DT65 drops ignition on one cylinder

[Sarrre]

Hi,
I have a problem with a DT65 from 1988 that is having an ignition issue. The engine will not rev up. I was checking all cylinders with a timing light and found out that the bottom cylinder misses sparks when reving up. At idle speed there is always ignition. I tried to switch coils, but the problem remains on the same cylinder. Could it be the CDI box? Trigger? Something else?

[mphelle8vld]

Could be in limp mode which would cut a cylinder and limit rpm to around 3000. Do you have a functioning monitor gauge installed?

[Sarrre]

No I don't have any gauge installed, but it only runs in idle speed. It will run like crap as soon as I increase the throtthle. It is sooner than 3000 rpm.

[Solarman]

It could be that spark plug, that cylinders coil, then the next check would be the gear counting coil, next is that cylinders pulser coil, then maybe the throttle valve switch, and last would be the CDI.

You did use a timing light, and said #3 cylinder was missing spark. The gear counting coil (rpm of flywheel) and the throttle valve switch (position of throttle) control timing, with the CDI. But the #3 pulser coil with the flywheel magnet sends the signal to fire #3 plug/coil.

The Suzuki service manual for your year/model DT 65 should tell you how to test the items listed above.

It is also important to know that with a 1988 motor many parts are no longer available?

I should also mention that wiring connections for each of these items listed are very important. Any corrosion, grounded/loose/poor connections of wires can cause these problems.

Good luck, post back if you find what's causing your problems.