b40rt Posted June 22, 2013 Report Share Posted June 22, 2013 Can an old engine develop more power ? I put a new to me Rotax 240 engine into a SWM several months ago, it ran OK. I haven't changed the timing or carb, but have repacked the middle box and changed the back box. The increase in power wasn't instant, just a gradual improvement. The previous exhaust wasn't full of oil etc. One suggestion is the disc valve is sealing better ? Any thoughts or am I just imagining it ? Quote Link to comment Share on other sites More sharing options...
feetupfun Posted June 22, 2013 Report Share Posted June 22, 2013 stuck rings can free up with use Quote Link to comment Share on other sites More sharing options...
steveo Posted June 22, 2013 Report Share Posted June 22, 2013 Have you lost some weight recently......... 1 Quote Link to comment Share on other sites More sharing options...
b40rt Posted June 22, 2013 Author Report Share Posted June 22, 2013 stuck rings can free up with use I wondered about that, but would it be gradual ? Have you lost some weight recently......... Hair doesn't weigh that much !! Quote Link to comment Share on other sites More sharing options...
feetupfun Posted June 22, 2013 Report Share Posted June 22, 2013 I'm just theorising here but if they had been stuck for a while, maybe they didn't seal too well to start with then improved as they bedded in When I have had them unstick, it has been the result of getting the motor much hotter than normal for a brief period, and I noticed the improvement in performance pretty much as soon as the motor was back to normal temperature, and so was able to identify the cause of the performance improvement 1 Quote Link to comment Share on other sites More sharing options...
pschrauber Posted June 22, 2013 Report Share Posted June 22, 2013 (edited) A fresh repacked exhaust will improve the flush of a two stroke engine. The SWM doesn't have a diffusor like. My 2-stroke KTM from 1989 run much better which a repacked mid and end section. The effect might not be very much but its quite remarkable. A sticky piston ring that have come loose might also have been the case, I have heard about but never heard from anybody that have found them beside in old barn finds, but why not, sounds like a good exploration. It could as a guess also have been a tiny piece or fibers of a cleaning rag which stuck somewhere in the carburetor and is now flushed away. when something suddenly runs better then before there was mostly a fail that got fixed by itself ... Edited June 22, 2013 by pschrauber Quote Link to comment Share on other sites More sharing options...
nelly1 Posted June 22, 2013 Report Share Posted June 22, 2013 do you think you may be running too much oil in the fuel you get it hot it clears and runs better just a thought Quote Link to comment Share on other sites More sharing options...
t-shock 250 Posted June 22, 2013 Report Share Posted June 22, 2013 If you ditch the original tailpipe & fit a WES or similar style alloy one, you will see even more performance gain. 1 Quote Link to comment Share on other sites More sharing options...
b40rt Posted June 23, 2013 Author Report Share Posted June 23, 2013 do you think you may be running too much oil in the fuel you get it hot it clears and runs better just a thought Always run it at 50:1 fully synthetic, the performance seems to have gradually improved. If you ditch the original tailpipe & fit a WES or similar style alloy one, you will see even more performance gain. Any particular model you can recommend ? Quote Link to comment Share on other sites More sharing options...
pschrauber Posted June 23, 2013 Report Share Posted June 23, 2013 May be a bit stretchy what about timing. The timing of the ignition could have been changed and was not perfect adjusted when you got the engine? With a bigger gap between the points due to wear you might now have the right timing? This would be an explanation for the better power delivery. BTW.: I have ridden once the 240cc bike and in this short experience with the ride I recognized that the 240cc engine is a little bit more lively then the 280 in low to mid revs, (it was a short ride). Quote Link to comment Share on other sites More sharing options...
b40rt Posted June 23, 2013 Author Report Share Posted June 23, 2013 Hi Patrik, I like the 240 alot, nice and lively as you say, but this one has alot less flywheel weight than your 280. 1 Quote Link to comment Share on other sites More sharing options...
pschrauber Posted June 29, 2013 Report Share Posted June 29, 2013 The lighter flywheel sounds too, truly will eliminate the little break you have when picking up rev. but too will reduce the "rubber band" effect the engine have which I now after 1'5 years of riding with the bike like more and more. My be I'am getting old style ??? Quote Link to comment Share on other sites More sharing options...
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