Hello again Last week I posted that I thought my 2006 Hemsin 250 Tierra had jumped time because it really kicks back hard we cleaned the carb and checked the intake boot for leaks changed the plug So I checked the line up marks on the cam and crank Checked valves everything is good and like new but when you lay the plug out on the head and pull it over instead of spark on and off on the electrode gap it is a steady arc as long as the motor is spinning and you can actually hear it buzzing like an arc welder buzz I Have never seen anything like this ,, Also I traced the wires back to the mag/stator and the outside pick up on the outside of the flywheel [sorry I don't know what it's called] the small black box with two wires the I assume times the spark,,, It has this spark whether its plugged into the cdi or not is this possible ??? I actually Called a buddy who is a mechanic and asked him about this he came over and said he's never seen spark like this we took the mag and stator out and checked to see if any of the wires were bear and croos but they look fine now the quad idles pretty good but when you give it gas it boggs and has no power So please If you have any ideas on what could be happening here PLEASE let me know Thanks

 

<div class="FTQUOTE"><begin quote>Originally posted by: junkorama
...I traced the wires back to the mag/stator and the outside pick up on the outside of the flywheel [sorry I don't know what it's called] the small black box with two wires the I assume times the spark,,, It has this spark whether its plugged into the cdi or not is this possible ???</end quote></div>

The CDI should not fire (and no spark should be generated) with the timing pickup trigger wire disconnected. Therefore if what you say is correct then the CDI is bad.

This is a really weird problem. Especially so since it idles. How can it idle with a constant spark? My guess is that it isn't sparking continuously when it is idling. This is kind of backed up by your statement that is pulls over fine sometimes and almost breaks your arm others. I think your quad is on the verge of working/not working at idle speeds. And it doesn't work at all at higher speeds.

The two inputs to the CDI are Power and Timing/Trigger. The power is high voltage AC coming from a coil in the stator. The amplitude of the voltage generated on the power winding is directly proportional with engine speed, and ranges from 80 Volts AC at cranking speeds to over 300 volts at high RPM. All this winding is used for is charging up a large high voltage capacitor which gets dumped onto the coil primary at the proper time as triggerd by the timing/trigger winding. I'm guessing that the CDI is breaking down internally at higher voltages (i.e. higher RPM) and firing the SCR (transistor switch) which generates the spark without the proper trigger pulse (and of course bogging down the engine because it isn't at the appropriate time).

Your said in an earlier post that the CDI had been changed. Perhaps there is more than one problem now. The CDI was changed, which didn't fix the original problem, and added another. Two problems at once is ten times harder to fix than solving one at a time.

CDI's can be found on eBay for around $10.00 including shipping.

Please let us know how this turns out. I'm very curious about this.

Lynn Edwards

 

It's all the Chinese lead paint falling off causing a lectrical spasm...LMAO..
Sorry, just had to. [img]i/expressions/face-icon-small-happy.gif[/img]