2 stroke premix amount

[cdeez]

What is the ratio of oil for a 2 stroke minarwlli engine for premix ?

[TheAmishSasquatch]

Thats sort of an open ended question. Id suggest reading up on pre mixing. Thetes really too many variables, opinions and preferences to answer this. If you really just dont give a shit and just want someone else to put the effort in for you, you could always look at the bottle and it will tell you how much to add per gallon for a particular ratio.

[cdeez]

I'm asking what ratio 50:1 25:1 37:1

[eclark5483]

Try 32:1 that's a good starting point, but you really should research this a bit more, like TheAmishSasquatch said, there are too many variables here.

I guess questions I have, are what kind of bike is it? Did it have an oil pump originally? Did you check to make sure it no longer has one? Just asking what ratio you should mix an engine at, is just asking for problems.

[tsimi]

That would depend on your setup. Carb, cylinder, stock oil pump still running? and so on...
Some say 50:1, 40:1, 32:1....
I personally run 32:1 on my MHR Replica, 21mm PHBG, City 16 pipe setup and I think it is slightly oily but that is good for my aluminum cylinder.
Maybe a sport grade, iron cast could run with 40:1 or even 50:1?

Same like the carb jetting, start rich and work your way down.

[ThomasTPFL]

The bikes I manually mix I do 3 oz to a gallon, that like 40:1 I think? Ain't froze one yet but I have trashed three cranks.

[niz76]

Another variable is the quality of the oil. A lot of the high quality stuff recommends a mix of 50:1, but that mix with a low grade 2t oil might not cut the mustard....

[gsx600racer]

Feb 24, 2017 22:15:02 GMT -5 tsimi said:

That would depend on your setup. Carb, cylinder, stock oil pump still running? and so on...
Some say 50:1, 40:1, 32:1....
I personally run 32:1 on my MHR Replica, 21mm PHBG, City 16 pipe setup and I think it is slightly oily but that is good for my aluminum cylinder.
Maybe a sport grade, iron cast could run with 40:1 or even 50:1?

Same like the carb jetting, start rich and work your way down.

+1 ^^^^ what he said

[cdeez]

Ok great info , I have a vento r4 and yes it has a oil pump that is still on the bike but is not pumping to anything and is not connected to my throttle cable. I've changed out to a 24mm oko carb , new 70cc bb kit and new exhaust. I just wanted a starting point so I don't run it too lean

I would love to remove my oil pump but I need to get my hands on a flywheel puller first , but reality does it really make a difference if it stays or its removEd?

[eclark5483]

Yes it makes a difference.

Like lets say you have a pump and it is in fact working correctly, and you decide to upgrade to a BBK.

Now obviously, you are gonna need extra lubrication for the bigger piston, so you need to figure out exactly how much more you will need.

Lets say a stock pump puts out 50:1 for a stock piston and you want to lubricate more for a bigger piston.

You then need to do some math to figure out what your EFFECTIVE rate is if you add oil to the gas tank.

So as an example... the pump does 50:1 and you add 96:1 to the gas. How you calculate this is add the 50+96, which equals 146. You then divide by 2 twice.. Or 146/2=73, then 73/2= 36.5:1

So your EFFECTIVE lubrication ratio ends up being 36.5:1

See how that works?

The variable here, is how much the pump puts out. But then another thing to consider is the linear plane.

An easy explanation for that, is say the engine is only spinning at low rpm, and the pump puts out, say only 70:1 at "X" rpm, but as RPM increases, so doesn't the volume of oil as the gear spins faster till it reaches it's peak of say 50:1.

So what you would need to calculate, is how much EXTRA oil to add to be stable between the pumps LOW 70:1 ratio, and it's HIGH ratio of 50:1. If you don't calculate this correctly, you could end up saturating yourself with oil, or even worse, you will run lean (and risk blowing the piston), at high rpm. In the scenario of using 96:1 in the tank with a pump that peaks at 50:1 but has a low of 70:1, you end up with 41.5:1 as a LOW, and 36.5:1 as a high. This, may, or may not, be acceptable lubrication!!

But then that is just one example.... again, this is why we say there are too many variables at play here when you just ask "OK, WHAT PREMIX SHOULD I USE".

