[BlackSCRunner]

Like the title says, I'm just about out of the premix the seller gave me when I bought my bike a little while ago. I did some searching and found this link which shows the location of Sunoco stations in MA that sell their high octane Sunoco 260 GT100 AKA Cam2 race fuel.

http://www.sunocoinc.com/Site/Consumer/RaceFuels/260GT100Locations/Massachusetts.htm

Anyone have any other suggestions? I am in Boston, so finding somewhere close would be ideal. The closest Sunoco is 45 mins away. What about those octane boosters? The seller included a bottle (which I am assuming he had been running) but so far I've heard from at least one source that those things do nothing. Although, assuming he was using just that in 93 pump gas, the bike has run fine so far, but I'm also hearing as the weather warms I could run into problems if I don't use the standard 93/race fuel 50/50 mix. Any input from you guys would be appreciated. Dan Williams, you're not too far from me, where do you go?

Thanks Guys! :ride:

[Estevahn]

Av gas works fine too.

Uh oh! We're in deep shit now.

Sorry Fester! :worthy:

[2PLY]

Darn right!! Fester is gonna be all over this one.. :bonk:

If you have a local general aviation airport, go talk to the manager and see if they will let you buy 100/130 Low Lead Aviation Gas (AVGAS). Mix it 50/50 with pump premium, do NOT use it straight.. Burns too slow, meant for low RPM engines that pull a heavy load at high altitudes and low temperatures, but has worked well for me for 30 years.

I haven't seen it for years, but if the airport has 80/87 AVGAS, do NOT buy it! You need the 100/130 LL. My last purchase last week was $4.00 per gallon at Crest Airpark in Kent, WA

But check with the airport manager first. They risk losing their license to sell the fuel IF they alow someone to put it in a car that runs on the streets. And they DO NOT want to risk losing their license. :busted:

[redrider7202]

great... another fuel thread... u got the 01 beta right? i get confused on who has what... anyway... if it's anything like my 03 it can be jetted to run 93... but that black crap will run down the exhaust... and i believe it based on the muffler packing i pulled out. However, shy of doing that it will ping.

[BlackSCRunner]

I'm in Boston, so the local airport is Logan International, and I don't think they're selling fuel...I will run it on 93 for now, and maybe it has been jetted for that, but if I get pinging in the summer, I want to be prepared. I can certainly make the 45 min trip to Sunoco, but from what people are telling me this stuff smells terrible, and is difficult to store? So if I can find something closer that would be better. If I do make the trip to buy some, how should I store it? Standard plastic gas container? Store it separate, or mixed with 93? Store straight gas, or premix?

And I have the 2000 Beta....u were close :)

[redrider7202]

it's hard to keep them all strait... imc must have the 01 then. and trust me when i say if it was jetted for 93 u'd know...

as far as storeage, i just mix it at the pump into a metal gas can. i tossed some stabil in it before the winter... just to be safe.

Anyway, AV gas, http://www.airnav.com/fuel/local.html, take ur pick. you can back track to use ur actual area code, i just picked the first one i found for boston... shouldn't make much of a diff though.

[redrider7202]

oh, and if u go to one where the code doesn't start with a K it's a smaller airport, just an fyi

[1992yz125]

I'm in Boston, so the local airport is Logan International, and I don't think they're selling fuel...I will run it on 93 for now, and maybe it has been jetted for that, but if I get pinging in the summer, I want to be prepared. I can certainly make the 45 min trip to Sunoco, but from what people are telling me this stuff smells terrible, and is difficult to store? So if I can find something closer that would be better. If I do make the trip to buy some, how should I store it? Standard plastic gas container? Store it separate, or mixed with 93? Store straight gas, or premix?

And I have the 2000 Beta....u were close :)

Keep it in the metal drum that you buy it in and you'll be fine. I mix it with pump gas and premix immediately, just so I know that it's done. I use the Amsoil premix, which is nice, because it turns your gas a bright blue, so you always know if it's mixed...

And who cares how it smells? How much time do you spend standing behind your running bike? :excuseme:

[BlackSCRunner]

And who cares how it smells? How much time do you spend standing behind your running bike? :excuseme:

Most of my free time actually...:smirk:

Seriously though, I was thinking more regarding storage in my garage and fumes from the fuel while stored...

