January 19, 201214 yr any ideas on how the scavenge pipe from the crank case is suposed to work? runs great disconnected with a little air escaping from crankcase breather, connect it to carb and the bike runs as if the choke is on. conection to carb is clear. is it building up pressure in the carb? should the pipe have air puffing out of the crankcase breather cheers guys for any info
January 19, 201214 yr Author any ideas on how the scavenge pipe from the crank case is suposed to work? runs great disconnected with a little air escaping from crankcase breather, connect it to carb and the bike runs as if the choke is on. conection to carb is clear. is it building up pressure in the carb? should the pipe have air puffing out of the crankcase breather cheers guys for any info just had another look at it and the breather from the crankcase has a suck and blow effect coming from the pipe. block the pipe and bike runs ok ,just have to turn the tickover up a bit, connect pipe back to carb and straight away runs like on choke.
January 19, 201214 yr IF YOU'VE GOT ROTAX ENGINED APRILIA THE PIPE ORIGINALLY HAD 1 WAY VALVE BETWEEN ENG. + CARB .IDEA WAS EXCESS/UNBURNT FUEL PUSHED BACK INTO CARB BY ENGINE COMPRESSION HELPING BIKE TO RUN CLEANER + PICK UP BETTER FROM IDLE
January 19, 201214 yr Author IF YOU'VE GOT ROTAX ENGINED APRILIA THE PIPE ORIGINALLY HAD 1 WAY VALVE BETWEEN ENG. + CARB .IDEA WAS EXCESS/UNBURNT FUEL PUSHED BACK INTO CARB BY ENGINE COMPRESSION HELPING BIKE TO RUN CLEANER + PICK UP BETTER FROM IDLE cheers fot that scratt , makes a lot of sense as to whats going on
January 19, 201214 yr If i remember correctly, we disconnected the scavenge valve & blanked it off. I didn't like the idea of fuel (or more likely, oil that gathers in the bottom) being fed back to the carb. The best mod though was to raise the barrel 2 or 3mm, on the 240 engine this allowed the exhaust port to be fully uncovered, the bike revved much better after this.
January 28, 201313 yr Author hi t shock regarding the mod lifting the barrel 2mm, have had a look at mine and sure enough the piston covers the port by approx 2mm, after rasing the barrel is it nessasary to remove material from the top of the barrel to maintain the same compression
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