oil mix explained?

[wiggy6485]

HI, me and my brother have just started out in motocross, both just bought CR85r's and i know this will sound really stupid to people who have been riding along time but are we right to run the bikes with a ratio of 32:1? and if so how much oil in ML would that be in 5L of petrol? does it mean 32ml to every litre or 32ml in every gallon/5L's?. thanks, steve.

[crider400]

32:1 is a good ratio to start for jetting wise. All depends on you, how hard you ride etc.

http://www.at-speed.com/air/oil_gas_calc.html#top

[red2003]

To answer your question, no you are not calculating it the right way and if you mess it up, there is a good likelyhood you will seize the engine. 32:1 is fine for your 85's. 32 to 1 means for every 32 parts of gasoline you need one part of oil. So for every 32 mL of gas add 1 mL of oil. If you mixed 32 gallons of gas, you would add 1 gallon of oil. If you mixed 32 liters of gas, you would add 1 liter of oil.

5 liters of petrol = 5000 mL of petrol. Each 32 mL of petrol needs 1 mL of oil, so 5000 divided by 32 = 156.25. So add 156 mL of oil to the 5 liters of petrol to get a 32:1 ratio.

[wiggy6485]

ok thanks for replies, ive just done a mix but with less than what you've just said, glad i haven't run it up yet!

[Into the sunset]

Provided the bikes are jetted properly you can run anywhere between 32-50:1 ratios provided you are using synthetic oil. Some people run more gas but I wouldn't. We race a 2007 and it runs well at 40:1. We just tore down the top end and the cylinder was in great shape and the ring wear was minimal. The key is proper jetting and the service manual will provide the info you require. There is great info on this site too.

Don't neglect the air filter either as that can mess your jetting up as well.

[BluePills]

I find the american way of calculating your mixing ratio rather confusing, since I'm norwegian I use the metric system, liters instead of gallons and such...

The way we mix gas over here is by using percentages.

I mix my gas at either 2% or 3% depending on the conditions I'll be riding, I mix 2% if I'm going in the woods and I mix 3% if I'm riding on ice or fields (more RPM, More oil).

2% oil equals 200ml on 10 liters of fuel and 100ml on 5 liters.

3% oil equals 300ml on 10 liters and 150ml on 5 liters.

[SubTexel]

I find the american way of calculating your mixing ratio rather confusing, since I'm norwegian I use the metric system, liters instead of gallons and such...

The way we mix gas over here is by using percentages.

I mix my gas at either 2% or 3% depending on the conditions I'll be riding, I mix 2% if I'm going in the woods and I mix 3% if I'm riding on ice or fields (more RPM, More oil).

2% oil equals 200ml on 10 liters of fuel and 100ml on 5 liters.

3% oil equals 300ml on 10 liters and 150ml on 5 liters.

I mix 500ml to 5 gallons (~19L), for a 38:1 final mix ratio. Close enough to 40:1 for me, don't want to run any leaner since I run mine pretty hard all the time.

[BluePills]

I mix 500ml to 5 gallons (~19L), for a 38:1 final mix ratio. Close enough to 40:1 for me, don't want to run any leaner since I run mine pretty hard all the time.

It's always better to mix a little on the rich side rather than mixing a little on the lean side.

[scotty2fast]

There's a much easier way Guy's , buy a ratio rite cup and you will never have any mistakes. you can buy them at your local dealer for about 8 bucks.