|
|
Post by Brian OKeeffe on Sept 12, 2006 15:07:07 GMT -5
I have a GY6 equipped quad here that seems to have developed a ping when the engine is under a load. Plug appears normal with no evidence if detonation, but the ping is very evident at full throttle under load. I am at 3500' with stock jets and an open/non baffled exhaust. Stock CDI as well. The motor is about 2 years old now with good compression.
|
|
|
|
Post by Brian OKeeffe on Sept 12, 2006 15:09:25 GMT -5
Added a bit of "octane boost" to the tank with no affect.
|
|
|
|
Post by woodlark on Sept 12, 2006 15:40:24 GMT -5
If you are at 3500 ft, have stock jets and an open exhaust, chances are that motor is running extremely lean. You need to at least adjust the mixture to make it richer, and you may need to install larger jets.
|
|
|
|
Post by jackthefuzz on Sept 12, 2006 16:54:05 GMT -5
actually you need to lean it at altitude. less air needs less fuel. taking into account that you are running with little or no exhaust back pressure and most probably with the mixture on the rich side, my bet would be on carbon forming in the combustion chamber creating hot spots thats pre igniting the mixture. only way to tell for sure is removing the head. One way to gradually reduce that problem and clean out the carbon is to mix some marvel mystery oil in with the gas. a fast way of removing carbon is go to a outboard motor retailer and get a can of fogging fluid. this is the fluid thats sparyed in the carb on an outboard to winterize it. this will remove carbon real fast. start up the quad run it enough to bring the engine up to full temperature and spray the fogging fluid into the carb while the engine is running. you will want to make sure the wheels are of the grund as you are going to want to rev the engine while youa re doing this. then when the can is almost empty, bring the engine to idle and spray the rest in the carb untill the engine dies. let it cool off, change the plug and fire it up. guaranteed the combustion chamber will be clean
|
|
|
|
Post by jackthefuzz on Sept 12, 2006 16:57:49 GMT -5
oh and btw if youa re going to do that make sure the exhaust is pointed at something you dont care about because a bunch of crud is going to come out of the tailpipe and carbon is a real bugger to clean up
|
|
|
|
Post by woodlark on Sept 12, 2006 18:13:05 GMT -5
jack,
I stand corrected. you're right, I was thinking backwards (time out for a senior moment)!
|
|
|
|
Post by russ553 on Sept 12, 2006 20:19:09 GMT -5
Woodlark,
I think that stuff we seniors have is called halfzheimers. We can still remember we forgot something! Happens to me all the time.
|
|
|
|
Post by liverchip on Oct 3, 2006 20:53:13 GMT -5
The engine ping has been solved. Turns out that the crankcase vent line was venting hot gas under the carb. I have relocated the line to the frame under the cylinder as is the vent on my old VW. CA smog laws be damned. My theory is that the hot gas was heating the carb and possibly vaporising the gas in the internal passageways causing the mixture to lean out. With the vent line relocated, no more ping.  |
|
|
|
Post by jackthefuzz on Oct 3, 2006 21:11:41 GMT -5
The engine ping has been solved. Turns out that the crankcase vent line was venting hot gas under the carb. I have relocated the line to the frame under the cylinder as is the vent on my old VW. CA smog laws be damned. My theory is that the hot gas was heating the carb and possibly vaporising the gas in the internal passageways causing the mixture to lean out. With the vent line relocated, no more ping. GOOD FIND!!!! |
|
