250psd Posted July 14, 2008 Report Posted July 14, 2008 My mods include Stage IV 2 into 1 carb 33mm Keihin PWK, Timing at +4, Dyno Port 2 into 1 exhaust, Twin Air filter with airbox at about 1500ft above sea level. I just started getting good at my Mikuni's and now switched to a Keihin. I don't have this set up on the quad yet but when I install I want to have a couple of jets handy to get me started. What is a good starting point for my set up? Pilot and mains sizes? The carb currently has a 48 pilot and 160 main. Any help is appreciated. Thanks Dominic Quote
Misssppelllleddd Posted July 14, 2008 Report Posted July 14, 2008 Ok start with what you got. I know that this is a bitch but it has to be done. A 2-1 33 carb set up are a little different than 2 33mm carbs. I have the same set up. I bought it from Trinity racing and they set it up. I had a 175 main and the stock air that came with the 33mm carb. I had Pro-Circuits and no timing advance. What really helps out with the single carb is that there is constant air flow through one carb and it never stops until you let off the throttle. Do a spark plug check and adjust off of that. After that you should be good. If you bog down then drop down a size or two on the main jet. Quote
ahcgt Posted July 15, 2008 Report Posted July 15, 2008 Ok start with what you got. I know that this is a bitch but it has to be done. A 2-1 33 carb set up are a little different than 2 33mm carbs. I have the same set up. I bought it from Trinity racing and they set it up. I had a 175 main and the stock air that came with the 33mm carb. I had Pro-Circuits and no timing advance. What really helps out with the single carb is that there is constant air flow through one carb and it never stops until you let off the throttle. Do a spark plug check and adjust off of that. After that you should be good. If you bog down then drop down a size or two on the main jet. Not to hijack this thread but I also have a 2into1 38mm. It bogs a little taking off and on top end. Main jet too big? Quote
Misssppelllleddd Posted July 15, 2008 Report Posted July 15, 2008 Not to hijack this thread but I also have a 2into1 38mm. It bogs a little taking off and on top end. Main jet too big? Yeah that is what happened to me. I had most of the trouble in the mid range but once I changed out the main jet to a smaller one I was okay. Quote
250psd Posted July 15, 2008 Author Report Posted July 15, 2008 Thanks for the replys but bogging on take off would be a pilot problem or reeds IMO. At the top would be a main jet problem. Your plugs should tell you if you are lean or rich on you main. Bog could be from either. I guess i'm answering my own question in a sense but i'm not used to the Keihin carbs and need a starting point with my setup. I want to kind of nail it the first couple of rides and have the jets I need instead of riding and ordering jets after a failed attempt. Quote
Misssppelllleddd Posted July 15, 2008 Report Posted July 15, 2008 You are right about the pilot jet but your main jet could be allowing excess fuel into the system too quick. That happened to my friend's 'shee. Exactly. He had a problem with low end bogging and we just changed the main jet and it worked just fine. If you want a quick fix without messing with the carb then run 20cc-21cc domes. Just run the right fuel. Quote
250psd Posted July 25, 2008 Author Report Posted July 25, 2008 I actually think it's a 34mm not a 33mm. Anyone else with some input? Quote
LS1Inferno Posted July 29, 2008 Report Posted July 29, 2008 (edited) Nobody? Yeah ditch the 2 into 1 and get another matching carb i hate them and a lot of people feel the same but to each his own. i bought two used bikes with them and both were burnt up by prevoius owner, And how funny does a banshee with one pipe look? Edited July 29, 2008 by LS1Inferno Quote
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