How much 2-stroke oil

**Tue Jun 15, 2004 3:15 pm » Post: #1 » Download Post**

How much 2-stroke oil should I use on my Honda NSR 250 SP Mc21? My oil pump is disconnected, so i have to mix in the gas tank. The bike is upgraded a bit with racing pipes an boyesen reed valves.

**Tue Jun 15, 2004 4:37 pm » Post: #2 » Download Post**

Even,

I run a 32:1 ratio on my pre-mix oil. Some people run more, some less. I haven't had an issue with the 32:1 ratio yet.

thanks,
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Charles Gallant

**Tue Jun 15, 2004 6:44 pm » Post: #3 » Download Post**

HRC recommends 30:1 as outlined on the Carb Tuning page in the 250 Tuning section.

This is by no means the definitive setting however, just HRC's recommended base setting. They also recommend certain oils that may not be suitable for the average road rider, but they are the recommended oils!!

Andy.
NSR-WORLD.COM

**Wed Aug 10, 2005 8:30 am » Post: #4 » Download Post**

Do you produce more HP with more oil? Or more HP with less oil?

**Wed Aug 10, 2005 8:35 am » Post: #5 » Download Post**

Less horsepower either way. The bike will run crap with too much oil, and go bang with too little!
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

**Wed Aug 10, 2005 9:11 am » Post: #6 » Download Post**

Thanks Dave, got it. Will try the mixing soon. Very Happy

**Thu Aug 11, 2005 2:01 pm » Post: #7 » Download Post**

Moons ago we tested 20:1, 25:1, 30:1 and 40:1 on the dyno and track with a TZR250SP. It was a test for Castrol, using A747.

20:1 gave bad throttle response and power, and oiled the plugs at low rpm.

25:1 & 30:1 gave the same power, but 30:1 was crisper on the gas.

40:1 was crisp on the throttle, but scortched the bore at high rpm.

Jetting for every test was optimized.

I use 30:1 on the NSR. I use 40:1 on the CR500 Super retard cos it's a relatively low revver.