You helped me so much with my shock setup on my Piner I've got a question about fuel. What do you put in your bikes? Unleaded reg. or a higher octane? There is a racing shop here that sells Sunoco Racing Fuel that is still a leaded fuel that is 114 octane. I picked some of this up and mixed it with Belray Premix, hopefully this willbe ok. Its been a long time since I've mixed up any fuel.
Thanks, Rich
richard j allison
Rich,
this is only my preference. I use 50/50 CAM 2 purple and high-test pump gas.
Lew Mayer
105 octane leaded from the speed shop and golden spectro 50:1 in both my 72 Piners Dennis D
One word of caution: Heat If you are running anything over 100 octaine, have a close bore and you are a fast rider you could have problems. Please I do not want to debate this, but it is my thoughts and believe me I have accesses to any level of fuels that are made. Just my take.:)
Ron Carbaugh
I am running 105 with maxim super m 40/1 with no problems. I wish I could find cam 2 fuel here.I used it in my 430 Husky in Charleston and I cut it with 93 unleaded.It would FLYYYY
Thomas Carmichael
With all due respect to the riding abilities of everyone in this group (specially guys like "Smokin" Tom Benolkin): Does octane really mean that much? I know I'm not even close to the potential of my bikes running straight gas.
Just for the record, I use Spectro synthetic mixed 50:1 and premium pump gas from the same Shell station every time. I've never had a problem, my plugs run clean and I'm pretty sure my jetting will remain the same with the same gas.
I wasn't as concerned about the octane as I was about the leaded unleaded issue. If unleaded works just as good as the leaded racing fuel I will run the pump gas mainly because it is a lot cheaper.
thanks
richard j allison
My Jackpiner manual says to use a min. of 95 octane. I assume the same for others and with conservative jetting/timing.
It ran fine on half and half 100LL aviation fuel and pump 93. I never tried straight pump premium because the highest I could get was 93 and I'd rather not cook an engine.....jackpiner pistons are rather hard to come by. I wouldn't use straight aviation fuel either, it's made for very diferent operating conditions. It only costs about $3.50 a gallon versus $6+ for race fuel. I run this in all my bikes, vintage modern, and modern trials, I just vary the oil ratio. (Maxima K2 synthetic at 50:1 for mx/trail riding up to 80:1 for trials)
Frank
I used to run a gallon of VP c12 (112 octane)to 2 gallons of premium. It didn't run as good and I got some fouling plugs with lead deposits.
deleted
Merlin,
I am somewhat familiar with Nitromethane and it's properties, but I can assure you it isn't the only thing that will destroy a engine when it comes to FUEL. And piston clearance (tight? as you stated it) has more to do with fuel used because of different octanes can create more heat than others and heat on a close tolerance bore to piston clearance can cause a engine to seize. But I do agree with you on the "stupidity factor" and even some of the best have been fooled by this phenomenom[B)].
Ron Carbaugh
I would think that a higher octane would burn slower(hence the advanced timing on performance engines)so therefore would actually help keep an engine cooler if the engine is not built to the max. Am I thinking wrong here? and why?
Lew Mayer
What a great post Ron! the stupid factor also sometimes equates to ask a few questions, and to never be afraid.......I tend to shy away from the following mixture: 101 unleaded mixed 50/50 with 91 pump 40:1 Maxima 927...Oh yes Swaintech the piston..Teddy, where are you?
Tom...
Lew,
There is a lot of people on both sides of that argument which includes some of my closest and respected friends. All I can say is I will rest on what I have seen on the same engines run on the different octaines of fuel(gasoline). The best I have found run in a test lab at a Oil/Gas Refinery was around 98 octaine rating with aircooled 2 stroke engines with Blenzoil/Blendzine oil at 32:1. I have never had a seizure with this type of mixture with a air cooled 2 stroke engine.
This is just a forum of what we think so that is my take. I really don't put a lot of stock in slow burn or fast burn as long as I don't have detonation, hot spots or some type of lean conditions caused by other factors such as carburetion from changine of altitude. I know this is getting to be an out of control post so I am going to give it a rest for tonight....ZZZZZZZZZZZZ.[:0]
Ron Carbaugh
OK, my turn. I've spent a lot of time talking to various fuel and oil people about two strokes, and after weeding out the information that I really didn't need to know, here's what I learned. The octane rating of a gasoline, is purely a rating relative to the fuel's ability to control detonation. Detonation can be caused by a number of things, but in race engines, compression and ignition timing are the two most common contributors.
