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I see that people use 91 or 94...but how about 104 or 110. we can get it around here and im just wondering if it would be of any benefit to use it.

Also I know about redoing all the bolts and flushing the tank and replacing the fuel line adjusting the needle, but where should i look as far as buying my first mods? and what should they be? My FF Cag should be here tomorrow. I got it for 250 Shipped off of ebay, im so excited i cant even wait.
 

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I don't see any benefit of running higher octane on these motors (above 94)... the compression ratio isn't high enough to make use of the high octane fuel...

There are many places to buy parts... depends on what you plan to do with your bike.... i.e. short technical tracks, top speed runs... let us all know what you want to do with your bike and we'll suggest from there..

cjmatt said:
I see that people use 91 or 94...but how about 104 or 110. we can get it around here and im just wondering if it would be of any benefit to use it.

Also I know about redoing all the bolts and flushing the tank and replacing the fuel line adjusting the needle, but where should i look as far as buying my first mods? and what should they be? My FF Cag should be here tomorrow. I got it for 250 Shipped off of ebay, im so excited i cant even wait.
 

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race gas allows the motor to run cooler. It is a MUST for running a AC 2 stroke in hot weather. Once dialed in, it WILL be faster and better throttle responce.
 

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But for the added cost is it going to be worth it? Probably not...

jsigone said:
race gas allows the motor to run cooler. It is a MUST for running a AC 2 stroke in hot weather. Once dialed in, it WILL be faster and better throttle responce.
 

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for me YES. I'm 210 and I can use any advantage I can over these 120lb riders:D

Plus here in San Diego it's pretty warm almost all yr long. The track we race at is near the desert and gets hot there as well. Averages in the 90*'s

Race gas burns slower so u end up using less of it as the day goes on. I'm usually at the track for 10 hours every sunday. A 5 gallon drum should last me a LONG time.
 

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race fuel

jsigone said:
race gas allows the motor to run cooler. It is a MUST for running a AC 2 stroke in hot weather. Once dialed in, it WILL be faster and better throttle responce.
You are completely wrong, race fuel does not run cooler .(not trying to sound mean) The higher the octane rating in fuel the harder it is for the fuel to ignite. That is why it is used in high compression motors to help stop pre-ignition. The other side effect of race (high octane) fuel is that it creates a longer flame front, or burn duration, this is one of the reasons it creates more power, but along with the longer burn duration comes more heat. In a two stroke racing application, you want to run the lowest octane rating you can without pre-ignition, or detonation. On really hot days, you are better off running more oil, and a bigger jet.

There are some new fuels out such as VP's C-12 that are a bit higher octane but are designed for 2 stroke motors, so they have several fuel additives, such as lead, and some other coolants to help run the bike cooler.

If you want I can point you to about half a dozen sites that will tell you the same thing.

In a Cag, run 91-92 pump gas at 32-36:1 with a good synthetic 2t oil like Motul or Redline, and jet a bit higher to compensate for the extra oil. Hell, that goes for almost any PB. This is a bit overkill, but better safe than sorry. I have been running my 10hp DM on this (though I have switched to the C-12 fuel) in Stockton with average temps in the 90-100s with out a single problem. Also this is the same fuel I recomend for use on all the a/c 4.2's that I have built for people. Have'nt had a single problem yet.
 

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Part 2

Here is just a quick bit of info from a racing site,

"TOO MUCH OCTANE CAN BE BAD!

Right now in the racing fuel business, there's a race to market the highest octane fuel that you can make. People relate the highest octane to "my motor is making more power." That couldn't be further from the truth.

One of the downsides to building a fuel with ultra-high octane is adding components that really slow down the flame front in the combustion process. You can get the flame front so slow, that the engine is now running in a too-rich condition. This takes away horsepower. So here you are, slowing down the flame front and getting rid of detonation, at the expense of losing horsepower.

I see this all the time at the track. I see engines running "heavy"; they're trying to tune it to lean it out, when actually the flame front is causing the problem."

This was taken from http://www.off-road.com/rick/gas-tech_part1.html , a well respected race builder.
 

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I used to run VP C-12 in my race quad (89 250r w/330 kit) but I can't see spending $50-60 dollars on gas to run my PB for the day... $10+oil is bad enough...
 

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Well I would first upgrade the airfilter and exhaust pipe. Thats a good mod that is better for your engine.
 

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Seeing your user name....And race your DM at Stockton....This can only be one guy....LOL....See you at the next race....:thumbsup:

Thanks for the good post...explaining about the fuel

DemonSpit said:
Here is just a quick bit of info from a racing site,

"TOO MUCH OCTANE CAN BE BAD!

Right now in the racing fuel business, there's a race to market the highest octane fuel that you can make. People relate the highest octane to "my motor is making more power." That couldn't be further from the truth.

One of the downsides to building a fuel with ultra-high octane is adding components that really slow down the flame front in the combustion process. You can get the flame front so slow, that the engine is now running in a too-rich condition. This takes away horsepower. So here you are, slowing down the flame front and getting rid of detonation, at the expense of losing horsepower.

I see this all the time at the track. I see engines running "heavy"; they're trying to tune it to lean it out, when actually the flame front is causing the problem."

This was taken from http://www.off-road.com/rick/gas-tech_part1.html , a well respected race builder.
 

