Dellorto Main Jet - too rich problem

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when you say removed the pumpers? 125 is a good reference size, doubt you would go overrich unless badly worn parts on the slides, or slightly not seating cold enrichment plungers, common problem.
 
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iis_iis said:
when you say removed the pumpers? 125 is a good reference size, doubt you would go overrich unless badly worn parts on the slides, or slightly not seating cold enrichment plungers, common problem.
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I removed the actuators to disable the Accel pumps.
I initially suspected the choke plungers so I replaced their seals and made sure they seat completely.
Is there a way I can check for worn parts on the slides- what measurement would be relevant e.g. diameter?
 
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It usually involves sticking a finger into the inlet track and wiggling the slide. Even then new slides cost a bomb and the carb body wears as well. I tried getting mine Teflon coated years ago to take up wear, it worked great on the single Delordo in my Husky 350 but failed horribly in the 3 on my 3c, it blistered and couldn't be smoothed out. Having a divot, indent in the choke plunger bottom rubber,they should be smooth, is classic or not having them bottom out and hang a bit up is another. Your doing better than most, a hell of a lot have 145mains. Big holes make big power apparently. BTW don't do that.
 
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That Teflon coating the slide idea came from one of the blokes who ran Off-Road bike tours to the Tip Of Cape York. He ran a fleet of 40 DR 400 Suzukis that regularly did that 1000k trip of deep sand whoops and they flogged out carby slides constantly.
 
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Gerald said:
Check the choke plungers for even movement, closing all the way when off.
Main jets 120 is a quick swap, wouldn't go any smaller.

Gerald
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Ok, that's what I was wondering-- what would be the smallest practical jet size. I'll try the 120 to see if there is any improvement. (y)
 
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Vince said:
Definitely, I forgot about that one. All that needle up and down flogs the needle jet, also called an emulsion tube to an oval-shaped hole.
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... because of slide wear - too much back and forth play in the slide, needle wears front and back of emulsifiier tub un near the venturi. I'd also give several mm of freeplay to the choke cables. The choke lever travel will easily cover that and open the choke slides to fully open. Cheap insurance.
 
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Original factory spec is 118 main jets, although fuel recipe may have changed a bit since then. Last time I put my bike on the dyno when it still had Dellortos on it (about 10 years ago I'd guess - it's got Mikunis now), we settled on 120 mains and the WOT mixture was pretty much spot on. Just a wee bit rich but not enough to bother trying to find a set of original 118 jets. It ran well with the 120s. My engine is Jota spec, but the jet size for the 3C is the same 118.
 
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Dellortoman said:
Original factory spec is 118 main jets, although fuel recipe may have changed a bit since then. Last time I put my bike on the dyno when it still had Dellortos on it (about 10 years ago I'd guess - it's got Mikunis now), we settled on 120 mains and the WOT mixture was pretty much spot on. Just a wee bit rich but not enough to bother trying to find a set of original 118 jets. It ran well with the 120s. My engine is Jota spec, but the jet size for the 3C is the same 118.
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Thanks, I sourced the 120's yesterday so I'll start there and then I can go to 118 next if need be.
 
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Like a panel of interviewers giving the interviewee the once over.... a grin here. Opening up the question time, Air cleaner filter in best condition ( Chuck3cl has all the correct answers and competent setups as read ), preexisting ( similar ) condition of ALL three plugs, ie if a lot of cold crank starts and short road rides. Cold enrichment disengaged once on the ride. Pilot fueling adjustment screw position ( 1 3/4 out usual ) Oring intact on the adjuster screw, proper metal washer also contacting Oring.

Has this motor been running poorly previous and loaded up the exhaust system with oil/carbon build up? Being ejected on upper rpm use.
Wondering what MPG/kms/l are you getting from a tank, 220 k's per tank is usual, had it up to 300 though the off idle was a tad dodgy.

On the road, if brave, open the cold enrichment lever to see if the engine gets fluffy, then open the throttle wide to see if if clears then pulls cleanly. Yes i know, seems opposite perverse to over fueling, need to establish where there is the perceived over fueling Just for laughs, check the 5K ohm resistor spark plug covers for open circuit. Should see about 14K ohms cover center contact to engine case/frame.

Many the series 1 180 will main jet above the lower jet size for the 120 engines. Never needed to go below, 122 on the 180 here and customers iis setup. j
 
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