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Trike crazy
06-22-2016, 05:33 AM
Hello everyone, I have always mixed my gas in my toys at 32:1, I recently picked up 1986 ATC 250R and noticed it has a sticker on the neck that looks Factory saying 20:1 only, the guy I bought it from (who works at a Yamaha shop) said his boss told him 50:1 is all you need with the oils they have today, he also said he thinks it needs Rings because it is a little down on power. My guess is it's down on power because he's running no oil in the gas? I received the trike with a full tank of gas, my thoughts are dumping the gas or using it for my chainsaw. What mixture should I be running? Thank you.

yaegerb
06-22-2016, 08:43 AM
20:1 is on the neck for Honda legal purposes. Run 32:1 or 36:1 and you will be fine. And yes after 30 years it likely needs a ring job if its still factory fresh. Set of crank bearings probably wouldn't hurt either.

Dump the gas and run some fresh 91 mixed with klotz super techniplate

fieldy
06-22-2016, 09:31 AM
20:1 is on the neck for Honda legal purposes. Run 32:1 or 36:1 and you will be fine. And yes after 30 years it likely needs a ring job if its still factory fresh. Set of crank bearings probably wouldn't hurt either.

Dump the gas and run some fresh 91 mixed with klotz super techniplate

I was encouraged by my Kawasaki man to not run synthetic in my stock 86 2 strokes. I am confused on why and weather or not to use 91 or 93 with the valvoline non-synthetic.
On the other hand he has me run Belray synthetic with 93 octane in the 91 rm 250 he bored/built at 48:1 Leaves me kinda confused. I bought valvoline 2 stroke non synthetic and from things ive read here, i was planning to run it 32:1. Which octane would you use and why would synthetics not be suggested by him? (I will ask him next time i see him)
Detonation has something to do with it and the fact that gas is more crappy now, than in 86. I decided to run 93 octane till i saw this post.
This is in line with the topic so i suppose if someone could comment it should help others, thanks.

yaegerb
06-22-2016, 09:51 AM
I will keep this short and sweet. For a more detailed explanation there are many helpful documents out there that go into a huge amount of detail surrounding the topic of oil ratios, synthetics, etc. Klemm racing has a bunch of good technical documents on the subject.

Oil ratios are a function of RPM, period. A weekend woods warrior with rpm's varying from idle to 5k will do just fine with a mix of 40 or maybe even 50:1. A guy that earns a living in motocross, enduro, or road racing will take their motor to the RPM limits for sustained periods of time. Those motors therefore need more lubrication and require higher oil ratios per fixed volume of fuel/air...(e.g; 25, 20:1).

Octane need is a function of engine compression and head volume/squish. The lower the octane the easier it is to ignite. Therefore you wouldn't want to run 87 in a motor kicking 200lbs of compression with a squish of .030". For a stock 250r motor with factory squish 91 will be sufficient. Quite honestly with the quality of today's fuels, even with stock settings I run nothing less than 91 octane. I have found my banshee will detonate on 87. Today's fuels are shite, plain and simple. The only way for you to know exactly what octane to run is to perform an uncorrected compression ratio (UCCR) test. That test will give you definitive facts and numbers so you know exactly what octane your particular application needs.

Most quality two stroke oils today are synthetic. It is my opinion that they provide the necessary lubrication for our 30 year old crank trains. Now if we are talking 4 stroke, I still use only petroleum stock based oils in those. Two of my main oils for two stoke are klotz and maxima.

I like to run my bikes with a little less oil so it will provide increased cooling (richer fuel mixture) but not so oil-lean as to starve my crank train bearings for oil. Therefore I prefer to run 36:1 or 40:1 when tooling around in the woods and 32:1 or 28:1 in wide open or racing areas.

jb2wheels
06-22-2016, 02:18 PM
Don't overthink it.

Buy a quality, name brand synthetic or blend oil. Maxima, Klotz, Torco, anything from the Japanese OEMs,
Mix it 32:1 with premium pump gas. Ethanol free if you can get it of course.

Drain the carb after you ride if the trike will sit for more than a week.

Trike crazy
06-23-2016, 07:17 AM
Thanks for the input, the 86 is going to be my trail bike, however I have been told when I drive on the trails it looks like I think I'm in a motocross race. I always use klotz R50 and VP race gas whenever I can afford it, otherwise I run 93

The_Steve_Man
06-23-2016, 09:17 AM
Jerry Hall said that mx is very easy on motors because they are on and off the gas so much. I would say trail riding is the same. I ride hard in the trails, but I am always on and off the gas.

The best thing to do would be find an oil that you can get easy and run premium gas. Preferably nonethonal. If you stay with the same oil, mix, and gas, you shouldn't have any jetting problems. 32:1 is a safe commonly used ratio.

muthey
06-24-2016, 01:41 AM
I my self prefer yamalube 2r and run 32:1 ratio. I ran amsoil dominator for a short time in my tri-z and ended up smoking the crank, now I know it wasn't all the amsoil's fault but it just didn't seem to provide the same kind of lubrication that my yamalube 2r did as the crank when checked on removal for rebuild was a .001 too tight. My recommendation is either a non synthetic oil or klotz with castor bean oil if you can get it. the 20:1 ratio was for pre 2 strok oils, when you would use regular motor oil instead.