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Join Date: Jan 2011
Location: Smack in the middle of Illinois
Thanked 287 Times in 282 Posts
You can get gas without ethanol - you just have to shop around for it - I was buying VP Racing SEF 94 octane from NAPA, Big R Farm Store or directly from VP Racing. The killer was I had to pay a $50 hazardous shipping fee + UPS shipping charges to get it shipped from VP. Or I had to drive about 12 miles or more to get ethanol free 91 octane at Casey's General Store's in neighboring towns. Last year Casey's built a new store in our town, now I just drive across town and to get ethanol free fuel. Casey's realized how big the market was for recreational fuel and is capitalizing on it. All seasonal engines should be run on rec gas. Motorcycles, snowmobiles, lawn mowers, snow blowers, stand-by generators or any engine that may be unused for more than 15 days needs ethanol free fuel in it's tank.
Yes, 'rebuild kits' have stock jets. Dyno-Jet kits usually have an assortment of jets for the installer to choose from. And yes, most people think they need to rejet when they change exhaust systems, but it's just ignorance on the part of the consumer and promoted by the sellers of "performance" exhaust systems. Ignorance is the presumption that more fuel equals more power. Just the opposite is true. Power comes from the heat of the burn (BTU's). A rich mixture burns cooler and is easier to ignite. Thus, cold engines need a richer mixture to start. The hotter the engine is, the less fuel that is needed to generate the desired output. The phenomenon escalates until the engine burns up. The heat generated is controlled with the cooling system and air to fuel ratio. The richness of the mixture is controlled to maintain a heat level the engine and cooling system can absorb and dissipate. Make sense?
The exhaust system carries heat out of the engine. Changing the exhaust to a free-er flowing system allows more heat to be carried away from the engine, but only at high RPM. The amount of heat getting out of the engine at low RPM is relatively unaffected. So rejettng for a free flowing exhaust is usually only needed for high speed operation. General rule of thumb is to jet up two sizes on the main jet for a change to the exhaust and in the majority of cases, no change to the idle or mid-range settings are needed.
Changes to the intake affect the entire range of engine operation, but idle is usually compensated by simply readjusting the fuel screw and mid-range may be fine without change, but the main jet may need bumped up 4 sizes or more depending on the extent of modifications.
The stock jetting was a #38 pilot jet and 142 or 148 main jet depending on altitude. 142 for high altitude. These jets are adequate for normal operation, but a performance freak will adjust for optimum output at the altitude and air density in his locale of operation.
Is there anything else I can help you with?