stroking Posted May 9, 2009 Report Share Posted May 9, 2009 (edited) I have a set of kehin 34mm carbs tat i had a guy TRY to convirt to alcohol,but all i get is a bog.... really bad when you throttle it we have tried EVERYTHING.....drilling mains,big pilot,moving the needle and the outcome is the SAME exact bog we have also changed stator,flywheel,and CDI only thing left to try is coil,but i dont see how that could be the problem. it runs perfect on gas..........but just bogs down on alcohol !!! is there something i'm missing here,what all is needle to run alcohol on these carbs ? also its a 4mill with stock cylinders fully drag ported with 18cc domes PLEASE HELP!!!! Edited May 9, 2009 by stroking Quote Link to comment Share on other sites More sharing options...
dajogejr Posted May 9, 2009 Report Share Posted May 9, 2009 What size did you drill the main and dump tubes to? How far open is the power jet? What needle are you using? what size pilots? Did you gap your plugs down to .018? Quote Link to comment Share on other sites More sharing options...
stroking Posted May 9, 2009 Author Report Share Posted May 9, 2009 What size did you drill the main and dump tubes to? How far open is the power jet? What needle are you using? what size pilots? Did you gap your plugs down to .018? I don't know what size the main is drilled to but i tried three different ones and the out come was the same no change ACT ALL!!! IT'S like no matter what we try with the carb it does the same thing what is the dump tube........powerjet have been on every setting possible. i think the needle are the ones that come with the carb. and no we did not gap the plugs Quote Link to comment Share on other sites More sharing options...
gst_r Posted May 9, 2009 Report Share Posted May 9, 2009 I don't know what size the main is drilled to but i tried three different ones and the out come was the same no change ACT ALL!!! IT'S like no matter what we try with the carb it does the same thing what is the dump tube........powerjet have been on every setting possible. i think the needle are the ones that come with the carb. and no we did not gap the plugs dumb tube is the tube at the bottom of the carb, where the hose of the power jet is attached, it must be drilled....someone correct me if i am wrong... Quote Link to comment Share on other sites More sharing options...
stroking Posted May 9, 2009 Author Report Share Posted May 9, 2009 dumb tube is the tube at the bottom of the carb, where the hose of the power jet is attached, it must be drilled....someone correct me if i am wrong... if that is it then it was drilled out also is there anything that needs to drilled out in the carb besides the main jet ? Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted May 9, 2009 Report Share Posted May 9, 2009 dumb tube is the tube at the bottom of the carb, where the hose of the power jet is attached, it must be drilled....someone correct me if i am wrong... The dump tube is the part of the carburetor body that the slide needle goes through on its way down to the main jet. Be carefull on Keihins once you drill it you cant replace it. That is why you cannot convert keihin carbs from alachol back to gas. josh Quote Link to comment Share on other sites More sharing options...
dajogejr Posted May 9, 2009 Report Share Posted May 9, 2009 I'm not trying to be a dick when I say this, but you really need to read up more on this. You need to know what size jets. You need to know what size dump tubes. You need to know how far stuff was drilled... You tried three different size jets but don't know what size they are.... Get a drill index kit from Harbor Freight, get a digital mic from them as well. You gotta start measuring stuff out. Quote Link to comment Share on other sites More sharing options...
stroking Posted May 9, 2009 Author Report Share Posted May 9, 2009 I'm not trying to be a dick when I say this, but you really need to read up more on this. You need to know what size jets. You need to know what size dump tubes. You need to know how far stuff was drilled... You tried three different size jets but don't know what size they are.... Get a drill index kit from Harbor Freight, get a digital mic from them as well. You gotta start measuring stuff out. give me some numbers what size should they be 1.dump tube 2.main jet 3.what clip on neeedle 4.pilot jet size give me a ballpark to start with. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted May 9, 2009 Report Share Posted May 9, 2009 give me some numbers what size should they be 1.dump tube 2.main jet 3.what clip on neeedle 4.pilot jet size give me a ballpark to start with. As said, you can't remove the dump tubes...and you can always drill them larger. I say .120 dumps, get .118 and .120 mains. Remember, no matter how big the dump tube or main jet is, you can only flow as much as the other. Pilots I'd say 55. No idea on the needle...but it needs to be a richer (thinner) needle. Do you have a power jet in the carbs? Quote Link to comment Share on other sites More sharing options...
stroking Posted May 9, 2009 Author Report Share Posted May 9, 2009 As said, you can't remove the dump tubes...and you can always drill them larger. I say .120 dumps, get .118 and .120 mains. Remember, no matter how big the dump tube or main jet is, you can only flow as much as the other. Pilots I'd say 55. No idea on the needle...but it needs to be a richer (thinner) needle. Do you have a power jet in the carbs? yes on the power jets i'll go do some measuring and see where i'm at right now. Quote Link to comment Share on other sites More sharing options...
stroking Posted May 10, 2009 Author Report Share Posted May 10, 2009 i got another set of carbs that were on alcohol but they don't have powerjets.........i want to try them,if anyone has ever heard of running alcohol without powerjets? Quote Link to comment Share on other sites More sharing options...
johstoncounty banshee Posted May 10, 2009 Report Share Posted May 10, 2009 so did you ever figure it out i am trying the same thing you did. But i am not using power jets i added a fuelpump. Quote Link to comment Share on other sites More sharing options...
Natemills8 Posted May 10, 2009 Report Share Posted May 10, 2009 Are your carbs PJs or PWKs? Quote Link to comment Share on other sites More sharing options...
dajogejr Posted May 10, 2009 Report Share Posted May 10, 2009 i got another set of carbs that were on alcohol but they don't have powerjets.........i want to try them,if anyone has ever heard of running alcohol without powerjets? If you ask Dan Hull, he'll say if you don't have triple port exhaust, you don't need a power jet on a stock cylinder motor. I like having them...just in case. so did you ever figure it out i am trying the same thing you did. But i am not using power jets i added a fuelpump. Don't confuse the need for more fuel/air with the need for more fuel volume. You only need a fuel pump if you're running the bowls dry, but if you're not mixing enough fuel and air, a pump won't help or fix that. Why give up on the PJs. Measure things out, buy a rich needle, and give it a shot. Quote Link to comment Share on other sites More sharing options...
stroking Posted May 10, 2009 Author Report Share Posted May 10, 2009 If you ask Dan Hull, he'll say if you don't have triple port exhaust, you don't need a power jet on a stock cylinder motor. I like having them...just in case. there are NOT triple ported. by the way how do they triple port stock cylinders??...... after looking at the cylinder i don't see how they do it without cutting into the water jacket.. im going to try the ones without the powerjets.........i bought a drill set so now i can drill the main to the proper size,should i still stop at .120 without the powerjets or should i go bigger ? Quote Link to comment Share on other sites More sharing options...
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