Changes

48 bytes added ,  13:41, 6 January 2018
m
minor changes
Line 18: Line 18:  
Controlling the heat produced by a bigger top end and/or a performance exhaust is a common issue with QT50s.  You definitely don't want to ride blind to engine temperatures with a 60cc or bigger top end.  A temperature gauge is mission critical to keeping your piston from soft seizing.  Consider it a $39 insurance policy.  Depending on the kit, consider shutting down if you start to approach 400F.  Maybe sooner if you want to be more cautious.  Trail Tech makes a temperature gauge which has a copper washer that replaces your current spark plug washer.   
 
Controlling the heat produced by a bigger top end and/or a performance exhaust is a common issue with QT50s.  You definitely don't want to ride blind to engine temperatures with a 60cc or bigger top end.  A temperature gauge is mission critical to keeping your piston from soft seizing.  Consider it a $39 insurance policy.  Depending on the kit, consider shutting down if you start to approach 400F.  Maybe sooner if you want to be more cautious.  Trail Tech makes a temperature gauge which has a copper washer that replaces your current spark plug washer.   
   −
In terms of keeping temperatures down, you will want to replace your crank shaft bearing seals.  Proper jetting of the carburetor (main jet, jet needle, and idle jet) are critical to keeping temperatures in a manageable range.  The main jet should be your initial focus.  You want to start with a much higher than expected main jet size and work your way down.  Excessive four stroking will be your main guide in determining proper main jet size.  The temperature gauge will be your other.  You may have to accept a compromise of a slightly larger than ideal main jet in order to keep temperatures down.   
+
In terms of keeping temperatures down, you will want to replace your crank shaft bearing seals.  Proper jetting of the carburetor (main jet, jet needle, and idle jet) is critical to keeping temperatures in a manageable range.  The main jet should be your initial focus.  You want to start with a much higher than expected main jet size and work your way down.  Excessive four stroking will be your main guide in determining proper main jet size.  The temperature gauge will be your other.  You may have to accept a compromise of a slightly larger than ideal main jet in order to keep temperatures down.  After the main jet, dial in the jet needle.   
   −
Another strategy is to employ a colder spark plug.  Stock plug is an NGK BP4HS.  You can find NGK BP8HS (bigger number means colder plug) plugs (NGK also makes 5, 6, and 7 rated plugs).  I've found 9 and 10 plugs in the NGK BPS plugs (a shorter plug run with the Malossi kit).   
+
Another cooling strategy is to employ a colder spark plug.  Stock plug is an NGK BP4HS.  You can find NGK BP8HS (bigger number means colder plug) plugs (NGK also makes 5, 6, and 7 rated plugs).  I've found 9 and 10 plugs in the NGK BPS plugs (a shorter plug run with the Malossi kit).   
    
Other cooling methods include running a thicker head gasket (or more than one head gasket) to reduce compression (you can also reduce compression by increasing cylinder head chamber size) and running a Jog cdi with a curve that allegedly retards timing at higher rpms.  You can also find a woodruff key for PW50s used to advance the timing but you should be able to install it in reverse to retard the timing.  Of course, this would retard the timing at all rpms and may not be ideal.  A bigger cylinder head would also help with cooling.  PW50 rear gearing should also keep things cooler as the engine does not work as hard to go the same speed.   
 
Other cooling methods include running a thicker head gasket (or more than one head gasket) to reduce compression (you can also reduce compression by increasing cylinder head chamber size) and running a Jog cdi with a curve that allegedly retards timing at higher rpms.  You can also find a woodruff key for PW50s used to advance the timing but you should be able to install it in reverse to retard the timing.  Of course, this would retard the timing at all rpms and may not be ideal.  A bigger cylinder head would also help with cooling.  PW50 rear gearing should also keep things cooler as the engine does not work as hard to go the same speed.   
   −
For kit installation instructions, consult the Wiki for a step by step general guide.
+
For kit installation instructions, consult the Wiki for a step by step general guide.
 
  −
 
      
==Links to good articles==
 
==Links to good articles==
39

edits