[gsx600racer]

Feb 25, 2017 1:41:38 GMT -5 eclark5483 said:

Yes it makes a difference.

Like lets say you have a pump and it is in fact working correctly, and you decide to upgrade to a BBK.

Now obviously, you are gonna need extra lubrication for the bigger piston, so you need to figure out exactly how much more you will need.

Lets say a stock pump puts out 50:1 for a stock piston and you want to lubricate more for a bigger piston.

You then need to do some math to figure out what your EFFECTIVE rate is if you add oil to the gas tank.

So as an example... the pump does 50:1 and you add 96:1 to the gas. How you calculate this is add the 50+96, which equals 146. You then divide by 2 twice.. Or 146/2=73, then 73/2= 36.5:1

So your EFFECTIVE lubrication ratio ends up being 36.5:1

See how that works?

The variable here, is how much the pump puts out. But then another thing to consider is the linear plane.

An easy explanation for that, is say the engine is only spinning at low rpm, and the pump puts out, say only 70:1 at "X" rpm, but as RPM increases, so doesn't the volume of oil as the gear spins faster till it reaches it's peak of say 50:1.

So what you would need to calculate, is how much EXTRA oil to add to be stable between the pumps LOW 70:1 ratio, and it's HIGH ratio of 50:1. If you don't calculate this correctly, you could end up saturating yourself with oil, or even worse, you will run lean (and risk blowing the piston), at high rpm. In the scenario of using 96:1 in the tank with a pump that peaks at 50:1 but has a low of 70:1, you end up with 41.5:1 as a LOW, and 36.5:1 as a high. This, may, or may not, be acceptable lubrication!!

But then that is just one example.... again, this is why we say there are too many variables at play here when you just ask "OK, WHAT PREMIX SHOULD I USE".

Feb 25, 2017 1:41:38 GMT -5 eclark5483 said:

Yes it makes a difference.

Like lets say you have a pump and it is in fact working correctly, and you decide to upgrade to a BBK.

Now obviously, you are gonna need extra lubrication for the bigger piston, so you need to figure out exactly how much more you will need.

Lets say a stock pump puts out 50:1 for a stock piston and you want to lubricate more for a bigger piston.

You then need to do some math to figure out what your EFFECTIVE rate is if you add oil to the gas tank.

So as an example... the pump does 50:1 and you add 96:1 to the gas. How you calculate this is add the 50+96, which equals 146. You then divide by 2 twice.. Or 146/2=73, then 73/2= 36.5:1

So your EFFECTIVE lubrication ratio ends up being 36.5:1

See how that works?

The variable here, is how much the pump puts out. But then another thing to consider is the linear plane.

An easy explanation for that, is say the engine is only spinning at low rpm, and the pump puts out, say only 70:1 at "X" rpm, but as RPM increases, so doesn't the volume of oil as the gear spins faster till it reaches it's peak of say 50:1.

So what you would need to calculate, is how much EXTRA oil to add to be stable between the pumps LOW 70:1 ratio, and it's HIGH ratio of 50:1. If you don't calculate this correctly, you could end up saturating yourself with oil, or even worse, you will run lean (and risk blowing the piston), at high rpm. In the scenario of using 96:1 in the tank with a pump that peaks at 50:1 but has a low of 70:1, you end up with 41.5:1 as a LOW, and 36.5:1 as a high. This, may, or may not, be acceptable lubrication!!

But then that is just one example.... again, this is why we say there are too many variables at play here when you just ask "OK, WHAT PREMIX SHOULD I USE".

Great post...

[niz76]

You can leave the pump in place and just not use it. I usually like to remove it as there's a gear that runs off the crank in there, but you don't have to...

[benji]

I've heard before that the stock pump will work fine for mild bbk setups. I'm using the stock pump on my minarelli vert w a ruima cast "street race" kit. Still smokes.

[90GTVert]

The stock oil injection system does work alright on sport kits from what I've seen... till it doesn't. I swap mine to pre-mix so I know what I'm using and because I've seen pumps fail before. So far, I haven't forgotten to add oil so my record is a little better than the pumps. The convenience of pre-mix is very nice, but it's just one more thing to fail from my outlook.

[joshua864]

Ok so what oil do you guys preffer. I'm following this thread as I want to ditch the pump all together when I installmy kit