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@declan Please follow the Manufacturer recommendations first before asking any of us.
It's best to 'guestimate' a healthy oil supply from that. But, from experience, as less oil you can work with the better!
I run my DT on a 42:1 mixture still. These road going 2strokes just don't require heavy lubrication.
@Darty true! And tbh even today's Mx bikes don't need a ridiculous amount of oil. KTM recommends 50:1 with most of their line up.
I think the freeride series are even less like 80:1???
Just read their newer bikes are on 80:1 with some people even going as low as 100:1 ! -
@declan Please follow the Manufacturer recommendations first before asking any of us.
It's best to 'guestimate' a healthy oil supply from that. But, from experience, as less oil you can work with the better!
I run my DT on a 42:1 mixture still. These road going 2strokes just don't require heavy lubrication.
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@Darty true! And tbh even today's Mx bikes don't need a ridiculous amount of oil. KTM recommends 50:1 with most of their line up.
I think the freeride series are even less like 80:1???
Just read their newer bikes are on 80:1 with some people even going as low as 100:1 !@Mightyman I was reading in Motocross Action Magazine that Husqvarna were recommending going from 40:1 to 60:1 to fix the jetting issues the MXA test team were having when running the 2017' TC250.
And it it worked! Incredible for a complete MX race engine.
Keep it real
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@Mightyman I was reading in Motocross Action Magazine that Husqvarna were recommending going from 40:1 to 60:1 to fix the jetting issues the MXA test team were having when running the 2017' TC250.
And it it worked! Incredible for a complete MX race engine.
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@Darty I wonder if that's because competition 2 strokes have a shitty service life so they only need to last a race before rebuild since leaner is faster in most cases
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@Darty I wonder if that's because competition 2 strokes have a shitty service life so they only need to last a race before rebuild since leaner is faster in most cases
@declan Not quite,
A leaner burn can still give the right operating temperature as the fuel is taking slightly more heat away from the cylinder walls.
But yes, as more friction occurs, more heat is generated and thermal expansion will eat into your cylinder tolerances quicker than a richer mixture.
It's hard to say, cylinder fill being very efficient nowadays!
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I've seen people run 2% premix together with the oilpump for breaking in a piston.
People did that back in our moped days aswell.
But for everyday use, no point. If you dont trust your oilpump, take it off.....Youre adding oil anyway, so why dont you?People seem so over-cautios about too much oil, i think theres a lot of information, floating around from back in the days with gummy been oil, that broke down and seperated from the gas if it was let to sit for a long period. This isn't racebikes, its everyday-bikes, they will run on a 5% premix, with a quarter of the gas beeing diesel. Tough reliable bikes.
Anyways, my guess is, at idle, the pump is flowing 1% or less.
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When I bought my bike, earlier owner says he have always put about 1% 2t oil into gas tank just to prevent engine hang (or ho do you say it in english?) and rest will be feeded by autolube. I did't put annything in gas, cause I trusted autolube. But what makes me think is the carb change...
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When I bought my bike, earlier owner says he have always put about 1% 2t oil into gas tank just to prevent engine hang (or ho do you say it in english?) and rest will be feeded by autolube. I did't put annything in gas, cause I trusted autolube. But what makes me think is the carb change...
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my rs use to eat plugs at first like that bad I carried a few and the tools every where I went I mean I would still carry plugs anyway with a 2 stroke but the point is it was because of too much oil and it would be a pain every time you was in a hurry and ran like shit after a few rides if I was you I would pick one or the other you're gonna have a bad time in the rain at the side of the road a few times if not
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Lending the thread a bit. Since I will be running the 170 kit, which Athena recommends 3% oil to, I'm not sure what to do. I know the majority just relies on the autolube and so do I want. From my understanding theses engines don't require massive amounts of lubrication. I won't use the bike for racing all the time. Mostly getting from A to B on a nice reliable Dt. That being said, I want to be able to twist the throttle without being scared of it seizing. During the run in, my idea is to mix 1% oil in the tank and also go with the oil pump. Then later go down to just the pump. What do you think?
