Jump to content
Sign in to follow this  

How old is TOO old for premixed gas?

Recommended Posts

I'm about to ride for the first time in about 2 months tomorrow, and I have almost a full tank, and about half a can of gas for my yz250. I've always wondered, what's the longest amount of time you can go before your gas goes "bad". Or does it even go "bad"? I believe when I got the gas I currently have, it was around the end of May. And just recently, I had my suspension rebuilt, and I started up my bike and took it for a spin in the backyard to test it out, and I didn't notice anything to weird going on with the gas I'm running right now. No weird smells, I don't think there was any bad pinging or anything.. But keep in mind, I just cruised around at about a quarter throttle. I'm afraid that if I really open up the throttle with old gas that it wouldn't lube the cylinder walls enough or something, and I would screw up my bike.

Can you guys let me know if I'm being paranoid or is there some merit to being worried about this? Because, I could just dump the old gas tomorrow and buy some new premix and all of that.. It would be a pain in the ass, because I'd have to rush to get everything ready in time, but it's still possible haha.

Share this post


Link to post
Share on other sites

Play it safe and throw in fresh gas & mix. It's hard to say what the shelf life of premixed fuel is but the problem is the oil will separate in the fuel which can do major danger if its not lubricating the crank and piston.

Share this post


Link to post
Share on other sites

If you use quality fuel and oil, it should be OK. I've run some that sat for five months.

If you are worried about this happening again use fuel stabilizer. What usually will happen is carb gunks up. You can always run the gas through your car and refill bike with new.

Share this post


Link to post
Share on other sites

Y risk it all I gotta say. Would you rather spend $20 for fuel and oil or $600 for crank, piston and cylinder...

Share this post


Link to post
Share on other sites

Play it safe and throw in fresh gas & mix. It's hard to say what the shelf life of premixed fuel is but the problem is the oil will separate in the fuel which can do major danger if its not lubricating the crank and piston.

You could always shake it up and re mix the oil.

The main problem with today's gas is the ethanol. If you are questioning the freshness, just go ahead and use fresh gas. I have used gas that sat for about 2 months. Seemed to run fine.

Share this post


Link to post
Share on other sites

I have a old Honda two stroke " Garage Queen" that gets started and run around the field a couple times a year. I rode it for a couple of hours straight 2 years ago and filled the tank then. Used fuel stabilizer and it still runs fine, starts first or second kick. In my regular week end bike I don't take the chance. I dump it in the old truck or use it in the weed whacker.

Share this post


Link to post
Share on other sites

If you used a stabilizer, no problem. If you are certain the gas is from the end of May, it will likely be fine. If not, I would probably drain the gas and run it in the lawnmower. Your 4 stroke lawnmower will run fine on old premix. That's where all my old gas goes.

Old gas is more likely to cause pre-ignition (heard as pinging) under heavy loads, and you probably know what that can do.

Share this post


Link to post
Share on other sites

2 months isn't bad. shake the bike good to re-suspend the premix . If you're really worried, drain it and use in the lawnmore, quad, your car ... Pre-mix gas works fine in a 4T . Btw, if you ride periodically like this, get some Sta-Bil fuel stabilizer and throw some in your tank and can. Although it would probably be fine. 3 months is a safe maximum time to use pump gas. If you have a small airport nearby, consider getting AvGas, it's about $5/gal and easily lasts a year or more, is 100 octane and has no ethanol...and you don't need any additives

Edited by avocasingletrack
  • Like 1

Share this post


Link to post
Share on other sites

Put in gasRx on every refill at the gas station. The stuff actually works. GasRx removes the water and distributes the ethanol if it has already separated. If you put it in a refill, it prevents it all together.

Edited by Yz4481f

Share this post


Link to post
Share on other sites

i say run it, I ran gas that sat in my bike all winter, I didn't get optimal performance but I also didn't have pinging issues. But if you're that worried about it then run it in your car/ lawn mower/ weed whacker and put fresh gas in.

Share this post


Link to post
Share on other sites

6 weeks for a small displacement (125cc or less) is my rule of thumb.

Risks are:

- fouling a plug, so don't warm let it sit idle too long and just get on and ride it up to half throttle till its warm;

- pinging or detonation (same thing), which is common issue on the current generation of YZ250s.

If in doubt, dispose of it with your recycled oil or in an alternative vehicle with a large displacement engine.

Share this post


Link to post
Share on other sites

i once started a 1999 cr250 with 8 year old gas (and hadn't been started for 8 years) in about ten kicks.

maybe they all stabilizers to fuel where you are (Alaska) , fuel sitting that long would surely turn into dry shellac / varnish , blocking mainly small carb parts and also fuel lines. Then you gotta take the whole carb apart and ultrasonic clean it

Share this post


Link to post
Share on other sites

If you have a small airport nearby, consider getting AvGas, it's about $5/gal and easily lasts a year or more, is 100 octane and has no ethanol...and you don't need any additives

+1 on the AvGas. Used it for several years, as a side benefit it has lead which helps the valves last longer if you're running a 4T. $6.59/gal here in Tulsa for 100LL last week when I bought it.

Share this post


Link to post
Share on other sites

+1 on the AvGas. Used it for several years, as a side benefit it has lead which helps the valves last longer if you're running a 4T. $6.59/gal here in Tulsa for 100LL last week when I bought it.

William R. Pogue Municipal Airport in Sand Springs has 100LL for $4.80/gal.

Here is a good avgas price finder for all the US. http://www.airnav.com/fuel/local.html

Share this post


Link to post
Share on other sites

That gas (and oil) is Fossil Fuel! It is already millions of years old before you get it. Fill er up and ride!

Share this post


Link to post
Share on other sites

William R. Pogue Municipal Airport in Sand Springs has 100LL for $4.80/gal.

Here is a good avgas price finder for all the US. http://www.airnav.com/fuel/local.html

Thanks for the heads up CamP. I usually stop at Christainsen (RLJones) because its convenient, but for a $2.00 per gallon difference I might stop at Pogue on the way back from riding Stillwater, or heading back from Red Castle.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...