So it comes in a metal drum, and there is enough room to mix 50/50 with 93? EDIT: I think you meant buy a metal fuel container, bring it, fill it halfway, then fill the other half with 93...correct me if I'm wrong. Where's a good place to buy a metal gas can? I have about 6 plastic ones but no metal....Although I did pick up 4 22oz MSR fuel bottles today at REI for $13 a piece I figure 2 in the pack should be good, and 2 extras for a friend or just in case...

Oh and thanks for that link I think it will be easier to make the drive to Sunoco, the closest small airport is really no closer, and the closest large ones talk about pulling a fuel truck up to the plane...I don't think I need that.

How would I know if it was jetted for 93? So far I've only used the mix he gave me, which I'm guessing is 93 with that 104 octane booster I mentioned. So far it has run fine, but it's not very warm outside yet.

[treehopper]

Gasoline loses octane when stored in plastic. You should buy a 35 gallon steel drum if you want to store it more than awhile. There are places that clean and resell used drums.

[1992yz125]

Seriously though, I was thinking more regarding storage in my garage and fumes from the fuel while stored...

So it comes in a metal drum, and there is enough room to mix 50/50 with 93?

Fumes in general are not noticeable at all. It has a slight acidy smell, but nothing near as bad as regular pump gas.

As for cans, most places you go will probably sell race gas in 5, 10, or 55 gallon drums. I get a 5 gallon can, and fill up a plastic fuel can with 2 1/2 gallons of pump gas. Then I take it home, put the 2 1/2 gallons of pump gas into an old metal race gas can, and then fill the rest of it up with the race gas from the can that I just bought (is this making any sense?). That way I have a mix that is more or less 50/50 race gas and pump gas. I then shake that up, and pump the mix into the plastic can that I actually take on rides, and mark the mixed container "mixed" with a sharpie, so as to not get confused.

The nice thing about this method is that I only ever have maybe 1 or 2 gallons of gas in a plastic container at any given time. The rest of it is sealed away in a metal can.

[Dan Williams]

I buy the CAM2 (Sunoco) 110 at Haffners up in Haverhill on 125. You can buy it from the pump. Much cheaper then VP C-12.

I've been using the MSR fuel bottles for a couple of years now. I much prefer them then having a plastic gas can in the truck. I keep them in a sealed case like a Pelican case so they don't rattle around and it's easier to refill the bike from a 33oz fuel bottle then a 5 gallon jug.

[BlackSCRunner]

go to lowes and get you a gallon of xylene or toulene it will be in the paint thinner section. 15 to 18 dollars a gallon. mix it 30% xylene or toulene with premium pump gas. You will have 108 octane when your done. You can also add 1 mouth ball per gallon of your new mix fuel and get 110 octane. The moth balls must be 100% pure naphthalene.
Found this in another thread...anyone have any input?

[2PLY]

I buy the CAM2 (Sunoco) 110 at Haffners up in Haverhill on 125. You can buy it from the pump. Much cheaper then VP C-12.

I've been using the MSR fuel bottles for a couple of years now. I much prefer them then having a plastic gas can in the truck. I keep them in a sealed case like a Pelican case so they don't rattle around and it's easier to refill the bike from a 33oz fuel bottle then a 5 gallon jug.

I'm with Dan, but if you can run Premium auto fuel with no problems, don't read any further.

I live about 5 miles from a small General Aviation airport. I used to fly out of there in the local flying club. So anyway, I mix AVGAS, the 100/130 octane Low Lead blend with Premium Unleaded auto fuel at close to 50/50 5 gallons at a time.

Over the years, I've been buying the 1-Liter MSR aluminum bottles and now have 10 of them, so I do like Dan and store what I can in the bottles. They never leak and the local REI outdoor store sells replacement screw tops and gaskets for them.

I will sometimes add fuel stabilizer to the mix, but I use the type that is oil based from my local Stihl Dealer. They say there is a difference.

In most places, Premium Unleaded Auto fuel does not contain alcohol. I use that no matter what and avoid any gas that has alcohol in it.

There is still pressure from the FAA and Aircraft owners to keep alcohol out of Premium Unleaded auto fuel, because some years back, the FAA determined that some of the smaller planes could be certified to run auto fuel at a cost savings. Those aircraft were the ones that could burn the old 80/87 AVGAS but now most can use auto fuel AS LONG AS IT CONTAINS NO ALCOHOL. That is probably why we don't see the 80/87 AVGAS anymore.

With the extreme size of the pistons in those engines and the low RPM and extreme loading they endure, detonation can destroy them by blowing a hole in the top of the piston. So AVGAS is designed to burn very slow for these engines. Not made for high revving motors, but in Trials, our engines are most similar to aircraft engines with low RPM, high compression and high torque. Mix it with some Premium auto fuel to be safe.

