As you can see I am new here. Although I am pretty good with old hotrods, my son has an 01 Blaster that seems to be giving me some problems. My brother in law is excellent with 4 strokes but like I he is stumped on this 2 stroke prob. I have checked the other posts here but none address my same problem.
Heres the quad specs.
01 Blaster, has new .80 over piston, cylinder/head were bored/honed/surfaced, Aftermarket exhaust (BG I think), K&N filter, not sure about aftermarket reeds or carb mods, No longer oil injected (mixed fuel), has aluminum Raptor wheels/tires, with nerf bars, pictured on my profile,
Motor History: Motor was built about a year ago by my Brother in law, this was due to a hole in the piston most likely due to my use of the wrong fuel can (now all are correctly marked), in which unmixed fuel was run and caused meltdown to piston, Piston replaced, cylinder was machined .060 and inspected for damage along with head (but not surfaced this time).
Motor put together and ran well for several months of use, then motor problems again, did a compression test (60 psi), once apart it was found that we had a blown head gasket due to head bolts pulling the old/used threads out (yes they were torqued correctly) that caused a lean condition and started melting piston but caught early, Had cylinder machined/bored/honed .080 over, head surfaced, new piston/rings/bearing/spark plug/clips/gaskets, all bolt holes helicoiled put back together and torqued.
Problem: Once everything was back together, we went through a couple of warm up and cool down break ins, after that we checked/tunned for air/fuel mixture, once that was done he took it for a couple of partial throttle runs with cool downs in between. Once this was done there were a couple of 1/2 throttle runs and noticed a slight bog or power loss about 1/2 throttle, After that we took a run and shut the engine off with it at about 2/3 throttle. Looking at the spark plug showed what appears to be a lean condition (very light grey/white on the spark plug tip). We checked the compression to find we have 87 psi. Reeds do need replaced but not in to bad condition. Carb adjustment appears to be Ok, idles excellent with a slight blue haze, mixture is good which has now been perfected if theres a such thing. All top end is new!!
In a nut shell we have 87psi compression and a power loss above 1/2 throttle. Anyone have any suggestions? Is there anything in the bottom end that could cause issues (cracked case, etc...)? What should my compression be at (Comp tester with valve used)? Please help before my 12 yr old drives me crazy due to with drawls. Thanks! Jay -generalsnbandit
Heres the quad specs.
01 Blaster, has new .80 over piston, cylinder/head were bored/honed/surfaced, Aftermarket exhaust (BG I think), K&N filter, not sure about aftermarket reeds or carb mods, No longer oil injected (mixed fuel), has aluminum Raptor wheels/tires, with nerf bars, pictured on my profile,
Motor History: Motor was built about a year ago by my Brother in law, this was due to a hole in the piston most likely due to my use of the wrong fuel can (now all are correctly marked), in which unmixed fuel was run and caused meltdown to piston, Piston replaced, cylinder was machined .060 and inspected for damage along with head (but not surfaced this time).
Motor put together and ran well for several months of use, then motor problems again, did a compression test (60 psi), once apart it was found that we had a blown head gasket due to head bolts pulling the old/used threads out (yes they were torqued correctly) that caused a lean condition and started melting piston but caught early, Had cylinder machined/bored/honed .080 over, head surfaced, new piston/rings/bearing/spark plug/clips/gaskets, all bolt holes helicoiled put back together and torqued.
Problem: Once everything was back together, we went through a couple of warm up and cool down break ins, after that we checked/tunned for air/fuel mixture, once that was done he took it for a couple of partial throttle runs with cool downs in between. Once this was done there were a couple of 1/2 throttle runs and noticed a slight bog or power loss about 1/2 throttle, After that we took a run and shut the engine off with it at about 2/3 throttle. Looking at the spark plug showed what appears to be a lean condition (very light grey/white on the spark plug tip). We checked the compression to find we have 87 psi. Reeds do need replaced but not in to bad condition. Carb adjustment appears to be Ok, idles excellent with a slight blue haze, mixture is good which has now been perfected if theres a such thing. All top end is new!!
In a nut shell we have 87psi compression and a power loss above 1/2 throttle. Anyone have any suggestions? Is there anything in the bottom end that could cause issues (cracked case, etc...)? What should my compression be at (Comp tester with valve used)? Please help before my 12 yr old drives me crazy due to with drawls. Thanks! Jay -generalsnbandit
