J-Madd Posted September 12, 2007 Report Posted September 12, 2007 I already have the powerjets, needles and billet bowls for these carbs. I also have another motor on alcohol with 39 mm carbs that Jeff set up. It looks like all you have to do is drill/tap a hole for the power jets and barb on the bottom of the bowl. I already know how to drill the dump tube and main jets. Is it that simple? Oh yeah, and what size bit and tap......... Thanks. Quote
dajogejr Posted September 12, 2007 Report Posted September 12, 2007 Larger pilot, drill the dump, drill a few main ranging in size from the same as the dump to .001 to .005 smaller...drill the bell and epoxy/JBWeld the power jet in place. Since you have oversized bowls, there is no overflow tube...just use the barb on that. Measure the diameter of the PJ where it will mount on the carb, used that size drill...you want a tight fit. I couldn't tell you what size mains/dumps to use without knowing what kind of motor, etc. Remember, you can always drill the dump tube bigger, but it can't be replaced. Too big...and the carb is trashed for your use... Quote
J-Madd Posted September 12, 2007 Author Report Posted September 12, 2007 Larger pilot, drill the dump, drill a few main ranging in size from the same as the dump to .001 to .005 smaller...drill the bell and epoxy/JBWeld the power jet in place. Since you have oversized bowls, there is no overflow tube...just use the barb on that. Measure the diameter of the PJ where it will mount on the carb, used that size drill...you want a tight fit. I couldn't tell you what size mains/dumps to use without knowing what kind of motor, etc. Remember, you can always drill the dump tube bigger, but it can't be replaced. Too big...and the carb is trashed for your use... Motor is stock stroke 68mm Cub, Shearer inframes or outframes or CPI inframes, whichever I decide to run on it. I'll be using EGN needles. Quote
dajogejr Posted September 12, 2007 Report Posted September 12, 2007 I think you'll be ok with .120 dumps, .118 mains and 52 or 55 pilots. Powerjets all the way out for starters. That's a guess....but should be safe... By the way, do you know what your squish and compression ratio is at? As well as timing, what is it?? Quote
J-Madd Posted September 12, 2007 Author Report Posted September 12, 2007 Compression was 160 psi (top end is apart right now), not sure about squish on this motor; Jeff put it together himself and I'm sure he checked it. Timing is at +9. Quote
dajogejr Posted September 12, 2007 Report Posted September 12, 2007 Ahh...got it. Might be best to check with him on jetting...he knows what his motors like for fuel better than anyone... Quote
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