Sachs engines in stock form, are fairly mild, and as such, do not need race fuels. Just to be on the safe side, a high test pump gas should be used. There is one factor there, that you do need to pay attention to, and that is the alcohol content of the gas. Basically, you don't want a pump gas that has alcohol in it, if possible.
If you've pumped up your compression, then you may need to consider some race gas. During the Penton era, we never (to my knowledge) ran any race fuel, and normally, didn't even use high test gas. But, with a few exceptions, we were using stock heads. We did have some cylinder work done to the engines, but the heads were pretty much stock.
The KTM engines, are another story all together. KTM has a history of going after horsepower by using high compression. And this is only good, when you're "riding a dyno". When Carl Cranke built engines for team members, he would actually lower the compression along with doing the port work. These engines were some of the best running engines in the world. Two times during Carl's tenure at Penton Imports, people from KTM took top ends and pipes that he'd worked over, back to the factory for their people to look at and work from. And in both instances, the compression of these engines had been actually reduced instead of increased.
With these engines, with stock compression, it might not be a bad idea to use an octane rating around 100 to 105 in order to keep them cool. However, back in the day, we still used just pump gas in them, and I don't remember a lot of trouble.
Another very important factor with regard to the compression level, is head design. KTM had a very good handle on head design, which is probably why they were able to get away with the compressions that they did.
Another factor to be considered, is the oil mix ratio. Whenever you mix oil with the gas, it actually drops the octane rating. We always used the Hi Point Concentrate (today's Golden Spectro, exactly the same formula as it was in 1968!) at the ratio of 64:1. Why such a goofy ratio? 10 oz. of oil to 5 gallons of gas. I do remember some times, if the bikes were going to be used hard in sand, that we'd go to 4 gallons, which dropped the ratio to around 51:1.
You'll notice, that with those ratios, the octane wouldn't be lowered nearly as much as if you would be mixing the oil at 30 or 40 to 1, so maybe that's why we didn't have trouble with the compression.
As a final note regarding the Golden Spectro. All through my son's racing career with his Kawasaki mini's and 125's, I used Golden Spectro. I did drop the ratio though, because in top level motocross, the engines are used a lot harder than in vintage racing (with some exceptions, I'm sure) or off road racing. And I never had an engine failure that could be attributed to the oil.
I hope this has provided some insight and advice.
Dane
I miss the days of just pulling up to the Sunoco Pump and mixing your blend right there. I tuned for a few young racers in the 70's who were much faster than most of us now and that fuel was perfect. Anything over 98 octane is just a waste of money. Just my thoughts!
Donny Smith
deleted
Hey Tom...(DKWRacer) In an earlier post you said "...I tend to shy away from the following mixture: 101 unleaded mixed 50/50 with 91 pump 40:1 Maxima 927...."
Is there something about Maxima 927 that I should know? Its one of the few oils I have to choose from at my local bike shop. No one around me carries Golden Spectro...
Steve
Maxima 927 is a semi-synthetic blend of castor, synthetic, and possibly normal oils with additives that keep everything from seperating. It doesn't cause ring sticking as normal(100%) castor may but smells like the real thing. Sweet! The K2 that I mentioned is Maxima's best 100% synthetic.
50:1 with 927 may be too thin a mixture for longest engine life, it is a blend. Castor is usually mixed at heavier ratios than normal oils anyway.
I don't hesitate to use K2 at 50:1 in any air-cooled bike......if jetting is correct and timing isn't too far advanced. In modern water-cooled trials bikes we usually mix a 100% synthetic oil at 80:1, some use 100:1. Typically our bikes run over 5 years putting a lot of hours on them practicing, in competition, and ripping from section to section, before they need rings or bearings. That says a lot for modern oils at light mix ratios.
Looking at the posts after my 1st, I seem to have been declared an idiot. My statement was that min. octane requirement in my Penton manual was 95 for the 175. You can't buy 95 where I live. We tend to jet our bikes, in the sake of more power, a little leaner than factory settings. We also may advance the timing a smidgen to get more power. More power=more heat add too low octane and we get detonation, shortened engine (rod, bearings and possibly piston) life, possibly a heat sezure "meltdown".
My GasGas 280 pings like crazy on 93 pump gas, GasGas recommends 95 octane. I could never retard the timing enough and rejet to get pump 93 to not ping. It runs fine at 95+ octane.