[BlackSCRunner]

Thanks for the input, I've been reading a few fuel threads in other sections of TT as well and I think I will first try 93 premix and see how it goes, if I get pinging, I will try either sunoco, or a small airport...3.59 a gallon for 100LL in Stow, MA...

Question about pinging, when do I listen for it? Will it happen at idle mostly? I just want to make sure I don't damage my engine.

[2PLY]

Thanks for the input, I've been reading a few fuel threads in other sections of TT as well and I think I will first try 93 premix and see how it goes, if I get pinging, I will try either sunoco, or a small airport...3.59 a gallon for 100LL in Stow, MA...

Question about pinging, when do I listen for it? Will it happen at idle mostly? I just want to make sure I don't damage my engine.

This is for my bikes: When they get hot or at high revs and low throttle as in a 2nd or third gear climb where speed is needed but not full throttle. And when hot and just as I snap the throttle closed.

If your fan or water cooling fails, you will hear it just before the piston seizes when the engine over-heats.

I've never heard it at idle nor under load with medium to heavy throttle. If you don't know how to identify it, do what you can to learn. I would describe the sound as a rattle that sounds like a small hammer tapping very rapidly on the cylinder. You might have better luck learning how to identify the sound from a older car. The newer ones have knock sensors and electronic fuel injection and will do drastic timing and injection changes if they sense the knock (or ping).

Maybe there is a web site with a sound bite of what it sounds like.

[BlackSCRunner]

FWIW I ran the bike today with my own mixture of 93 + 104 octane booster (by stabil) at 80:1 and was listening for 'pinging' and didn't detect any...maybe I'm not seasoned to the sound, but I didn't hear any hammer knocking or anything like that...It ran fine as far as Im concerned, so that's not the issue, I just don't want to damage my engine...thoughts?

[Whatwasithinkin]

FWIW I ran the bike today with my own mixture of 93 + 104 octane booster (by stabil) at 80:1 and was listening for 'pinging' and didn't detect any...maybe I'm not seasoned to the sound, but I didn't hear any hammer knocking or anything like that...It ran fine as far as Im concerned, so that's not the issue, I just don't want to damage my engine...thoughts?


Knock or ping is prety noticable and out of place sound. other variables becides to low octane with high compression are air temp and load on engine. I raced MX back in the day, 1976 to 86. In 76 everything was air cooled. By 86 most all bikes had water cooling.

I ran 105/106 octane Cam 2 or Sunoco leaded race fuels in my bikes. Even on that stuff the air cooled bikes would knock and ping a bit when the weather got hot and sticky. It would increase even more at tracks like Southwick were traction was always 100% and has those killer steep hills. When the bikes turned to water cooling, I dont think I ever had the knock or ping happen again.

Knock and ping are 2 different things happening. And the sounds they make are what give them there name.

Knocking happens as the engine starts to overheat and the fuel starts to ignite on hot spots on the cylinder walls, cylinder dome or piston dome. As the piston goes threw its stroke if unburnt fuel ignites off a hot spot is causes the piston to rattle or vibrate. So basically the piston is slapping the skirts back and forth in a very quick movement. To much of that over an extended period will usualy crack or break the piston skirt off. The hot spots can also get to the point were they start to melt that spot and cause the ring to stick or break.

Pinging is a sound that comes from to low octane, too high compression, too much timing advance or a combination of all that lead to excess heat in the cylinder. Its been my experience that excess pinging ends up burning the sparkplugs electode away or even worse it can burn hole in the piston. The spark plug will act just like a plasma cutter and burn right threw the piston dome. Under alot of heat and under a heavy constant load on the engine, this can happen in just a few minutes with an aluminum piston.

and i forgot to add that both knock/ping wont happen at idle, both start as the engine becomes under load. Both may continue as the engine winds back down to idle, but that would be a rare event. Generally once you back out of the throttle they both stop happening.

[2PLY]

My rattle at high rev hill climbs and low throttle in my 04 300 Pro GG sounds like it's running too lean in the needle jet or combination pilot and needle. What has puzzled me is that my 07 300 Raga and the 04 300 Pro have the same Kehin carb jetted exactly the same.

