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22mm Jetex
Posted: Tue Apr 07, 2009 7:15 pm
by onefortheroad
After struggling with a series of Dellorto carbs with stripped choke threads, I bought a Jetex 22mm for my Li 150 with electronic ignition and AF clubman exhaust. Problem is I cant seem to get an even tickover?
Any ideas?
Cheers
Re: 22mm Jetex
Posted: Tue Apr 07, 2009 7:34 pm
by Fireman Ash
Where did you buy it from bud? take it back if it was a dealer or ask them for the carb details and check your jetting, slide etc for your particular set up...is there no way, as Stickys suggests, of doing dare I say it a bodge on the Dellorto or can they be hellicoiled?? just a guess?? good luck anyway
Re: 22mm Jetex
Posted: Tue Apr 07, 2009 9:57 pm
by onefortheroad
Got it from SR- rang them today and they suggested bigger jets but its already got a 118 in it.
Had another play tonight and the plug was bone dry and greyish so i wound out the mixture screw some more. The sticker on the side says do not wind out mixture screw more than 3/4 of a turn and its already about 1 and half turns? Is anyone running one with the screw wound out further than the recommendation?
Cant seem to work out if its dying cos its getting too much petrol or not enough. When i put the choke on it cuts out? Just gonna have to keep running it about and checking the plug and adjusting mixture screw I suppose?
Re: 22mm Jetex
Posted: Tue Apr 07, 2009 10:07 pm
by sean brady scooters
ideally ...it would be better to replace the jetex jets with the corrosponding original dellorto ones...............
Re: 22mm Jetex
Posted: Tue Apr 07, 2009 10:25 pm
by rog60
One the jetex carbs I bought had a blockage in the drilling between the atomiser and the pilot jet. I used a 1mm drill bit to clear it and changed all the jets, atomiser and choke jet to Dellorto ones. I can get an uneven idle now, it starts better and is a little smoother though the slide range. That worked for mine. Some or all of these changes may work for you. Two of my carbs came from Ressurection Scooters. They were fine except for jets!!!
Re Stripped choke threads, there is a another thread on here about this. You may find that a local engineering company can retap the threads and make the piece that goes in. I got one done for about a fiver a couple of years back.
Re: 22mm Jetex
Posted: Tue Apr 07, 2009 10:37 pm
by onefortheroad
Ive replaced the main Jet with a dellorto one- ill have to have a look through my other bits and bobs for the corresponding dellorto ones and replace.
Could this be an electrical /timing fault? Ive replaced the copper wire with a length of silicone HT lead.
Tickover just seems really weak.
Re: 22mm Jetex
Posted: Tue Apr 07, 2009 10:42 pm
by sean brady scooters
sorry to sound confused...............
but what wire have you replaced with a ht lead...............?

and why.........?
Re: 22mm Jetex
Posted: Tue Apr 07, 2009 11:05 pm
by onefortheroad
Sorry- I replaced the copper HT lead with a silicone one- was told that this wouldnt make a difference though?
Re: 22mm Jetex
Posted: Wed Apr 08, 2009 11:26 am
by onefortheroad
I have managed to source the dellorto jets from omes that I already had and have soaked them in petrol over night- I do not have a 5899/4 atomizer but have a dellorto stamped 5899/2.
Can I use the 5899/2 or would it be best to keep the Jetex one in? There doesnt seem to be any difference visually
Re: 22mm Jetex
Posted: Wed Apr 08, 2009 11:46 am
by firekdp
Never liked the silicon leads as they're quite fragile, I believe the conductive core is carbon fibres so any stretching can break them and the normal way of screwing on the HT cap could cut through the fibres rather than bite into them like copper. Not saying this is your problem though.