LCGB Forums

I recently completed a nut and bolt resto on a Jet200 converted to SX frame, fitted with an Italian SX200 pack. It has new standard piston, rings, barrel, head. I fitted an RScoots tuned exhaust and went for a Jetex 22 carb with associated manifold etc and a carved out airscoop. Son of a bitch to start, pulls like a rocket (engine has been GENTLY run in), but overheats and stalls under heavy throttle after having been run a while. I have read since that the Jetex 22 should not be used on SX200. I,ve since refitted a Dellorto SH1/20 and although a little flat, it runs like a dream. Any advice would be welcomed as I now have a couple of hundred quid sitting on a shelf

A lot of people deride the Jetex but a lot of members use them without problem.
Get the correct Dellorto jets for it and also start with a bigger pilot than is currently fitted.
Take out the plastic float and by hand run a small drill bit or round file through the hole that it hinges on and when you put it back together make sure the float hinges very freely.
Also I believe Allstyles can supply an alternative atomiser. You could ring them; like most dealers they are very helpful.
No reason why a Jetex cannot go on an SX 200.

hi Pete
is it possible that the jetex is running weak at full chat (could be missed while running in at lower speeds.)
i've used 4 jetex 22's in recent years, all perform ok and that's on 186 & 225 motors.
20mm delli is the original carb for SX 200.
i know using a jetex carb can be a bit hit or miss and many peeps will just say bin it, my experience has been ok.

If I remember correctly (and I may not...), I recall a discussion on the old forum about the diameter of the drilling from the fuel filter section of the carb to the area above the float valve being smaller on the Jetex carb than on the DellOrto SH2/22. I think it showed up as weakness as high speed, so might be worth checking.

A couple of hundred quid??? That's a bloody expensive Jetex Pete! Jetex carb's are fine imo just change the atomiser and pilot and make sure you have the 200 slide in it.

Rich'

Thanks chaps. I appreciate you taking the time to help a new scooter builder (63 years young). I'm just off to strip that bloody carb.

You may get more joy ditching the scootRS pipe too horrible revvy pipe imho, and there`s probably more jetting info about for a Clubmam and it will be a nice ride

I happily run a Jetex with Dell'Orto jets and Allstyles atomiser on my SIL GP 200 - not an SX I know but I can't think why there would be an issue with a Jetex on an SX200.

I did have problems running with a Scootrs pipe which I gave up trying to cure. I had 3 or 4 seizes with it on two different carbs (one a Jetex the other a PWK/OKO). It went like a rocket through the gears but any sustained speed caused issues. I probably could have sorted it but in the end I put an AF Clubman on it and it's fine now.

Good luck,
Simon.

Just stick with the 20mm