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new to trials, new to me beta, some questions

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I picked up a '01 beta rev3 270, no owners manual. I have some questions. What ratio should the premix be? I am using synthetic blend and 91 octane. What kind of oil in the gearcase? Can I use atf, thats what I run in my older ktm bikes. I am replacing the fork seals today. What weight fork oil? Can I use atf in the forks? How many cc? thanks

Isaac

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Don't know iwth the forks, but I run elf gear oil in the trans (what's recommended by the importer... so are the rest of thing things i'm gonna say) it's 500cc in there. As to gas, 91 isn't gonna cut it. it is gonna ping on it. As to ratio they recommend 70:1... i got mine and it was run on 80:1 and it looked fine and i run somewhere in the middle... closer to 70:1, but juts a tad leaner. Again, they reccomend elf oil in there. Works well for me so i'm sticking to it... plus i still have a bunch... though i do need some more gas, i'm starting to run low. In that regard i run 50% sunoco race fuel 50% whatever the highest the pump has. No diff from running 100% torco race fuel. idk if i'm forgetting anything. if i am ask.

A great place to find info is to email us beta. www.usbeta.com

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Rev-3 2001 (with some um....borrowing from the British importer site)

Engine Oil - 500cc (Light gear oil)

Fork Oil - LEFT Take out the spring. Fork fully compressed, 120mm air gap at top of fork 5 or 7.5 wt. (ATF can range from about 7.5 all the way to 15 and isn't really that consistant).

RIGHT Fork fully compressed, 60mm air gap at top of fork

Other - Petrol mix 70:1 Semi Synthetic Oil (70cc to 5 litres petrol)

Recommended Spark Plug NGK BP5ES

From my experiance these bikes like high quality oil in the gearbox or the clutch drags. You'll get a billion opinions on which one, I use Motul 2 cycle gearbox (10W-30) and it works fine. Red is right-on about the fuel, half-half race and good pump gas works fine, but keep it in a metal container or it gets really weird really quick.

congrats on the new bike!

Joe :)

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I really have to run race gas huh? That sucks, I called a motorcycle dealership and they want about $14 a gallon for 106 octane. Are there any cheaper places to buy or is that the price I should expect? thanks

Isaac

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You can find Cam2 for around 8 to 9 bucks a gallon at select Sunoco stations around Ma. . What town do u live in?

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Hey there IMC. welcome to the forum and to trials , youre going to have alot of fun , with both .. As far as race gas goes yes , BUT I buy pump race gas (106 @6.50/gal) and mix it 50/50 with 93 , to get 100oct. for about 4 bucks a gallon , which is a little easier to swallow than $14 a galllon !! Ask your local trials riders/club where they get gas ?? Someone will let in you in on their secret !! You can squeak by on 93pump but it will run sooo much better on the good stuff !! Good luck and just go ride !! :) Chad

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If i remember what the guy i got my bike from said corrently, he was able to get it to run on strait pump gas... however it required running so rich it was squirting oil out the muffler... i believe him based on what the packing looked like.

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I am in Ashfield, Ma. Does anyone know where I can get pump race gas around here? Also, how do I locate my local club?

Isaac

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I use Aviation Fuel (AV GAS 100-130) and mix it 3 gallons AV GAS to 2 Gallons Premium unleaded auto fuel..... until someone can tell me there is something wrong with that, I've been using it for over 15 years.

I don't believe in running it straight because AV GAS has properties meant for high altitude and cold temperatures and very low RPM engines, so blending it with auto fuel seems almost necessary.

The other thing I want to avoid is the alcohol blended fuels and AV GAS has none of that. Plus, I've heard that most unleaded premium auto fuel has no alcohol in it. If it does, they have to label it at the pump.

I buy the AV GAS from my local community airport, but you might want to clear it with the manager to verify it's going into an off-road vehicle as there is no road tax charged on it and the people selling the fuel could lose their license if caught selling it to road use vehicles, so they are sensitive to that. It helps tp show up with the bike in tow.

One last thing, there used to be a lower octane AV GAS available that was labelled 80-87 for octane rating. I have not seen that fuel at any airport for a long time, but just in case your airport sells it, DO NOT USE IT!!! It's lower octane than regular grade auto fuel.

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Hey Isaac,

There is a Sunoco pump is Westboro MA that sells CAM2 110 octane leaded gas for 8-10 bucks per gallon. I bought 5 gallons in the fall but couldn't bear the smell.

I'm sticking with 93 and my cylinder cap spacer that reduces the comp ratio to 9.5

If you're new to trials, make sure to check out an event this season. The New England Trials Assoc. is very active.

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, 91 isn't gonna cut it. it is gonna ping on it.

could somebody please elighten me on what, "ping on it"' means???

I've heard the term a few times and is lost on me. I run my sherco on std 91 octane and high performance synthetic oil, seems to run ok, but I wouldn't know any bettter, perhaps ours is a different blend of 91.

:)

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, 91 isn't gonna cut it. it is gonna ping on it.

could somebody please elighten me on what, "ping on it"' means???

I've heard the term a few times and is lost on me. I run my sherco on std 91 octane and high performance synthetic oil, seems to run ok, but I wouldn't know any bettter, perhaps ours is a different blend of 91.

:banghead:

"Ping" is the common term for detonation. Detonation in the dictionary is defined as: n. 1. The act of exploding. 2. An explosion.