However, this weekend, I needed to replace the radiator fan in the 04 and decided to add one 1mm thick de-compression spacer to see if that would help and to soften the kick starter since this is my primary loaner bike and the kick start lever is starting to bend. I have never had the head off on this bike and though I was pleased with the lack of carbon build-up from the gas/oil mix over the last 5 years, I found some dings in the top of the piston to one side and corresponding dings in the head. Looks like something went through the cylinder at some time long ago.

The resulting sharp tips to each ding could easily account for hot spots that could have contributed to my "ping" problem in that bike. However, since I also added the head spacer, I might not be able to confirm that.

Next, I'm going to test running the bike now on 92 octane Premium Unleaded Auto Fuel. It's still plenty strong on the power end and I don't even notice any loss in power. It was a $38 mod that took 20 minutes to do.

[Whatwasithinkin]

My rattle at high rev hill climbs and low throttle in my 04 300 Pro GG sounds like it's running too lean in the needle jet or combination pilot and needle. What has puzzled me is that my 07 300 Raga and the 04 300 Pro have the same Kehin carb jetted exactly the same.

However, this weekend, I needed to replace the radiator fan in the 04 and decided to add one 1mm thick de-compression spacer to see if that would help and to soften the kick starter since this is my primary loaner bike and the kick start lever is starting to bend. I have never had the head off on this bike and though I was pleased with the lack of carbon build-up from the gas/oil mix over the last 5 years, I found some dings in the top of the piston to one side and corresponding dings in the head. Looks like something went through the cylinder at some time long ago.

The resulting sharp tips to each ding could easily account for hot spots that could have contributed to my "ping" problem in that bike. However, since I also added the head spacer, I might not be able to confirm that.

Next, I'm going to test running the bike now on 92 octane Premium Unleaded Auto Fuel. It's still plenty strong on the power end and I don't even notice any loss in power. It was a $38 mod that took 20 minutes to do.

I was looking at those pics. Something went threw the engine at some point. What ever it was, it was small, so it didnt cause terminal damage. When Ive seen something like that out of my own engines, its usualy a shaving of something from the lower end that happened the first time the engine got realy spun up. Sometimes as the engine got broke in and realy hammered on for the first time, the rod would stretch and catch the case and shave off a little material from one or the other and then that finds its way up threw a transfer port. Just a guess. Only way to confirm is by pulling the jug off and look for shiney spot on the rod and matching worn spot on the case.
http://home.comcast.net/~jc-long/trials-misc/5-year-head-300pro.jpg

If it was damage from a hotspot, it would look like a small crater with fine particles burnt in around it, almost looking like welding slag.

But it would appear from your sparkplug that you are running a bit lean. At least it appears that the plug is a little light. The small amount of wet sludge is normal in the T style heads. Most 2 stroke engine manufactures went to the T style head design back @ 2000. Not for performance , but to meet emission standards. That sludge is the result of that design and how the fuel combusts inside the head.

What I dont see is a lot of wash on top of the piston. This may be that Im not familiar enough with the trials engine. I would guess that the basic trials engine is at idle a good bit of the time and only blipped and occasionally reved up to the higher rpms. That too would cause the sludgy build up.

[2PLY]

Yes, I know it's not from a hot spot because I can see the matching spots on the head and piston.
http://home.comcast.net/~jc-long/trials-misc/5-year-head-pits-300pro.jpg


http://home.comcast.net/~jc-long/trials-misc/5-year-piston-pits-300pro.jpg


But the only trama the bike has gone through was a self-destruct of a needle bearing on the clutch output shaft two months after buying the bike. But that is in the transmission.

And I did notice that the plug was a lighter color than I would like. I'm going to check it soon to see what the 1mm head spacer does.

And thanks for the insight. I appreciate the evaluation.

I think for now, I'll leave the barrel on and not disturb it, but I have a good photo record of the current spots and will check it later to see what happens from here. I took a dremel tool and smoothed out the sharp edges, so any new marks will stand out.

[Dan Williams]

Like **** through a goose. Something definately went through that cylinder and it weighed enough to not make it in a single cycle. $5 says it's still in your exhaust. It was also hard enough to leave a sharp impression in high silicon aluminum. Looks like steel to me.

Hmmm, you could get some putty and take an imprint with the head and cylinder together. Then you'd know what the piece looked like.

[Dan Williams]

Found this in another thread...anyone have any input?

YIKES! Why bother?

[Dan Williams]

Knock and ping are slightly different at a fundamental level. One is pre-ignition the other is detonation. Let me splain, no that take too long, let me sum up.