The cheapest 95 I have been able to create is the 100 LL and 93 mix. 100LL has little lead compared to leaded race fuels. I don't get any lead fouling on my plugs with it like I got with VP110, VP c4 (112), and other leaded race fuel blends.
Each to his own. I love America!
Frank
Frank......In your opinion....do you see anything wrong with mixing Maxima 927 @40:1 with the high octane pump gas for my 77 400 GS6?
Thanks for the input
Steve
Steve, I realize I stuck 50:1 in where I meant 40:1 on the 927.
IMO,[:0] I know it's not much difference between 32, 40, and 50:1 but I'd err towards 32:1 (4 oz/gallon) with the 927 if I were racing it. Oil costs less than motor rebuilds! I have no problem with the oil itself.
I'm pretty sure straight castor usually gets mixed at 24-32:1, I run synthetics at 50:1, therefore with a blend I'd lean towards the heavier mix.
I have heard, don't know how right they were, that the "927" stood for 9 parts synthetic to(2) 7 parts castor or vice-versa.
Frank
deleted
I run Golden Spectro at 50-1 with 93 octane pump gas in all my bikes, lawn mower, weedeater, chainsaw, and leaf blower. I'm not an expert rider or a chemist but with no top end failures in 25 years of using it I think I'm sold on it.
Dennis Jones
.......no problem,why try to enlighten those that wish not to be?????......
As I said earlier in this thread, I've been using Specto synthetic in my bikes the last 3 years with good success. Is Specto another brand of Golden Spectro?
Rich,
this is only my preference. I use 50/50 CAM 2 purple and high-test pump gas.
Lew Mayer
105 octane leaded from the speed shop and golden spectro 50:1 in both my 72 Piners Dennis D
One word of caution: Heat If you are running anything over 100 octaine, have a close bore and you are a fast rider you could have problems. Please I do not want to debate this, but it is my thoughts and believe me I have accesses to any level of fuels that are made. Just my take.:)
Ron Carbaugh
I am running 105 with maxim super m 40/1 with no problems. I wish I could find cam 2 fuel here.I used it in my 430 Husky in Charleston and I cut it with 93 unleaded.It would FLYYYY
Thomas Carmichael
With all due respect to the riding abilities of everyone in this group (specially guys like "Smokin" Tom Benolkin): Does octane really mean that much? I know I'm not even close to the potential of my bikes running straight gas.
Just for the record, I use Spectro synthetic mixed 50:1 and premium pump gas from the same Shell station every time. I've never had a problem, my plugs run clean and I'm pretty sure my jetting will remain the same with the same gas.
I wasn't as concerned about the octane as I was about the leaded unleaded issue. If unleaded works just as good as the leaded racing fuel I will run the pump gas mainly because it is a lot cheaper.
thanks
richard j allison
My Jackpiner manual says to use a min. of 95 octane. I assume the same for others and with conservative jetting/timing.
It ran fine on half and half 100LL aviation fuel and pump 93. I never tried straight pump premium because the highest I could get was 93 and I'd rather not cook an engine.....jackpiner pistons are rather hard to come by. I wouldn't use straight aviation fuel either, it's made for very diferent operating conditions. It only costs about $3.50 a gallon versus $6+ for race fuel. I run this in all my bikes, vintage modern, and modern trials, I just vary the oil ratio. (Maxima K2 synthetic at 50:1 for mx/trail riding up to 80:1 for trials)
Frank
I used to run a gallon of VP c12 (112 octane)to 2 gallons of premium. It didn't run as good and I got some fouling plugs with lead deposits.
deleted
Merlin,
I am somewhat familiar with Nitromethane and it's properties, but I can assure you it isn't the only thing that will destroy a engine when it comes to FUEL. And piston clearance (tight? as you stated it) has more to do with fuel used because of different octanes can create more heat than others and heat on a close tolerance bore to piston clearance can cause a engine to seize. But I do agree with you on the "stupidity factor" and even some of the best have been fooled by this phenomenom[B)].
Ron Carbaugh
I would think that a higher octane would burn slower(hence the advanced timing on performance engines)so therefore would actually help keep an engine cooler if the engine is not built to the max. Am I thinking wrong here? and why?
Lew Mayer
What a great post Ron! the stupid factor also sometimes equates to ask a few questions, and to never be afraid.......I tend to shy away from the following mixture: 101 unleaded mixed 50/50 with 91 pump 40:1 Maxima 927...Oh yes Swaintech the piston..Teddy, where are you?
