when to think about changing the oil depends on if you have a two stroke (mainly older bikes) or a four stroke… the two stokes churn their oil more and need it replaced faster if you are keen about maintenance. OTOH, there is no point being too careful with an old two stroker scooter here, they’re all a chunk of crap anyway compared to a real bike, and if they blow up it’s cheaper to get another one…
if you have a nice new four stroker, like a majesty, changing the oil regularly will help lengthen the life of the engine a lot: especially since they are so underpowered and spend much of their life with the throttle wide open, especially if you ride in the mountains at all.
so about every two months is a good bet: once you start using it, the oil will continue to age because of the acid that appears in it… of course this gets worse with increased mileage too.
two strokes also need the oil tank topped up regularly because they mix oil in with the fuel and burn it up continually…hence the blue smoke, and that lovely smell…
[quote=“urodacus”]when to think about changing the oil depends on if you have a two stroke (mainly older bikes) or a four stroke… the two stokes churn their oil more and need it replaced faster if you are keen about maintenance. OTOH, there is no point being too careful with an old two stroker scooter here, they’re all a chunk of crap anyway compared to a real bike, and if they blow up it’s cheaper to get another one…
if you have a nice new four stroker, like a majesty, changing the oil regularly will help lengthen the life of the engine a lot: especially since they are so underpowered and spend much of their life with the throttle wide open, especially if you ride in the mountains at all.
so about every two months is a good bet: once you start using it, the oil will continue to age because of the acid that appears in it… of course this gets worse with increased mileage too.
two strokes also need the oil tank topped up regularly because they mix oil in with the fuel and burn it up continually…hence the blue smoke, and that lovely smell…[/quote]
Uh…you don’t change the engine oil on a 2-stroke…you only “top it up”. And I’d guess for most two strokes they need topping up every 500 km or so…or else the engine will die.
I’m glad you mentioned two strokes burning oil in the fuel in your third paragraph because your first one really confused me.
[quote=“Mordeth”]Uh…you don’t change the oil on a 2-stroke…you only “top it up”. And I’d guess for most two strokes they need topping up every 500 km or so…or else the engine will die.[/quote]You need to change the gear oil on all scooters. About every 3000km.
not all two strokes take the oil that they spray into the cylinder with the fuel mix from the sump… many do, i am sure, but if you forget to check and yours doesn’t, then you’re cooking the oil for sure. some have a separate tank. the good old PGO 90 (actually an 82 but then who’s counting at that level anyway) has oil for both purposes in the tank accessed below the front of the seat, and a separate oil bath for the gears and transmission which can be accessed easily at the end of the swing arm/motor assembly (thats the big lumpy thing on the left side of the rear wheel).
BTW, the oil mixed into the petrol is there to cool and lubricate the piston(s) above the oil rings, and most of the piston cooling from below is done by oil splash from the sump oil… which is why strokers chew their oil quite quickly, as it gets splashed and churned up a lot, and there is a lot of engine breathing surge compared to fourstrokers. the oil in the mixture cools the top of the piston by reducing the temp of the burning mixture. DO NOT make your 2-stroke bike run leaner and thus hotter by taking off the air filter…unless you like stumping up for a new piston and barrel.
There are many differing designs of two stroke engines, some with wet sumps, some with dry, but I believe this: could be one of the more popular two stroke motor cycle engines out there. The petrol-oil-air mixture enters the crankcase by a valve and swirls around the bottom end, lubricating as it goes, then the downward pressure of the piston compresses the mixture and forces it to the top end through a bypass, the mixture is then compressed by the piston before finally being ignited. The rapid expansion of the gasses then force the piston downwards and keep expanding to force themselves out of the exhaust before the piston reaches bottom dead centre. The remnants of the burn are mostly forced out by the new fuel-oil-air mixture entering the cylinder…(briefly.)Edit, but the new mixture is controled and kept in place by the pressure developed in side the exhaust, which is why many two stroke motorcycles have a bulge in their exhausts.
