Slow jet is too small?
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Road Captain
Joined: Nov 2007
Posts: 517
Likes: 6
From: Ottawa, ON
Slow jet is too small?
Weird situation, Ladies n Gentlemen!
Brand new evo. Stock CV carb. I cleaned it (or so I think). Main is 185, pilot is 45.
Extremely difficult to start. Even when hot, needs choke! Idle screw has to be almost all the way in. To get it running at least somehow, the pilot screw has to be somewhere around 4 1/2 turns, almost 5. And the pilot screw gets very very subtle response (don't feel distinct rpm raise/drop).
Suspect air leak? But both plugs look identical - super lean of course - so it's unlikely I screwed up both sides of the manifold. Most importantly, as soon as you pass 1/8 of throttle - everything feels alright. Accelerates great, no hesitation, no sputtering, backfiring, nothing. Only at idle - almost idle - it feels weird.
Thus I think the pilot jet is too small. Some ppl run 48, that's fair enough, but it's a stock engine (with a stock air box and not-so-completely freeflows). So I wonder how the hell factory 42, and sometimes even 40 is supposed to work at all?
Any thoughts, Gentlemen?
Brand new evo. Stock CV carb. I cleaned it (or so I think). Main is 185, pilot is 45.
Extremely difficult to start. Even when hot, needs choke! Idle screw has to be almost all the way in. To get it running at least somehow, the pilot screw has to be somewhere around 4 1/2 turns, almost 5. And the pilot screw gets very very subtle response (don't feel distinct rpm raise/drop).
Suspect air leak? But both plugs look identical - super lean of course - so it's unlikely I screwed up both sides of the manifold. Most importantly, as soon as you pass 1/8 of throttle - everything feels alright. Accelerates great, no hesitation, no sputtering, backfiring, nothing. Only at idle - almost idle - it feels weird.
Thus I think the pilot jet is too small. Some ppl run 48, that's fair enough, but it's a stock engine (with a stock air box and not-so-completely freeflows). So I wonder how the hell factory 42, and sometimes even 40 is supposed to work at all?
Any thoughts, Gentlemen?
Yep,,means you arent getting fuel through the idle circuit.
You could have had something in the bowl that found its way to the pilot.
Its such a small hole that it takes very little to cause a big problem.
Wouldnt be the first time ive had to take a carb apart even after cleaning it.
You could have had something in the bowl that found its way to the pilot.
Its such a small hole that it takes very little to cause a big problem.
Wouldnt be the first time ive had to take a carb apart even after cleaning it.
Road Captain
Joined: Apr 2012
Posts: 628
Likes: 14
From: Sweden via Bisbee, Az.
I had same issue with a 45 and I was SURE that all was cleaned, but low and behold after tearing it apart again and looking closely, a little fleck of black stuff was caught and that made the difference. But you say that it's a new cv... damn. maybe some gungk got in there anyway??? just from having run it?
Road Captain
Joined: Apr 2012
Posts: 628
Likes: 14
From: Sweden via Bisbee, Az.
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Road Captain
Joined: Mar 2008
Posts: 601
Likes: 6
From: Aruba
Yep,,means you arent getting fuel through the idle circuit.
You could have had something in the bowl that found its way to the pilot.
Its such a small hole that it takes very little to cause a big problem.
Wouldnt be the first time ive had to take a carb apart even after cleaning it.
You could have had something in the bowl that found its way to the pilot.
Its such a small hole that it takes very little to cause a big problem.
Wouldnt be the first time ive had to take a carb apart even after cleaning it.
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