1987 Suzuki Quad Runner 250 4x4 blown engine - what to do?
I have a 1987 Suzuki Quad Runner 250 4x4 that appears to have just blown its engine. I picked up this unit as a beater and the engine and drivetrain seemed solid. The charging/starting system wasn't perfect but it would run.
It began running rough and I tried several things including fuel system cleaner to get it running better. It finally quit running and I realized it had no compression. I thought it was a stuck valve but figured out the lash adjustment was set WAY too far in so the intake valve wasn't closing all the way. I adjusted this out to spec and it would start and run again, although not well. I rode it for a few more days and the same thing happened. No compression and it wouldn't run. Again, the valve lash was way in on the intake so it wouldn't close. I adjusted and got it running once again. I tigtened the jam nuts so I don't know why this was happening. Also, shouldn't valve lash adjust itself the other direction as things loosen up?
I looked like the top end was getting plenty of oil as I fired the engine up for a second with the valve cover caps off to make sure I had done it right and quite a bit of oil came out both times. I was ready the second time and had a pan underneath. I made sure to replace any lost oil which could have been more than a couple ounces before starting again.
I changed the oil and filter when I first got the unit with normal conventional. It didn't look like the oil changes had been done with great regularity but I have certainly seen worse oil in the past. I changed once more with the same oil (kept same filter), and then again once the hot weather hit to Mobil 1 synthetic (changed filter).
I appear to have just had a pretty catastrophic failure but want to check before doing anything. I was riding and the engine was running rough as though there was a lot of internal resistance. I didn't know what was going on but I kept it pretty gassed riding back to my place. It died a few hundred feet from the house with a machine gun type rattle for a second or so after it quit. I immediately was worried it had thrown a rod and then noticed some oil dripping out of the bottom.
I drained the oil at this point and noticed that it wasn't low when this happened so it hadn't been run too low on oil. I have a couple questions?
1. Is this even worth repairing? If so, what parts will I all need? I assume this is going to require a cylinder or sleeve, piston/rings, connecting rod, at least one side of the engine case, and crankshaft.
2. If the answer (1) is no, which I suspect is the case, how is the best way to recoup the money I have in this machine?
A. Sell the entire unit on eBay as a parts unit. The 4WD seems fine and it shifted like a champ until is died.
B. Sell the tires/wheels off the unit as they are still good and eBay the rest as a parts unit.
C. Part out the entire thing and sell the worthwhile parts separately.
Or, does anyone have other suggestions?