hercalmighty Posted March 31, 2009 Report Share Posted March 31, 2009 Ok here is the deal. I had a stock motor with T6's, VF 2's, open air box and PWK 28's. I was jetted at 48 pilot, N68A needle middle clip, 162 main. The thing ran great, felt perfect. Well I went and built up the motor. I got a 4mil Herr Juggs Dune port, 21cc cut domes, +6 timing, running VP 110 at the same oil ratio as before, and CPI's. I did not change any of my jetting and now Im running rich. Is this normal? I never ran racing fuel before so I dont know if I have to rejet for that. If I do, do I go up or down with my jetting? I also heard from someone (I forget who) that stroker motors have a tendence to pull more fuel through the carbs meaning you have to lean out your carbs. Is this true? Just trying to get an idea if its the motor work and fuel or if I have a problem. Just so no one ask, the pick up gap is set at .018, carbs are clean, leak down was perfect, compression was 172 psi in both, carbs are snyched, air filter is not over oiled, new plugs. Elevation is 300-400', humidity is about 70%, temp is about 60, oil ratio is 36:1 Golden Spectro. Quote Link to comment Share on other sites More sharing options...
sredish Posted March 31, 2009 Report Share Posted March 31, 2009 I did not change any of my jetting and now Im running rich. Is this normal? I also heard from someone (I forget who) that stroker motors have a tendence to pull more fuel through the carbs meaning you have to lean out your carbs. Very possible. You're going to be moving more air through the same hole (carb) at every stroke than you were before. This translates to more vacuum and velocity through that same hole (carb) and therefore it's very likely that it will pull more fuel through with every stroke causing a rich condition. Quote Link to comment Share on other sites More sharing options...
KEVSWS6 Posted April 2, 2009 Report Share Posted April 2, 2009 You should be about a 155 main jet with an air box on it with no lid. Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted April 2, 2009 Author Report Share Posted April 2, 2009 Sorry. I guess I really should be asking what is making the motor run rich now? Is it the fuel or the motor work? Just wanting to know for info reasons. I like to know WHY it is not just here is the answer. I did do the mains like you said Kevin just havent been able to go out and test yet. So its not that Im question you its just me being curius as to why. Quote Link to comment Share on other sites More sharing options...
KEVSWS6 Posted April 2, 2009 Report Share Posted April 2, 2009 I have no idea why it ran with 162 mains in it on a stock stroke with no porting. I have never run that big a jet in those carbs. Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted April 2, 2009 Author Report Share Posted April 2, 2009 Yeah I dont know. Thing ran great with the 162's. When I was running the stock carbs I had 300's and the airlid on and thing ran great with that setup. My bike likes fuel I guess. Quote Link to comment Share on other sites More sharing options...
sredish Posted April 2, 2009 Report Share Posted April 2, 2009 Sorry. I guess I really should be asking what is making the motor run rich now? Is it the fuel or the motor work? Did you not see my response above? Your getting more air velocity and vacuum with every stroke, pulling more fuel than before causing a rich condition. Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted April 2, 2009 Author Report Share Posted April 2, 2009 Im sorry man I did. It sounded like you were saying it as more of an intelligent guess then yes that is it. Plus I figured since Kevin chimed in I would ask him (he did do the porting). I just took you saying possible as you were not 100% sure. Sorry man no ill will or anything. Quote Link to comment Share on other sites More sharing options...
sredish Posted April 2, 2009 Report Share Posted April 2, 2009 Im sorry man I did. It sounded like you were saying it as more of an intelligent guess then yes that is it. Plus I figured since Kevin chimed in I would ask him (he did do the porting). I just took you saying possible as you were not 100% sure. Sorry man no ill will or anything. it's no problem. the reason I say 'it's possible' is because I don't know what else you have on your bike, if your filter's dirty or other things. you'd be amazed what some people miss or look over. so, yes, your bike will be pulling more air with every stroke (makes you think it should lean out right?) but with the extra air comes velocity and vacuum. the vacuum is what makes a carb work, no vacuum, no fuel period. more vacuum means more fuel and now your motor is pulling more fuel than it needs, causing you to have to jet down a little. but...... check your air filter to. :biggrin: Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted April 2, 2009 Author Report Share Posted April 2, 2009 Yeah thats nice and clean. I was just thinking that since I also changed to more of a drag pipe that likes more fuel it would cancel out. Quote Link to comment Share on other sites More sharing options...
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