fastrthnu Posted February 4, 2008 Report Posted February 4, 2008 Would a 39mm carb on a 4mm stroked/stock cyl mx ported motor be sufficient? All the bolt ons done. Or to much for a stock stroke with everything else? Quote
locogato11283 Posted February 4, 2008 Report Posted February 4, 2008 stick with dual carbs. 33mm pwk or 35mm pwk. Quote
Snopczynski Posted February 4, 2008 Report Posted February 4, 2008 (edited) 39 is too big. It should be ok with a 35mm or a 36mm. Dual 35mm is also too big. I wouldn't use over a 32mm dual setup on a ported 4mill. Only time it needs a ton of carb, is if it is a drag racer. Edited February 4, 2008 by Snopczynski Quote
BigRed350x Posted February 4, 2008 Report Posted February 4, 2008 39 is too big. It should be ok with a 35mm or a 36mm. Dual 35mm is also too big. I wouldn't use over a 32mm dual setup on a ported 4mill. Only time it needs a ton of carb, is if it is a drag racer. I run dual 35's on my old 4mil and run dual 38's on my current bike and it loves them big. I've run all the way from 33's to 39's on my 4mil duners and all of them run good, just depends on what you really want to do with it and where you want more power/response. Quote
Snopczynski Posted February 4, 2008 Report Posted February 4, 2008 Just cause It runs good, doesn't mean its running the best it can. We do alot of dyno testing, and a good majority of the bikes out there with 35mm pwk's are way over carbed. I have seen cases were when the carbs were sized down 7mm to a set of 28's, it picked up2-3 midrange hp and the topend stayed the same. Quote
fastrthnu Posted February 4, 2008 Author Report Posted February 4, 2008 Just cause It runs good, doesn't mean its running the best it can. We do alot of dyno testing, and a good majority of the bikes out there with 35mm pwk's are way over carbed. I have seen cases were when the carbs were sized down 7mm to a set of 28's, it picked up2-3 midrange hp and the topend stayed the same. Im using slightly modified 28mm flatslides now and it runs like a beast. I dont know much about the 2 into 1`s and thought Id ask, a guy here locally had one with a 39 on it for $150. I might just go with a 35, or a pair of 30`s then. Slightly larger carbs flow more air, but flow velocity and atomization are better with a little smaller IMO. I read alot on the 35`s for the 2 into one, but didnt see anything on slightly larger displacements. Quote
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