That is when the air/fuel mixture explodes all at once even before the spark plug sparks. The mixture should hold off until the spark ignites it and then the fuel air mixture should "Burn" rapidly in a pre-determined pattern. The "Burn" gives a smoother "push" on the piston instead of the sudden BANG of detonation.

Detonation, Ping or Knock will sound like someone taking a small hammer to the cylinder and rapidly tap on it. It may sound like a rattle and will be more noticeable in a hot engine and is very destructive to your engine because it's hammering your piston and exploding even before the piston is ready for the down stroke, so it's almost trying to hammer the piston the wrong direction.

High Octane fuel has additives that make the fuel less explosive and supresses the fuel's tendency to "explode" while being compressed. The higher the octane rating, the more you can compress the fuel and air before it will explode by itself without the help of the spark plug.

You could go on to more detail and there is more to the story, but for now, that's probably more than you wanted to know. :)

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Just to sorta expand on what 2-ply said:

It can also be a flame prorogation starting someplace other then the spark plug, then having this flame front hit the one that was started by the spark plug. Basically pinging, knocking pre-detonation, detonation or whatever else u want to call it is bad. I've also heard it can sound like a bunch of little ball bearings in the engine.

As far as damage, it can burn a hole though the piston and i'm sure bend stuff in various places.

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Ahhh, pinging. It’s too bad you can’t get books like Gordon Jennings’, “The Two Stroke Tuner’s Handbook” in book stores and bike shops anymore. I guess the understanding of how an engine works is too much of a threat to the planet or national security.

“Pinging” refers to the sound an engine makes when the mixture doesn’t burn at the rate it was intended. Because the mixture burns quickly the sudden increase of pressure sounds like a marble being rattled in tin can. The effect was more pronounced on the old air cooled bikes with fins but it’s still audible on a watercooler.

Now there are two conditions that often get mixed. Pre-ignition and detonation. In normal combustion the fuel air mixture in the cylinder head burns in a controlled manner with a flame front traveling out from the spark. This propagates out to the outer reaches of the head. If you’ve ever wondered why the head is shaped with a squish band and not just a round chamber it is to control the speed of the flame front as the mixture temperature and pressure change during the burn with the goal to burn as much of the mixture as possible. The squish band cools the mixture further from the flame front slowing its burn time to optimize power and preventing it from spontaneously igniting before the flame front reaches it.

Pre-ignition is when the mixture ignites on its own without the spark. This can occur from a too hot spark plug or a fleck of carbon or even from a poorly designed cylinder head that traps hot mixture from a previous combustion cycle. Essentially you end up with several flame fronts burning all the mixture in the combustion chamber or one flame front starting at the wrong location. Needless to say (but I’ll say it anyway) this messes up the combustion pattern which should be controlled by the careful design of the cylinder head.

This causes the mixture to reach peak pressure at the wrong time, before the piston reaches top dead center. This means that it takes more of the stored energy in the engine flywheel has to push against the mixture in the cylinder to get the piston to top dead center where the mixture can release its energy back into the flywheel. Most of that energy is wasted, expended as heat rather than forward motion and a bike in pre-ignition will feel like it is losing power.

Now all that extra heat can push an engine into detonation. As the name sounds detonation is very bad. An air fuel mixture is intended to burn in a nice controlled manner in a certain amount of time. If the cylinder is too hot or the mixture pressure is too high or too lean the air fuel mixture can reach its flash point and spontaneously burn all at once. Bang! To give you an idea of what this looks like to an engine imagine you’re sitting there in the shop with your cylinder head off the engine and it is spinning happily away for some reason. Now every time the piston gets near the top of its stroke reach over and smack it with a hammer. Your engine will not thank you and at some point it will let you know it isn’t happy. Pre-ignition causes a loss of power and a progressive rise in engine temperature. Detonation causes a drastic loss of power, rapid rise in engine temperature and the characteristic engine knock that us old timers learned to dread. Mostly because swapping out a piston with the hole in it is a pain. Sure, you can get good at it but who wants to?

This is the reason I get antsy when I see someone say, “My plug looks too hot” and the suggested fix is use a colder plug. Best to find out why the combustion chamber is too hot. Use too hot a plug and the plug can become the source of pre-ignition. Use too cold a plug and you may be masking another problem.

OK so this brings us to another myth I often read on the web. The octane rating of fuel. “Will I get more power if I use racing gas?” Yes and no. No because the racing gas has roughly the same latent energy as regular old pump fuel. Yes because the octane rating is a measure of the fuels resistance to detonate so with a higher octane you can have a higher compression ratio and run it closer to the optimum mixture for maximum power since there is less need for evaporative cooling of the extra fuel.

I’m getting long winded. I need to go ride.

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Atleast u can go ride... i need a rebuild kit for my rear master cyclinder... found a gauge in the one o-ring... and a clog in a few other places (i might of caused the gauge... oh well... i need oil and some new rear pads anyway)

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Actually I can't. The little rubber mounts for the radiator sheared off and I'm waiting for new ones to arrive so I can reassemble the bike. The rear brake rebuild kit is no big deal. Just the piston/seal with a spring. I did one on my '05 and it took about 10 minutes. Course I didn't take it apart until I had the parts in hand so the system didn't need to be bled.

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