Premix

[go_hercules]

I have a Dirt Squirt that I let sit with premix in the tank and carb for about two years. I cleaned everything out no problem, but it was really gummed up and the brass float was somewhat corroded. I understand the gumming up but I am thinking the corrosion is maybe from the ethanol in the pump gas which attracts water maybe. I intend to run it a lot more frequently to keep it clean this time. But I was wondering what you guys do with bikes that sit mostly. Maybe avgas or race gas? Draining it is not an option, too much work for a fun pastime. I even thought of Sta-bil but have never used it and didn't know what it does with two stroke oil. Thanks.

[matt glascock]

go_hercules,

There are two recent discussions on the forum covering this topic. You might check out the threads titled 110ll avgas and life of premix for some helpful insight on this topic.

[thrownchain]

Use non ethanol gas if you have access to it, and for "long term" storage, stabil wouldn't hurt.

[relic]

I prep over 150 boats each fall for winter storage. About a third are still two strokes and some of those run premix. Every one gets run to temp with a storage/stabilizer product called "Startron" added to the gas. We've been using it for several years now with good results. Never have an issue in the spring. I use it in all my bikes as well.
I think any quality stabilizer will work well, I just mention this one as it's formulated for ethanol gas, (prevents phase separation) and has worked for us.
Ken

[go_hercules]

Thanks for all the replies. i will read up on Startron. I can get avgas locally so I might just keep some around just for this bike. I like the idea of avgas since there is no ethanol but I think the key is to remember to ride it around the neighborhood every few weeks. Thanks again everyone.

[ossa95d]

Hercules,
I tried avgas in my race bikes and found it to be a terrible choice. I think others have had the same experience here on the list.

[Bullfrog]

Yup, you will be better off finding a source of non-ethanol auto gasoline.
Ed
PS: Been there, done that on the aviation fuel thing.

[go_hercules]

I did a search for non ethanol gas and couldn't find any here in Ventura County (Southern California). I know a guy who runs avgas in about ten vintage bikes, two and four stroke street and dirt bikes, with no problems. What downside are you guys seeing with avgas?

[racerclam]

av ga s aint bad just not ultimate for the altitude on the ground its specific gravity is designed for High altitude and better performance can be had with race fuel. Av gas will ignite slower slower and engine response will be a bit slower . One good thing is it wont vapor lock down here but then again biles dont have that problem

Rich

[Hydraulic Jack]

Do a Google search on "avgas in motorcycles." You will find all the opinions you need, but also here and there a fact or two.

Avgas is formulated to work in civil aircraft using aircooled four stroke engines running at very modest rpm and a wide variety of density altitudes. If I remember correctly from my short flying career, most small planes run around 2,200 to 2,400 rpm wide open and rarely see drastic or rapid throttle changes. Avgas even at 100LL is about four time the lead content of motor fuel back when motor fuel had lead in it. That would be a very high lead content.

Used primarily as an octane device, lead slows burn rate effectively screwing with your ignition timing and causing the cylinder wall to see longer exposure to flame. Cooking off the oil film in a two stroke isn't a good way to go. I see no upside to using avgas in a motor bike two or four stroke. I would think the presence of significant lead would be more harmful than the ethanol content in pump gas.

[go_hercules]

Thanks for the info. My friend I mentioned runs avgas in a Bultaco Pursang I sold him here at sea level and it runs great. He also runs it in several Honda CB750's on the freeway and they all run great. I'm sure it's possible that some bikes just don't like it but I think a lot of it might just be speculation or some other issue. Now my friend also has no issues because he runs the bikes a lot so they never sit long periods like mine. Maybe that's the problem for a lot of people too.