Tom...
Lew,
There is a lot of people on both sides of that argument which includes some of my closest and respected friends. All I can say is I will rest on what I have seen on the same engines run on the different octaines of fuel(gasoline). The best I have found run in a test lab at a Oil/Gas Refinery was around 98 octaine rating with aircooled 2 stroke engines with Blenzoil/Blendzine oil at 32:1. I have never had a seizure with this type of mixture with a air cooled 2 stroke engine.
This is just a forum of what we think so that is my take. I really don't put a lot of stock in slow burn or fast burn as long as I don't have detonation, hot spots or some type of lean conditions caused by other factors such as carburetion from changine of altitude. I know this is getting to be an out of control post so I am going to give it a rest for tonight....ZZZZZZZZZZZZ.[:0]
Ron Carbaugh
OK, my turn. I've spent a lot of time talking to various fuel and oil people about two strokes, and after weeding out the information that I really didn't need to know, here's what I learned. The octane rating of a gasoline, is purely a rating relative to the fuel's ability to control detonation. Detonation can be caused by a number of things, but in race engines, compression and ignition timing are the two most common contributors.
Sachs engines in stock form, are fairly mild, and as such, do not need race fuels. Just to be on the safe side, a high test pump gas should be used. There is one factor there, that you do need to pay attention to, and that is the alcohol content of the gas. Basically, you don't want a pump gas that has alcohol in it, if possible.
If you've pumped up your compression, then you may need to consider some race gas. During the Penton era, we never (to my knowledge) ran any race fuel, and normally, didn't even use high test gas. But, with a few exceptions, we were using stock heads. We did have some cylinder work done to the engines, but the heads were pretty much stock.
The KTM engines, are another story all together. KTM has a history of going after horsepower by using high compression. And this is only good, when you're "riding a dyno". When Carl Cranke built engines for team members, he would actually lower the compression along with doing the port work. These engines were some of the best running engines in the world. Two times during Carl's tenure at Penton Imports, people from KTM took top ends and pipes that he'd worked over, back to the factory for their people to look at and work from. And in both instances, the compression of these engines had been actually reduced instead of increased.
With these engines, with stock compression, it might not be a bad idea to use an octane rating around 100 to 105 in order to keep them cool. However, back in the day, we still used just pump gas in them, and I don't remember a lot of trouble.
Another very important factor with regard to the compression level, is head design. KTM had a very good handle on head design, which is probably why they were able to get away with the compressions that they did.
Another factor to be considered, is the oil mix ratio. Whenever you mix oil with the gas, it actually drops the octane rating. We always used the Hi Point Concentrate (today's Golden Spectro, exactly the same formula as it was in 1968!) at the ratio of 64:1. Why such a goofy ratio? 10 oz. of oil to 5 gallons of gas. I do remember some times, if the bikes were going to be used hard in sand, that we'd go to 4 gallons, which dropped the ratio to around 51:1.
You'll notice, that with those ratios, the octane wouldn't be lowered nearly as much as if you would be mixing the oil at 30 or 40 to 1, so maybe that's why we didn't have trouble with the compression.
As a final note regarding the Golden Spectro. All through my son's racing career with his Kawasaki mini's and 125's, I used Golden Spectro. I did drop the ratio though, because in top level motocross, the engines are used a lot harder than in vintage racing (with some exceptions, I'm sure) or off road racing. And I never had an engine failure that could be attributed to the oil.
I hope this has provided some insight and advice.
Dane
I miss the days of just pulling up to the Sunoco Pump and mixing your blend right there. I tuned for a few young racers in the 70's who were much faster than most of us now and that fuel was perfect. Anything over 98 octane is just a waste of money. Just my thoughts!
Donny Smith
deleted
Hey Tom...(DKWRacer) In an earlier post you said "...I tend to shy away from the following mixture: 101 unleaded mixed 50/50 with 91 pump 40:1 Maxima 927...."
Is there something about Maxima 927 that I should know? Its one of the few oils I have to choose from at my local bike shop. No one around me carries Golden Spectro...
Steve
Maxima 927 is a semi-synthetic blend of castor, synthetic, and possibly normal oils with additives that keep everything from seperating. It doesn't cause ring sticking as normal(100%) castor may but smells like the real thing. Sweet! The K2 that I mentioned is Maxima's best 100% synthetic.
50:1 with 927 may be too thin a mixture for longest engine life, it is a blend. Castor is usually mixed at heavier ratios than normal oils anyway.
