32:1 to 40:1

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crack rock

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Feb 28, 2006

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• Aug 28, 2006

• #1

thinking of switching from 32:1 to 40:1 on my rm 250. is there any performance gains with 40:1? will it cause the main bearings or top end to wear quicker? also how much leaner will i have to jet it?

 

Rich Rohrich

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Jul 27, 1999

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• Aug 28, 2006

• #2

crack rock said:

thinking of switching from 32:1 to 40:1 on my rm 250. is there any performance gains with 40:1?

Click to expand...

No

will it cause the main bearings or top end to wear quicker?

Click to expand...

Maybe

also how much leaner will i have to jet it?

Click to expand...

You are unlikely to notice any difference unless you are changing to a different type of oil at the same time. Even then it's highly unlikely that you would have to change jetting due to such a small volume change in oil.

 

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psustang89

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Jun 22, 2006

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• Aug 28, 2006

• #3

I know some guys who woods ride competitively and they run 50:1. I was told that 32:1 is more for MX, high stress riding. So according to them it depends on what kind of riding you do. It makes sense that you would need less oil if you're lugging around the woods than if you're wide open on a MX track. I'm running 40:1, but my jetting isn't perfect yet...

 

M

magneto

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Nov 14, 2001

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• Aug 28, 2006

• #4

I run 32:1 (Golden Sprectro) in my EG ported CR5 and it doesn't seem to be lacking power :laugh:

I always figured oil was cheaper than parts and more oil should equal less wear on all internal parts.

Seems like I read somewhere that with optimal jetting you could actually get more power with richer oil/gas ratios due to better ring/cylinder sealing... OK, I got my flame suit on fire away!

 

D

DLHamblin

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May 27, 2005

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• Aug 28, 2006

• #5

magneto said:

I run 32:1 (Golden Sprectro) in my EG ported CR5 and it doesn't seem to be lacking power :laugh:

I always figured oil was cheaper than parts and more oil should equal less wear on all internal parts.

Seems like I read somewhere that with optimal jetting you could actually get more power with richer oil/gas ratios due to better ring/cylinder sealing... OK, I got my flame suit on fire away!

Click to expand...

You are correct.

 

C

crack rock

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Feb 28, 2006

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• Aug 28, 2006

• Thread starter
• #6

looks like im stickin with 32:1

why do some people run a leaner mix if there is no performance gain and more wear on the engine?

 

Papakeith

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• Aug 28, 2006

• #7

because they can save .000000002 cents on oil costs. I used to run at 20:1 worked just fine for me.

 

sick 96 250

Damn Yankees

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Jul 16, 2004

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• Aug 28, 2006

• #8

i've ran 40:1 for the past 10yrs at least and never had any problems. 32:1 compared to 40:1 is not much, once you start getting up to 50:1 and more thats when I would worry