper alternative to use this carb though. The seller, Doug, contacted me via BBS and offer it to me at a good price including shipping and a carb rebuild kit.

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