The oil used in this type of engine is very important as the engine’s design only allows for uneaven lubrication. In a wet sump system however, as used by most 4 stroke cars and larger engined motorcycles, oil is constantly pumped to the places most in need of lubrication, offering extended engine life.
Two stroke oil must provide good lubrication as well as the cleanest burn possible, reducing both as much smoke and wear as possible.
Unfortunately I cannot offer much experience in the choice of two stroke oil, sorry.
[quote=“sulavaca”]There are many differing designs of two stroke engines, some with wet sumps, some with dry, but I believe this: could be one of the more popular two stroke motor cycle engines out there. The petrol-oil-air mixture enters the crankcase by a valve and swirls around the bottom end, lubricating as it goes, then the downward pressure of the piston compresses the mixture and forces it to the top end through a bypass, the mixture is then compressed by the piston before finally being ignited. The rapid expansion of the gasses then force the piston downwards and keep expanding to force themselves out of the exhaust before the piston reaches bottom dead centre. The remnants of the burn are mostly forced out by the new fuel-oil-air mixture entering the cylinder…(briefly.)
The oil used in this type of engine is very important as the engine’s design only allows for uneaven lubrication. In a wet sump system however, as used by most 4 stroke cars and larger engined motorcycles, oil is constantly pumped to the places most in need of lubrication, offering extended engine life.
Two stroke oil must provide good lubrication as well as the cleanest burn possible, reducing both as much smoke and wear as possible.
Unfortunately I cannot offer much experience in the choice of two stroke oil, sorry.[/quote]
:ohreally:
A really misleading post in my opinion.
Wet sump is when the crank case itself is the storage for oil.
Dry sump is when the a oilpump suck out all the oil and pump it trough exsternal filters or/and a external oil reservoar.
For 2 strokes there is wet sump, try sump where the cylinder lubrication oil is injekted trought holes in cylinderliners and the more used kind witch is not eather clasefyed as dry or wet, but has the oil mixed in the fuel and uses the crankase as savaging pump.
On the scooter, I change both the engine oil and gear oil (transmission) every 1000km. It costs me a few hundred and keeps the scooter feeling good. Some prefer to change the gear oil avery few thousand km, but I’ve always noticed that after 1500km or so, the gear and drive system really don’t run as smoothly as with fresh oil in it.\
A really misleading post in my opinion.
Wet sump is when the crank case itself is the storage for oil.
Dry sump is when the a oilpump suck out all the oil and pump it trough exsternal filters or/and a external oil reservoar.
For 2 strokes there is wet sump, try sump where the cylinder lubrication oil is injekted trought holes in cylinderliners and the more used kind witch is not eather clasefyed as dry or wet, but has the oil mixed in the fuel and uses the crankase as savaging pump.[/quote]
I’m sorry if it was all misleading. Of course for clarity, the type of engine depicted should be refered to as a dry sump, because the oil stored for lubrication is not within the crancase or sump, and is only injected temprarily until redirected to be burned. Wet sump two stroke designs may be rarer in terms of motorcycle usage, and may be found on larger vehicles, including trucks and locomotives (trains)
could be one of the more popular two stroke motor cycle engines out there. The petrol-oil-air mixture enters the crankcase by a valve and swirls around the bottom end, lubricating as it goes, then the downward pressure of the piston compresses the mixture and forces it to the top end through a bypass, the mixture is then compressed by the piston before finally being ignited. The rapid expansion of the gasses then force the piston downwards and keep expanding to force themselves out of the exhaust before the piston reaches bottom dead centre. The remnants of the burn are mostly forced out by the new fuel-oil-air mixture entering the cylinder…(briefly.)Edit, but the new mixture is controled and kept in place by the pressure developed in side the exhaust, which is why many two stroke motorcycles have a bulge in their exhausts.