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race gas work for me, simple as that. When riding the bike on pump gas w/ a 40:1 mix, over the duration of the ride, the engine gets hotter, the hotter it gets, the lower the power output and the effencancy is. Riding on race gas for the same amount of time in the same weather does not get AS hot and doens't loss it's effencancy. If your bike was Water cooled then you wouldn't have to worry about this power loss. But on these bikes and small heads, it does make a difference. When properly tuned for the higher octane (makes u run rich) by leaning it out, the bike will be faster. Race gas is less then $5 per gallon and that should last u at least 2 sessions of hard riding.
 

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Again you fail to see the point, these bikes get their lubrication through the oil in the fuel, so by already running 40:1, and leaning out your fuel mixture by way of jetting, you are again going to run into the same problems. Also these bikes, Cags or otherwise were never intended to run for more than 15-20 min. at a time (thats not to say they are not capable) but not intended. You can obviously do what you like with your bike, and if you are getting good results, great, but by providing wrong information to the masses "race fuel runs cooler" you are doing them an injustice. The majority of the people that choose to run race fuel without the details of what will happen, will only cost them an engine seizure in the long run.

And the question was what are the benefits? not what works for you.
 

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sorry I don't know all the guru stuff bout the gas nor how it effects my bike. I'm just going with what works and still trying to understand how these bikes work. A buddy of mine filled up my tank w/ 103oct and I felt a nice diffence w/o any type of jetting changes and now here I am running race gas and trying to tune around it. Some can't afford $5 / gallon... I can and I'm use to using this stuff in my turbo cars. Race gas is funner when u have a big turbo involved :D
 

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quote
"In a Cag, run 91-92 pump gas at 32-36:1 with a good synthetic 2t oil like Motul or Redline, and jet a bit higher to compensate for the extra oil. Hell, that goes for almost any PB. This is a bit overkill, but better safe than sorry. I have been running my 10hp DM on this (though I have switched to the C-12 fuel) in Stockton with average temps in the 90-100s with out a single problem. Also this is the same fuel I recomend for use on all the a/c 4.2's that I have built for people. Have'nt had a single problem yet."

Wow I must really be in for something,I run 50:1 /110 race fuel in our DMs and on the lean side of the street :rolleyes: .Hell,I was thinking of running 60:1 with 90% motul and 10% alky cylinder lube as oil.Think of the explosion that's gonna make:eek: Oh the humanity.


Tom
 

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Like I said, it's a bit overkill, but I would rather have my bike last a little longer between top ends then chewem up every few races. I noticed when I went from 105 back to around 95ish (the C-12) the bike was running about 20-30 degrees cooler over the duration of the race. Also keep in mind that I weigh in at 215 lbs. Not exactly a real svelte rider. I know alot of guys that run 50:1 with higher octane fuels, an they seem to eat up quite a few piston/cylinder kits a year. Hell, I know a few people that run 100:1 and put a fresh ring on every race day.

Its all about what works in each situation, there are so many variables to consider when tuning a bike, your regions weather, rider weight, how the bike is set up (spark gap, coil gap, cylinder gasket, ect.), what bike you have (proddy, open, 4.2, ect.) The above is just a fool proof combo, I have been riding it all season with only a single ring change in a season and a half and I seem to be running first in points in proddy at Stockton, so there must be something to it.
 

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"Like I said, it's a bit overkill, but I would rather have my bike last a little longer between top ends then chewem up every few races. I noticed when I went from 105 back to around 95ish (the C-12) the bike was running about 20-30 degrees cooler over the duration of the race. Also keep in mind that I weigh in at 215 lbs. Not exactly a real svelte rider. I know alot of guys that run 50:1 with higher octane fuels, an they seem to eat up quite a few piston/cylinder kits a year. Hell, I know a few people that run 100:1 and put a fresh ring on every race day.

Its all about what works in each situation, there are so many variables to consider when tuning a bike, your regions weather, rider weight, how the bike is set up (spark gap, coil gap, cylinder gasket, ect.), what bike you have (proddy, open, 4.2, ect.) The above is just a fool proof combo, I have been riding it all season with only a single ring change in a season and a half and I seem to be running first in points in proddy at Stockton, so there must be something to it."

It all in personal preference,our 10 hp bike has just about a year on the motor,only raced,and I haven't had to do a thing to it,besides seals.The rider is 180 + lbs and we are in FL.The bike is as strong as any out there.The opens are a whole different ball of wax,can't really compare them to this.

The higher octane fuel doesn't show any difference in dyno readings,this has been proved several times,the race fuels in my opinion seem to cumbust better and more completely than pump fuels.The 50cc motor we just received was run on pump fuel and it ran like crap till it was changed to the race fuel.It may be overkill but ,in my experiences with it ,you can't beat it.


Tom
 

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New Pocketbiker POV...

I'm just building my pocketbike. I am running ERC A-8C 120 octane race fuel. It is the fuel I am running in my 1994 RS125. I run that fuel because the specific gravity keeps the castor oil from seperating as quickly as it does in other fuel. I'm forced to run leaded fuel/castor oil in my RS, so I'm forcing the expensive stuff into my cheapo bike. It does'nt seem to care. For me, its just a good way to burn my old fuel.
I'm going out to put the walbro carb and new pipe on the thing right now. Wish me luck, ADA did'nt send any instructions with the carb.....
Fun times!
 
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