Originally Posted by maniac57
Do you remember the beater Iron Horse 49cc bike I keep posting about? The owner runs used auto crankcase oil in that motor. It's been running four years now with god only knows how many miles and never had to pull the jug yet despite the abuse.
Original stock kit sparkplug never been touched
That should tell you something.
I'll post pics for sure if I ever have to tear it down....
Yep, I think many time we tend to over think these little work horses, it all about the crap shoot factor really.
Of course this is just my opinion but clearly the people in China that use them dont do loads of mods like many of us do, they dont have them set up for high rpms like myself and others here do and that also makes a difference, but if the engine is getting adi1uate lubrication on cylinder and bearings and the fuel air ratio is orrect or even a bit on the rich side these little engines should run for a very long time if kept below the hyper vibration point, if the engine is well balanced then that is even better, cleaned up ports, a good upper bearing, good gaskets on intake and exhaust, proper carb jetting and starting with a good engine on the positive side of the crap shoot factor and it probably gonna run great on most any decent automtive or 2 smoker oil.
High performance high rpm builds are an exception to some of this because the engine needs premium lubrication because of higher loads and higher heat on cylinder and bearings.
The engine Im usi g 25:1 of 40w non detergent in will top out at 39mph but actually runs best at 30mph or below since the vibes start kicking in fairly heavy at about 32mph, Im running a 30T on a 24" wheel and it just purrs at 28-30mph under no stress at all and has good power on hils.
Im gonna bet this engine will run for many years if I keep it and run it this way on the 40w oil @ 25:1
It has the same fwlt power and top speed as it did when it was on my favorite Opti2 @ 100:1 and just a small amount more smoke until its warmed up.