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performance notes
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==QT Performance==
 
==QT Performance==
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In stock configuration, the QT50 will hit about 29-30 mph.  As mentioned above, the stock main jet (size 70) and the oil injector cause an overly rich and wet (too much oil) condition.  Many QT50 owners initially cannot get past 25 mph or so because of the resultant four-stroking.  Many attribute this wall to some sort of rev limiter.  No such rev limiter exists.  Your QT50 is just getting too much gas and oil.  This does not mean that all four stroking is bad.  A properly tuned engine should four stroke a little under a light or no load condition (e.g., going downhill).  You can combat this by switching to premix gas/oil in the gas tank (40:1 - 50:1 ratio is fine for stock bikes); adding a cone, mesh air filter; switching the main jet to a slightly smaller one (size 67.5); or combination thereof.  Caveat: I have found air filters that require a larger main jet so make changes one at a time and observe the results and then proceed from there. 
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Performance upgrades, as listed above, exist for the qt50 that will make 50 mph~ attainable.  The lesson of mopeds and nopeds is to find your next bottleneck and fix it.  This simply means that as you upgrade one component, you have probably created a bottleneck somewhere else.  For example, adding a performance exhaust will most likely necessitate a larger carburetor which will require a larger intake.  Or adding a bigger top end will require other modifications in order to achieve the potential of the new top end.  Focus on the system as a whole.  A temperature gauge is your best friend on your quest for better performance.           
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[[qt performance]]
 
[[qt performance]]
  
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