Gas ratio

[Lgwillie]

I recently picked up a 2001 yz 125 and the guy I bought it off of says he runs it 56:1 with gold spectra premix. Do you think I should run it richer or leaner. And is the gold spectra premix good?

 

[VMax]

This should start quite the debate. To save time id say stick with an oem spec. I won't get into what I do just yet.

 

[2strokesteve89]

This should start quite the debate. To save time id say stick with an oem spec. I won't get into what I do just yet.

Don't do it.......you'll get your ass handed to ya.

 

[VMax]

Don't do it.......you'll get your ass handed to ya.

Ya, long distant as whoopin ain't no fun! Can't get up close and personal here!

 

[Lgwillie]

Umm... So what should I do. I Don't know much about dirtbikes

 

[VMax]

Ya, long distant as whoopin ain't no fun! Can't get up close and personal here!

Hey 2stroke, u gonna help this gentleman plse cause I'm about too!

 

[PALMER84ONE]

Spectra premix is a wonderful oil to use. 56:1, not to sure, but.... If thats what he ran, I would run the same until new top end. Then I would settle into a 32:1 Yamalube as recommended by Yamaha manual. I run it on all my YZ's and they have zero problems. I prefer the Iridium plug but Jim (UK jim, jimcr250, jimzee, jim bob, UK, Jimmy, Jammin jim) likes the standard plug and 32:1. UK Fuel is a higher octane than ours in the US crap. So, I run a sunoco 112 super with the 91 pump 4:1, with the Yamalube. Now there are a bunch of guys out there that like other stuff and it is no problem to follow what they use. The problem only occurs when you change in the later part of an engines life.
Your turn @VMax @ossagp @2strokesteve89

Why it doubled?

 

[Lgwillie]

Im probably just going to run it 50:1, but I don't want to cause engine damage. It idles perfectly and doesnt bog out with whatever he has in it now. I drained all of the gas in case it was old

 

[2strokesteve89]

Marvel mystery oil at 100:1

 

[VMax]

I'd go with what Palmer said!

 

[PALMER84ONE]

I'd go with what Palmer said!

WHAT!!!! No debate? PUSSY!!!!

 

[2strokesteve89]

WHAT!!!! No debate? PUSSY!!!!

He'll leave that to you.......being the master debater an all.

 

[SRAD97750]

Im probably just going to run it 50:1 ...

That is a dangerous assumption.
Making the Oil/Fuel Mixture "Richer," inversely brings the Air/Fuel Mixture "Leaner."
Lean Air/Fuel mixture is the dangerous one.

I would run 56:1 if that's what the previous owner has been running. Take a look at the next top end to see how it looks.

You need to adjust jetting to change Oil/Fuel mixture.
This will require tuning, multiple plug chops, and being certain you have maintained a stoichometric Air/Fuel mixture after changing the oil/fuel mixture. -BIG DAN

 

[Lgwillie]

So when I put in a new top end it
Will run ok with 32:1. I have another question. It seems to not have a lot of compression, but it starts up first kick

 

[VMax]

I just finished a 242 mile drive at 80mph after a long days work so that's the reason I quoted myself, this time! However there are many ways a guy can go to mix your gas. I can say that after 40 plus yrs experience I have found the perfect mixture and I'm not telling anybody!