Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: Braap257 on August 05, 2010, 06:22:22 PM
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As I'm sure you guys know I recently picked up my 1st bike. A 2004 Yamaha YZ250. And the previous owner of the bike took very good care of it but he was running 40:1 And i think that seems kinda lean. I'm thinking about switching to 32:1 as most people I talk to agree 40:1 is not enough. But My question is can i switch over to 32:1? My bike seems to run rich "Alot of smoke and a little bit of spooge in the silencer" But I actually heard that running 32:1 may fix this??? ??? I live in Florida And its REALLY hot right now it averages about 92-94 degrees everyday and there is quite a bit of humidity. So would it be a good Idea??
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Doesn't matter the humidity, there's no oil in the air :) The air will affect how you need to jet the bike, not your mixture.
I run 32:1 and I've always run 32:1. If it was my bike, I would run 32:1.
However, here is an article that should clear things up for you.
http://jeep.off-road.com/dirtbike/tech/two-stroke-gasoil-ratios-20502.html (http://jeep.off-road.com/dirtbike/tech/two-stroke-gasoil-ratios-20502.html)
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In my opinion, 32:1 is a good ratio. I run it in all my bikes; Yamalube 2R (not the S) oil. Good stuff. If you are running rich (or lean), you want to re-jet, not just mess with your ratio. Find an oil and ratio you like, and then jet accordingly.
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32:1 For life.
Yamaha recomends 30:1 or 32:1, I don't remember, But if you don't know who to trust, I would fall back to the manufacturers recomendations.
I do re-jet for altitude and weather, Your probably never going to get away from that.
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Have you put fresh fuel in it and taken it for a run yet ?
You may not be running rich , just old fuel. Do that first and then go from there.
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Go full synthetic you can run 50:1. Maxima, amsoil.
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I run fuchs silkolene synthetic 50:1
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I run fuchs silkolene synthetic 50:1
Voila!!!!
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Have you put fresh fuel in it and taken it for a run yet ?
You may not be running rich , just old fuel. Do that first and then go from there.
Unfortunately no, I have just been so busy. But I managed to drain the old fuel and put a fresh plug in tonight. And I'm taking the bike to a buddies house on Wednesday. He's been racin motocross for 4 years now. We are gunna check over everything from the handlebars to the wheels ;D Amongst those we are gunna focus on seeing if the bike needs to be jetted or carb tuned. And seeing what needs done with suspension.
My new gear didn't come in today.... >:( I'm hoping i get a call tomorrow :)
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From what i've read, running a leaner ratio will get you an extra pony or two. But richer will help your bike last longer.
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I have run 40:1 with Yamalube 2R on the same top end in my '98 YZ250 for over 60 hours, no problems at all. Still has enough compression to bruise my foot when kickstarting!!
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In my opinion 40:1 with a high grade synthetic oil will work good.With todays pump fuels being as bad as they are i would try to mix some leaded race fuel or a good fuel additive with the pump fuel.I have been using pj1 anf there is a noticeable increase in throttle response and pull.
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i was running 32:1 or more back in the 70's. Oil lubrication technology has made huge strides since then. It's no longer the QUANTITY of oil, but the QUALITY of oil. That's why guys using full synthetic can feel confident at 50:1.
One thing is for sure though - if you change the ratio you should rejet, because each droplet of fuel no longer contains the same amount gas i.e 32:1 = 96.87% gas per droplet, and 50:1 = 98% gas per droplet