[go_hercules]

I just saw this stuff on the Home Depot site. Comes out to about $23.50 a gallon so you wouldn't want to run the Baja 500 with it. Says it's ethanol free - ever heard of such stuff?

http://www.homedepot.com/p/TruFuel-40-1 ... /203572105

[go_hercules]

I also saw this on the Tractor Supply site. It is made by VP.

https://www.tractorsupply.com/tsc/produ ... _vc=IOPDP1

[Bullfrog]

A bit of an apology is in order. I re-read this thread and (re)discovered you are asking about fuel for a Dirt Squirt . . . and it sounds like your riding will be general knocking about. No hint of competition/racing use. Sooooo . . . if that is correct, then I'd like to modify my advice to better match YOUR needs (as opposed to MY needs ). I still think it is best to not use ethanol blend gasoline, and since auto pump gas without ethanol isn't available anywhere near you - then AV gas will be fine. Nothing about AV gas will be risky for use in your Squirt engine, and there won't be any ethanol. My previous comments were shaded tooooo much toward a concern for less than optimal engine output (which you would only notice if you were out racing). The AV gas is stable, formulated to minimize detonation and it is AVAILABLE to you. So, go for it. It will be better than ethanol blends.
Ed

[Bill2001]

Good discussion. Gasoline has always been rather a "holy water" topic since the late '70's when lead levels were reduced and unleaded gas was mandated. In four-stroke engines there were problems with abnormal valve face wear-- lead lubricates valve seats-- until they straightened their metallurgy out. We'd spike the gas tank with leaded AVGAS every few tankfulls to keep lead levels up. Then came the PITA of ethanol, which we are dealing with now. By avoiding ethanol.

Ah, to be a bobblehead and drive a Prius...

[Hydraulic Jack]

Gasoline originally contained TEL (tetra-ethyl lead) as an anti-knock agent effectively raising octane rating by slowing flame spread rates. It was discovered somewhere in the history of the auto industry that the lead was also protecting valve cylinder head interface by creating a sacrificial deposit. The transition to unleaded fuel required an understanding of what lead had been doing for four stroke motors so that an alternative could be found. I think the answer was found in stellite valve seats, but I may remember the metallurgy incorrectly.

In two strokes during the days of leaded gas, lead fouling was a constant issue. As far as I know, lead played no part of two stroke motor function or longevity other than the tendency to suppress detonation. Pretty much, that's what ethanol is doing today, although ethanol also has lots of bad baggage in the function of anyone's engine. Not that the government cares about such things.

Without specific changes in ignition timing to accommodate high lead content, leaded fuel won't efficiently burn during the combustion cycle, and some part of the fuel charge will burn farther down the power stroke and some perhaps even after leaving the cylinder. This usually results in elevated running temperatures and decreased performance. Avgas has and has always had more lead in it than pump gas. Lots more. The government let it go mostly because there really aren't that many general aviation small planes out there, and they tend to deposit exhaust way up above us where we don't notice the pollutants.

The question here is whether the benefits of higher octane leaded but ethanol free fuel outweigh the downside of ethanol laced pump gas. It would be a fair topic for a technical debate. Almost everyone in the motorcycle world knows ethanol is not good for bikes, and most have forgotten that lead wasn't all that good for dirt bikes either. I wouldn't use the premixed race gas or chainsaw gas you may find at the hardware store or the bike dealer, mostly because of cost but also because you don't have control of the premix oil or ratio. Straight race gas is too expensive for daily use.

You can mitigate the ethanol issue with a proper additive, but it won't take the ethanol out of pump gas, it just holds it in suspension longer. Whether it does anything to protect rubber parts, I don't know. If you think 10% ethanol is a bummer, wait till the government mandates 15% minimum ethanol and outright bans alcohol free gasoline at the pump.

[michael_perrett]

I was told recently of a method to remove ethanol from gasoline. Did not try it since there is non ethanol available here. Add water (10% of a gallon) to a gallon of ethanol gasoline. The water is suppose to attract the ethanol and will settle to the bottom of the container. Drain off the bottom. Could try it in a glass jug and see how it goes.

Mike Perrett

[Hydraulic Jack]

Removing ethanol from gas would be a good thing, but if you take the ethanol out of 91 octane pump gas you are not left with 91 octane gas.