Hi everyone, I've had some problems with a '77 El Tigre I picked up 3 years ago and never got around to figuring the problem out. This will be a little lengthy, because I want to cover all troubleshooting so that it will possibly help you guys narrow down what I need to look at.
The sled starts up fine, and when I've taken it out for a ride it seems to be OK until it has been ridden for a couple of minutes, or has warmed up. It will slowly die out or bog to a stop and then cut off. Sometimes I'm lucky enough to get it back up and running a few seconds later and get a few more seconds of riding out of it, when other times I have to wait 5-10 minutes for it to want to start back up and run until it does the same thing again.
It has always seemed that packing the heads with snow seems to get it to start back up sooner after it gets to the point where it cuts out and won't immediately start back up. If I pack the heads with snow for a few minutes, it fires back up much sooner than just waiting it out.
The top-end was supposedly recently rebuilt when I got it. I have thoroughly cleaned the carbs numerous
times and have visually synchronized the carbs the best I can. It has had fresh gas in it (mixed with a little more oil than the original owner's manual recommended) and I have sprayed WD-40 around the crank seal while it was running and did not experience it revving up any higher on its own.
I shot this video last winter when the problem seemed to get worse. It got to the point where I can do a cold-start on it and it won't stay running for long at all, and at the end of the video it got to the point where it would not start back up at all (I tried plenty more times after I stopped recording).
The only things that come to mind is maybe the CDI, or the fact that the sled does not have an airbox. I bought the sled without the airbox (didn't even realize it was missing when i bought it) and the previous owner made no mention of it missing the airbox, and claimed it was running great when I asked him general questions about the sled the day I went to buy it. But I'm wondering if maybe the carbs still have the factory jets, and having no airbox is leaning out the mixture too much.... but at the same time I don't think that scenario would cause the engine to not want to start back up for several minutes after it dies out.
A buddy of mine suggested that maybe the CDI is fine until it gets a little warm, and then an internal circuit is opening at that point due to the CDI possibly going bad. That sounds logical. I can't tell if it's the factory CDI or if it is a replacement. This reminds me, though-- I have a spark tester (plugs in between the sparg plug and the plug boot) and if I recall correctly I think I tested the sled with it at one point and it was still getting spark when I tried spnning the engine over after it would not start. I might be wrong on that though, I'll try that tonight to see.
Any other suggestions in the meantime??? Thanks a bunch!