Idle screw, hp carb dellorto Sha clone

wan37

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So if those are your picture's its never going to work! Check below. You need or air leak .Hope this helps.
 

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ycodryn

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Are you talking about the nylon round thing? I have it and I`m puting that first and then the carb. When I`m removing the carb, the nylon remains attached to engine intake. I think that I`m gonna bore that mofo and give it a venturi effect.
Edit: your opinions about this, should I drill a bigger jet hole until my other jets will arrive? Or it needs less fuel and more air?
 

Karl Snarl

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This carb is just evil. After grinding the slide, still won't idle. And I see too much smoke VS the old carb.
I add a hole about half the size( maybe slightly smaller than half the size) of the bottom hole, in the middle of those two holes in the emulsion tube. An you want the tube holes facing away from the air filter. They won't allow fuel to flow properly facing the air filter.
 

ycodryn

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An you want the tube holes facing away from the air filter. They won't allow fuel to flow properly facing the air filter.
The only holes from the air filter side are those. If I'm rotating them, the idle one from opposite does not align right. As for the spark plug, I will clean it next time when I'm mounting again the evil carb and take a photo after.
Edit: should I unscrew the tube and solder those holes? Why 2 holes there anyway? Later today I will unscrew it anyway and check all the holes.
 

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Karl Snarl

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The only holes from the air filter side are those. If I'm rotating them, the idle one from opposite does not align right. As for the spark plug, I will clean it next time when I'm mounting again the evil carb and take a photo after.
Edit: should I unscrew the tube and solder those holes? Why 2 holes there anyway? Later today I will unscrew it anyway and check all the holes.
Those holes are where the fuel comes out. Adding one between the two there helps regulate the fuel better. Instead of a nice bottom, crap transition and a nice full throttle, it helps even it all out. That is why they should be on the backside. If on the front, the incoming air just shoots into the bowl. You can play with the size, but I always just added a smaller one between the two there and it really helps smooth everything out.
 

ycodryn

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On the back I have 3 more holes, idle included. That's why I was asking. If on the back the holes jets trough the engine, in the front why the holes?
 

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ycodryn

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Removed the tube, made some adjustments, tried again, no idle. I think that is just a really bad Chinese clone. My next step is to search a dellorto Phbg 19mm. Pro or cons?
Edit: here are some photos with the emulsion tube. That part with 4 holes, 2 are for throttle, 1 for idle and last one for nothing because is blocked by carb casting.
 

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Karl Snarl

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Big holes go back side ( toward engine) little hole lets a venruti effect though to let atmospheric pressure push fuel up the tube. Extra hole I'm saying add, goes on back side, where you are having the leanest reading on your plug. It helps to even out everything. Sometimes it's bottoms, sometimes top, etc. I have usually jetted for the top, and added the extra smaller hole down lower. That smaller tiny hole is about the right size to add in. That one already there is for Idle. If you jet it all good up top, and everything is good, but idle is lean, slightly widen the idle hole. don't add the extra hole if you are getting good mid and upper, just slightly widening the idle hole may do the trick. Before doing it, read up on the venturi effect and how your carb works. What I am saying will make more sense and you'll understand where you need to add it, or widen.
 

ycodryn

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I understand what you are saying about extra hole, hole positions etc. I'm waiting for other jets to test them. If then is still not idling, I leave the nt type.
EDIT: What would you recommend, a Mikuni VM18 or a Dellorto PHBG 19mm?
 
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