KDXRIDER.NET

Okay so I got this bucket of a bike, it is a 1977 XL75 frame with a Frankenstein 1984 XR80 motor in it. The boy I bought it from, for like 200 bucks, stated that he couldn't get the bike to run. He said when he first got it, it ran fine, when he sold it to me it was not functional. He also stated that he redid the top end, which I'm assuming is true, the bike has good compression. He thought it might be something with the wiring which could be true, its very.... sketchy. The kill switch had been cut, the wire leading to the motor had been cut and crimped, the wiring from the coil had been crimped too. I tried to fix what he had done, I soldered the cut ends from the coil pack back together, wired in a kill switch. But it wouldn't run. I got the new correct spark plugs for it and used the original carb. Couple of kicks and it started right up. But things were not good for long. It would start revving randomly and couldn't hold idle, there was no adjusting the carb either, I adjusted every screw in that damn thing and it wouldn't do a thing. So I bought a new carb and slapped her in there, went to kick it and now I don't have spark! I have no idea where to start from here. I thought I'd come here for some help see what the rest of you can offer me in terms of advise.

check for battery voltage. I think those old bikes used the battery as part of the ignition system.

First thing to check on pre-91 XR80/100s without spark is the condition of the breaker points. They didn't switch to electronic ignition until pretty late in the game on those, and breaker points are susceptible to spark-killing oxidation when left sitting.

Jaguar wrote:check for battery voltage. I think those old bikes used the battery as part of the ignition system.

The guy who had it before me took all that wiring and stuff off, so no headlights taillights or battery.

sarrant wrote:First thing to check on pre-91 XR80/100s without spark is the condition of the breaker points. They didn't switch to electronic ignition until pretty late in the game on those, and breaker points are susceptible to spark-killing oxidation when left sitting.

I have no idea where that is located? Is it near the fly wheel? No very familiar with 4 strokes.

It isn't a really a 4-stroke thing. Older 2-strokes have breaker point ignitions as well.

The points are located on the stator plate behind the flywheel. There is a hole in the flywheel through which you can see if they are firing when kicking it over. Usually you can cut a strip of cardstock/sandpaper and slide it between the points, then hit them with some spray cleaner to get them going quickly.

Otherwise, you'll want to look up the maintenance/gapping/replacement procedure.

It can also be converted to electronic ignition with a kit or the ignition components from a 92+ engine.

sarrant wrote:

The points are located on the stator plate behind the flywheel. There is a hole in the flywheel through which you can see if they are firing when kicking it over. Usually you can cut a strip of cardstock/sandpaper and slide it between the points, then hit them with some spray cleaner to get them going quickly.

Would it be worth it to just buy new points? I appreciate the advise, if this doesn't work I don't know what it could be.

It will take you all of five minutes to pull the cover run a piece of cardstock/folded paper/sandpaper between them, to see if they start firing.

But sure, you can replace them if they need it.

I still have the first dirtbike I ever owned, a 1980 XR80. I'll second the recommendation on cleaning the points. That would be the very first thing to check.

Okay thank you both for the advice, and I just now realized I've been spelling that wrong this whole time. I will clean them as soon as possible and let you know how it goes!

Okay well I cleaned the points (scraped between them with some sand paper) and went to kick it over and nothing happened. No spark still.