I still can't believe some moto-mag would deliberately try to frag a motorcycle engine to no purpose... I mean, if they had decided to do the entire debacle in the article on the dyno, for instance, just to see some data on what kind of effects on performance this kind of abuse had I could sort of see it, but...
Well, anyway - the article did remind of a series of tests Husqvarna did back in the early 1970's (back when they were Swedish...
). They wanted to see what effects leaner and leaner fuel-to-oil mix ratios had on their two-stroke MX'ers. They started out with their normally recommended 20:1, ran the bike on the dyno for a while, then leaned the ratio to 32:1 and repeated, etc. Allof this was done with Castrol R "bean oil", as I recall, which was then their recommended pre-mix oil of choice. They continued to lean the ratio down to 40:1, 50:1, and so on... They did have to re-jet a couple of times to make the bike run clean, but the test went on... Right down to where they were running *NO* oil in the damn thing - just *STRAIGHT GASOLINE*!
One thing to point out - after each of these runs they disassembled the engine and check wear, clearances, etc. - and all through the test the engine was not really wearing all that much, so they kept continuing with the same parts.
Well, as I said, they finally got to where they were running the poor beast on straight gasoline, with no pre-mixed oil, and the engine kept running fine except for some slightly elevated head temps. So they finally just decided to keep running it until it failed... Only it never did. Never seized. Never cooked off the lower end bearing. Never blew up. They ran the thing on the dyno for like 48 hours like this, and finally gave up. They disassembled the engine, and though they found excessive ring, piston, and bore wear, along with a badly discolored rod and lower-end bearings (along with some crankpin galling), the engine didn't appear it was going to give up the ghost any time soon.
This was the test that changed Husky's recommended fuel/oil ratio from the previous 20:1 to 32:1, as they found the engine produced the most power at 32:1. It lost power at any other ratio, but it kept on running.
The test was all documented and very scientific, etc., and it made for fascinating reading. I had a copy of it somewhere, and I imagine if I dug around long enough in all my accumulated junk I could find it. If I ever do I will post it here.
Still pretty wild that a Brit moto-rag would try and blow up a poor, unsuspecting Kwacker!
Wonder who the bike belonged to, and whatever happened to the thing?
Cheers!
Dallara