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The rebuilt 89 Is running on the oil pump with a small amount of oil mixed in the petrol, only 5l of fuel, once that's gone oil pump only, a bit of insurance while everything beds in .
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@oldman but you are running the stock cylinder?
@irongamer727 I’m pretty sure he is yes
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I'd run 1% extra for the first tank, then forget about it.
The stock pump supplies plenty, a bigger piston wont require more oil from the pump. The pump keeps the ratio up, so more gas = more oil.
The higher compression 170 piston should also "suck" more fuel, thus oil.I dont know when the athena kits camo out, but just about no one runs 3% theese days, with modern oil.
If youre really concerned, fill up the oil tank,and the fueltank. Note how much fuel you fill up with, on the next handfull of tanks. Then note how much oil is needed to top of the oil reservoir, and do the math and see how many % the oilpump has supplied.
When putting around, or riding at moderate speed, the pump fill supply under 2%, which is fine for that use.
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I'd run 1% extra for the first tank, then forget about it.
The stock pump supplies plenty, a bigger piston wont require more oil from the pump. The pump keeps the ratio up, so more gas = more oil.
The higher compression 170 piston should also "suck" more fuel, thus oil.I dont know when the athena kits camo out, but just about no one runs 3% theese days, with modern oil.
If youre really concerned, fill up the oil tank,and the fueltank. Note how much fuel you fill up with, on the next handfull of tanks. Then note how much oil is needed to top of the oil reservoir, and do the math and see how many % the oilpump has supplied.
When putting around, or riding at moderate speed, the pump fill supply under 2%, which is fine for that use.
@jens-eskildsen The pump is driven from the crank, I wouldn't have thought the vaccum generated from the engine would be sufficient to overcome the tight oil lines. I really don't know, but happy to be proven wrong.
For me, well, the later pumps are adjustable, so just knock the value up to increase the oil on idle, and everywhere else.
I would have thought the 170 would need more oil, since it's a greater surface area that you're trying to protect. So it makes sense that the bike would need a little more. But I know people who ran them and never had a problem. Ultimately, use good high quality oils and you should be fine.
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Oilpump is driven from both vakuum and the cables, So it will still supply oil at high revs, with throttle closed, like when the revs are dropping, and engine braking. Just about any 2-stroke oilpump will do this.
Yes, you have a larger surface area, but you still have the same ratio between oil and fuel, and the 170 kit needs more fuel, so it also gets more oil.
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Oilpump is driven from both vakuum and the cables, So it will still supply oil at high revs, with throttle closed, like when the revs are dropping, and engine braking. Just about any 2-stroke oilpump will do this.
Yes, you have a larger surface area, but you still have the same ratio between oil and fuel, and the 170 kit needs more fuel, so it also gets more oil.
@jens-eskildsen The pump is driven directly from the crankshaft?
The pump is affected via two means, throttle and the crankshaft.
So shutting the throttle off at high engine speeds, would result in the pump being driven purely by the crankshaft. But there will not be any load on the engine. Which is not the same as a vacuum.
I'm not saying you're wrong. I think there will be a vacuum draw, I just think it'll be really small. Hence why when the pump fails, the engine fails. The vacuum simply is not enough to go by.
I just don't want people to get the wrong idea. And maybe I am wrong, but I believe I'm err'ing on the side of caution here.
It's another reason why you should always blip the throttle when going down hill on two strokes.
Furthermore, the vacuum will be in part created by the mixture of explosive gases, when the throttle is shut off, you're reducing those gases. Ergo, the vacuum created will be much less. That's why turbo cars have negative air pressure on the gauges.
Note the gif starts from negative 30. So when the throttle is shut off, the gauge exhibits negative air pressure. I don't know what direction that'll be. Presumably sucking air? So maybe the vacuum is enough.
Again, definitely a discussion topic as I simply don't know to be honest. But just want to lay out potential scenarios.
