Gordon, there are several small tricks to improve the power of the motor so you don't have to revert to a lower ratio.
1) jet the carb (typically leaner) with different jets and needle position. Read up on "Plug Chop".
2) Cut a squish band on your head out to bore diameter (40/47mm), then set the squish gap t 0.030" with gaskets
3) portmatch the exhaust pipe flange and gasket with a 3/4" drill
These 3 "tricks" will gain plenty of power for the hills.
Steve
GO TO
Lynn@CustomMotoredBicycles.com
They have 32-36-38-39-40-44-48-50-52-54-58-60-62 tooth sprockets in all bolt patterns and steel and aluminum, flat or dished, thick or thin, and 410 and 415 chain,,,great selection,,
but something is power robbing your bike,, i have a 44 tooth and gain speed on hills and 38mph on flats,,, i never peddle even taking off on hills
listen to Steve he is brilliant ant wont give you bull crap,,
did you ever take your cylinder off and clean all casting imperfections and lips on transfer ports,, plus widen the exhaust port 2mm on each side and 2mm off the top, intake you can widen a hair on each side ( watch your rings on piston they dont catch in port opening))) and put your cylinder on and look thru intake port while the piston is at top dead center( as far up as it can go)) look in your intake port and with a marker color in part of piston skirt that you see, remove cylinder and piston and Ddremel gring out the marker section,, also you can double your base gasket and while your down there put PLAY-DOUGH clay all down in case so nothing can get in,, now place your bas gasket on bottom of cylinder,,
do you see all that over lapping gasket does,, well trim it with exacto knife to fit and line up perfect,, now take gasket and place on the case as if you were installing,,take a thin marker and color in all metal on the inside of gasket,, with play dough firmily in there pressed every ware tight,, tremel that extra metal at a 45*degree angle,, you just want to bevel it so there is an even flow with no hang ups into transfer ports,, and port match you exhaust outlet to your exhaust opening by gringing exhaust pipe mounting flange to shape of exhaust port,,, watch you dont go thru welds in pipe flange
doing all this will take some time and make yo feel like a dentist,, but like steve said your engine will increase a lot in power and revs,,,take your time and make shure you go into cylinder and chamfer all edges at an angle so your rings dont snag on them
get some micro drills sizes .060--.080 and solder, take your main jet out of carb and put a very,very,very small tip,bit of solder on it,,, hold over candle till it melts,,, take micro drills start with.065 and drill thru solder in main jet,, instal,, adjust float height to 22mm,, put black e-clip in top slot on needle... if you are two lean after it fully warms up,, re drill main jet up to .067 and keep repeating this process till it runs good
need any help doing this PM me,, or ask Steve if he will help you,, he is amazing at this stuff