Pre-ignition is a condition where, due to a hot spot in the cylinder (bit of carbon, wrong plug, incomplete scavaging of hot gas) causes a secondary flame front in the mixture. This doesn't necessarily happen before the plug fires but can. This raises the pressure of the mixture faster then would occur with the normal flame front propagating out from the plug firing. Pre-ignition will cause a gradual rise in combustion chamber temperature stressing the components as pointed out earlier and can lead to the other condition detonation.

Detonation occurs when the air/fuel mixture is heated to such a degree that it spontainously burns creating a massive spike in pressure. This is the real nasty one that blows holes through pistons and breaks the mechanical stuff.

The reason the piston and cylinder head is shaped that way is to control the speed and pattern of the burn. As it travels out to the squish band the flame front accelerates due to the increase in pressure and temperature of the mixture. That's why the squishband is there. It keeps the local temperature of that last bit of mixture low enough and prevents shockwaves from the main combustion chamber burn from bumping the pressure. This controls the speed of burn of the mixture farthest from the ignition point.

Picture what happens when the ignition point is not where it's supposed to be and you can see the problem.

So pinging and knocking are really both the result of too rapid a rise in combustion chamber pressure. It's just the root mechanism and severity that vary. FWIW though octane is a fuel's resistance to detonation so there is a benefit to running good gas but once you've got a fuel that works good enough it's... well it's good enough and there's no significant advantage to a higher octane.

[2PLY]

Found this in another thread...anyone have any input?

Last time I heard, xylene and toulene are very nasty solutions to mess with. And I found out after using them to remove latex paint and other things from tile and other places in new houses. :banghead: But spare me the details, that was 30 years ago. :busted:

[Whatwasithinkin]

YIKES! Why bother?


yeah that whole paint additive to gas thing is good ol' internet snake oil. Lots of sites out there touting the benefits and just as many debunking them.

Best method Ive found, use the correct gas mixed with a quality oil and everything will be happy. Personally Ive always stayed away from octane boosters too. The only thing Ive seen them do is discolor plastic feul tanks and make the fuel lines brittle.

[BlackSCRunner]

thanks for the input guys, regarding the paint thinner stuff, i did some more research right after i posted that and ruled it out. I'm going to order some stainless steel gas cans online and make a trip to the sunoco. On a side note, is there any reason not to go stainless steel other than price? I have found a good deal on stainless gas cans only a little more than the standard steel ones (which I assume are galvanized?).

interestingly enough, I found the notes for premix from the seller, he indicates 53:1, where I have been running 80:1 on my mix. He also indicates 160:1 for the octane booster and I ran it a bit richer than that at more like 100:1

[FESTER]

funny cause i use 91 octane gas and my bike runs great,the only time it pings is when its really hot or just before it runs outta gas.i just think race gas is a hype m.t.c.

[2PLY]

funny cause i use 91 octane gas and my bike runs great,the only time it pings is when its really hot or just before it runs outta gas.i just think race gas is a hype m.t.c.


Fester, consider the altitude of your riding areas. It makes a BIG difference in octane requirements. Go to some higher altitude States like Colorado and you'll find the pump gas is 85 and 91 octane where here in Seattle, it's 87 and 92. You might have a similar situation near Tahoe and into Reno and down highway 395.

However, I've never been fond of "Race Gas" because I can never be sure what's in it. And 2-strokes don't fair well with any heavy use of lead as a booster and I have no idea what "other" chemicals they might use in its place.

I know that AVGAS is blended specifically for aircraft and their special needs for cold intake air at high altitudes and have additives to help improve storage, but I trust the quality of it. However, I would NOT run it straight because it is designed to burn very slow (very high octane). Most airports now only carry the 100/130 Low Lead version. That means it is suitable for engines that require from 100 to 130 octane fuel. My Gas Gas is listed as needing 95 octane at Sea Level.

The guessing part on my end comes from believing that if I mix it with Auto Fuel, I'll get a combination of both, higher octane and a little faster burn ability. Something inbetween the two. I could be wrong there, but what I'm SURE of is the quality of the fuel itself. :thumbsup:

[2PLY]

Last time I checked, The Importer for Gas Gas (Dale) uses AVGAS in his mix too. He told me that he uses it straight sometimes. However, he's a pilot too and that could be why we both lean toward using it.

I'm still waiting to meet a petro-chemical engineer that can tell me why or why not to use it. Just telling me to use it or not is not enough, I want to know the details. Maybe put my years of Chemistry and Physics in College to good use.