Fuel type and mixture noob question

[ejtv]

So Santa delivered a Beta Evo 250 this am. I am new to this.

1) I heard from folks who introduced me to trials last month that they use high octane gas, like aviation fuel. I don't have easy access to aviation fuel. a- Will super unleaded no ethanol be OK? b- What if it has ethanol?

2) Manual calls for 4% mineral, 1.5% synthetic for the fuel mix. a- I assume this is "either or" rather than "both and." b- which of the two is better?

Thank you for the advice.

[DerViking]

I run something like 80:1 fuel to oil. What I actually run is 2 oz per gallon, this is handy as I use a 2 gallon can, and a 4 oz nalgene bottle to measure. I run yamalube 2-s by choice, but any of the 2 stroke oils will work.

Some run race gas, some don't. I have run 91 octane through mine for 5 years, with no issues. Ours does have Ethanol, doesn't seem to make much difference.

Welcome to Trials!

[jakbrand]

Did you have someone play a drum roll (see photo background) when you opened the box?

Beta trials bike...very cool

[nwcycle]

2 Ounces per gallon nets you a 64:1 Ratio,
Use Only Full synthetic mix, as you will clog up the exhaust with any blended premix.
You will get all sorts of who does what, so make your best decision with all the info.
We have been running Shercos at 80:1 with Amsoil Saber, It goes a long long way ,
Since you will be plunking around at low speed, the higher oil ratio is not needed,
We use usually a shell or top name brand gas 91octane plus, and I also add Octane booster just for kicks, only 1 Ounce per gallon, Not sure if its any benefit, but the crap we are buying top dollar at the pump, could all still be junk
BTW, Looks like your shelf needs a bit of bracing, hate to see that nice car dented :)

[neilking]

Great Bike!! I'm a +1 on the amsoil saber at 80:1. I run VP109 because I like consistency and no alcohol. That being said, the 250 does not have high compression and should run on premium pump gas. I loved my '11 250, it was very smooth and had extremely predictable power. My '12 was a great bike (still is with a new rider)also.

[lineaway]

Niels got the best answer. In modern oils I started with yamalube, then to Bel- Ray, and have stayed with maxima the last ten years. Maxima K2 at 80:1 (1.5 oz per gal) Maxima super m second choice.

[laser17]

We not only cant agree on oil, (because it probably doesn't matter much with todays synthetic oils) but it seems we almost get as many different opinions on what 80:1 gas to oil ratio means in terms of how much oil to add to 1 gallon of gas.

I guess thats why I use 100:1 in my GG - keeps it simple! If a US gallon is 128 oz then: for 80:1: =128/80 = 1.6 ounces of oil in 128 ounces (1 gallon) of gas. said another way, 1.6oz is 1/80th of a gallon.

likewise 100:1 = 128/100 = 1.28 ounces of oil per 1 gallon of gas.
75:1 = 128/75 = 1.7
50:1 = 128/50 = 2.56

[lineaway]

That`s funny lazer! Back when I ran 50:1 (in my measuring cup) I used 2.5 per gallon. So yes we all cheat and use the easy to remember system!

[10K]

Remember to rebuild it in 6 months!!

[laser17]

Originally Posted by lineaway

That`s funny lazer! Back when I ran 50:1 (in my measuring cup) I used 2.5 per gallon. So yes we all cheat and use the easy to remember system!

Sorry - must be the engineer in me. I'd go 2.5 and a smudge

[lineaway]

Originally Posted by 10K

Remember to rebuild it in 6 months!!

Just asked my son if we should rebuild his gasser today, he said no go ahead and ride it tommorrow dad,
So monday we`ll rebuild it! (Fork oil, linkage, tires, brakes and grips)

[nwcycle]

If anyone is looking to do a new top end ( Piston ) Etc, As long as its not cracked, you will need new rings and gaskets, and save yourself a few hundred $$ and send it out for piston coating, , This is the first thing we do in our bikes now, even new, it cost about $40.00 for 2 strokers, and a little more for the 4 strokers as they coat the top with ceramic,
Do some research at this site, I dont get a commission, just a guy who has an awesome product and last forever, if you have an excessive clearance issue, this is your fix, I have had 6 Trials bikes done, And about 25-30 racebikes done, both Motocross and Enduro 2 and 4 stroke.
This is a proven product and saves you a ton of cash......
Here is the link http://line2linecoatings.com/products.html
Once again, I have no affiliation to them, but you could say that you heard it from Ron in Illinois he will know

[broncobowsher]

80:1 with synthetic oil is just fine in a trials bike. May not be great for motorcross, but this is trials and not motorcross. If you ride a trials bike like a motorcross bike, well you got the wrong bike but that should run a motorcross type oil mix. My old '96 Fantic was running 80~90:1 mix and it still has a tight top end with tons of compression. 15 year old bike never had a top end done, EVER. Anyone saying you will need a top end in a trials bike in 6-months at 80:1 does not know trials.

As for oil, any quality synthetic. You just spent how much on the bike? A quart/litre of good synthetic is $10 and will last a long time. So long I forget the last time I bought it.

As for fuel, these are performance engines. They run a good deal of compression for that strong torque. The port timing will keep the cylinder pressures up. They need octane. Premium pump gas could work, I have never used it. Ethanol, it slightly leans out the fuel mix. The basic 10% should not really be a problem. Unless you are a pro you will never notice that it is slightly off. The problem is material compatibility. The materials in the fuel system are not intended for Ethanol blends. Short term it will all appear fine, long term it is more likely you will have wierd fuel system issues. For as little gas as these machines use I find sources of good gas. Also helps in fuel storage, non-ethonal fuels tend to be more stable when stored. I have used 2-year old AV gas that was stored outdoors (not in the bike) and it was still good, not varnished, bad smelling, etc. Half of the fuel had evaporated in that time, but what was still left burned fine. Personally I have access to 3 easy sources of race gas and at least one easy airport to get gas from. The Phoenix area pump gas goes bad so quick I can't store it for more then about a month before it starts turning into wierd jelly.

[Twin-shocker]

1) Avoid using fuels containing ethanol as the alcohol content can and does cause internal corrosion, particularly in relation to bikes which are used infrequently.

2) Trials bikes should be run on 100:1 mix for watercooled, and 80:1 air cooled. Oil used should be fully synthetic PREMIX ONLY, and mixing should be carried out using a syringe and measuring jug to be certain the ratios are correct.

3) On bikes which have been run using excessive amounts of oil (50:1 or more), the exhaust system will be completely clogged, and in most cases the rings will be gummed up. These bikes will run far better after exhausts have been properly serviced, and piston rings replaced.

4) High octane race fuels are not required for low revving low compression trials motors, and the slower burn of these fuels will often mean reduced throttle response, in comparison to a lower octane non ethanol fuel.

5) If E fuel is all that you can get, then expect to renew main bearings and con-rod bearings much more often, as internal corrosion caused by E fuel will greatly increase the chances of premature wear.