Probably ruined my new 78 Pinto, but in what way...?

Julian Rojas /
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Hey guys.

I haven't been to these forums in almost 10 years. I gave up the hobby for a while, but I just moved to sacramento and I needed an easy, reliable (ha!) way to get around, saw the bike on Craigslist, and bit the bullet - bought a 78 JC penny pinto II, and had the poor thing running like a dream for about a day.

When I went to pick it up, I filled it up with two quarts of premix on the spot. It ran great, idled great, thing looked fine, price seemed reasonable. I bought it, drove it to my brother's house about 6 miles away, hung out for the night, then set out in the morning to drive the 13 or so miles back to downtown Sacramento. I started to run out of gas on the way back - or maybe I just thought I was, maybe it was just stalling for a different reason, but - I figured, I remember how to do this, I'll just gas up and get back on the road. So I pull into the gas station, grab some oil, and then quickly google what octane gas I should use in the bike. First result says Premium, I barely skim through it, figure I'm fine. I fill the thing up with a gallon of premium, toss a couple of capfulls of oil into the tank, shake it up a bit, and get back on the road.

Obviously I made it like, 15 more minutes down the road - and that was probably only because It was burning through the rest of the premix - before the bike gave up the ghost. It was right when the thing was starting to run it's fastest too, it was going about 45 - so I imagine the thing was heating up pretty good thanks to the premium fuel, on top of being starved of oil.

Thing is, I'm not sure what happened. I thought I seized the engine at first, but, having pedaled it back to my brother's garage and poked at the thing, it seems like piston's moving perfectly, and from a cursory thumb check, the engine seems to have ok compression. I haven't pulled the whole thing apart yet, because I'm real rusty when it comes to this stuff, but having heard what a fucked up engine sounds like on one of these, compared to what I'm seeing - I think it's still OK.

So then I started to think maybe I was lucky enough with the amount of premix I had and the amount of oil I mixed that the thing wasn't running dry, and that wasn't my issue, maybe it was an electrical issue. So I checked, the spark plug was rusted all to hell but I replaced it and checked the electical and it all seems A'OK. It's sparking fine, and I don't think the timing suddenly got fucked up while I was driving it so fast, but I don't know.

The carburetor seems clean and functional, too - though it looks like the one I had on my old Garelli, and not at all like the one on any others I've seen online for this bike.

Also the thing's got no air filter at all - just a bit of stocking over the hole. But that's how my old one was too, if I recall, and that wasn't much of a problem.

so, I figured maybe the premium fuel just overheated it, and it blew a gasket on the engine from getting too hot and now all I'm getting is because I've got low compression? but it should still be turning over occasionally, if that were the case, right? the lights will flicker on when I pedal like a madman but the thing just doesn't even begin to fire up.

I don't know, this thing was regularly maintained by it's previous owner - it was mint and great and I just feel like such a fool having been so cavalier with it right after I got it. I haven't messed with one of these things in so long, and while it's been fun to take it apart and poke at it a bit this evening, It was perfect yesterday and now it's another project bike. I don't think I've done too much damage, I'm sure I can fix whatever issue this is OK, but.... I'm gonna need some help. Any advice?


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