I don't hesitate to use K2 at 50:1 in any air-cooled bike......if jetting is correct and timing isn't too far advanced. In modern water-cooled trials bikes we usually mix a 100% synthetic oil at 80:1, some use 100:1. Typically our bikes run over 5 years putting a lot of hours on them practicing, in competition, and ripping from section to section, before they need rings or bearings. That says a lot for modern oils at light mix ratios.
Looking at the posts after my 1st, I seem to have been declared an idiot. My statement was that min. octane requirement in my Penton manual was 95 for the 175. You can't buy 95 where I live. We tend to jet our bikes, in the sake of more power, a little leaner than factory settings. We also may advance the timing a smidgen to get more power. More power=more heat add too low octane and we get detonation, shortened engine (rod, bearings and possibly piston) life, possibly a heat sezure "meltdown".
My GasGas 280 pings like crazy on 93 pump gas, GasGas recommends 95 octane. I could never retard the timing enough and rejet to get pump 93 to not ping. It runs fine at 95+ octane.
The cheapest 95 I have been able to create is the 100 LL and 93 mix. 100LL has little lead compared to leaded race fuels. I don't get any lead fouling on my plugs with it like I got with VP110, VP c4 (112), and other leaded race fuel blends.
Each to his own. I love America!
Frank
Frank......In your opinion....do you see anything wrong with mixing Maxima 927 @40:1 with the high octane pump gas for my 77 400 GS6?
Thanks for the input
Steve
Steve, I realize I stuck 50:1 in where I meant 40:1 on the 927.
IMO,[:0] I know it's not much difference between 32, 40, and 50:1 but I'd err towards 32:1 (4 oz/gallon) with the 927 if I were racing it. Oil costs less than motor rebuilds! I have no problem with the oil itself.
I'm pretty sure straight castor usually gets mixed at 24-32:1, I run synthetics at 50:1, therefore with a blend I'd lean towards the heavier mix.
I have heard, don't know how right they were, that the "927" stood for 9 parts synthetic to(2) 7 parts castor or vice-versa.
Frank
deleted
I run Golden Spectro at 50-1 with 93 octane pump gas in all my bikes, lawn mower, weedeater, chainsaw, and leaf blower. I'm not an expert rider or a chemist but with no top end failures in 25 years of using it I think I'm sold on it.
Dennis Jones
.......no problem,why try to enlighten those that wish not to be?????......
As I said earlier in this thread, I've been using Specto synthetic in my bikes the last 3 years with good success. Is Specto another brand of Golden Spectro?
I always liked to use the cheap stuff and jetted the engine that way. The simple reason being that Netra always runs fuel stops into these poor Mom and Pop convenient stores with 6 month old 93 octane, so the bike runs like crap the rest of the Enduro anyway !! Theres got to be a happy medium. heck running tired fuel sure beats pushing the dang thing up a hill !!
The things we do on sunday...
Raymond
Down East Pentons
Sorry Steve, I meant to say that I do not, shy away from that mixture.
But this post brings regional concerns, to be shared amongst friends.. Gas is gas, but then again, maybe it's not...Tom...
Steve,
Do the bike shops around you carry the Maxima Super M?
It works well with pump gas. Dwight recommended it to us for our small bores and it has held up well in both the 175 KTM engine of my sons and my 175 hybread.
I had very good luck with 100 LL on the 79 400 we restored in 91 and Knudson was using it in the 250 that was doing so well in the nationals. I added an extra base gasket on the Piner of my sons so we can use pump 93 oct. I could not tell any difference in performance on his 175 with the extra .010 gasket other than it was a little easier to start
Chuckle chuckle!
I'm at sea level + 183 feet( highest point around here) and had no fuel boiling problems in in the summer (90 + degs and 90+ humidity). Unless I was flat tracking or Road Racing I would add an extra Base gasket and use pump gas. Its a whole lot cheaper and we don' t notice any difference in the woods. The bike runs cooler , it's easier to start and it should last longer.
Can not resist this. Probably the best tested premix oils are your outboard motor oils.I have used them for years and never had any problems. I have had problems with some of the so/so trick oils.
Bob Brizzee
While I prefer another oil, I can attest that Bob's bikes run quite well...especially that 250 Mc5-it is a particularly stong one.
On the fuel note-Lynn Shoup has recommended 100LL and run it for years. Mike Helper has run it for 30 yrs. We discoverd Saturday that the Castor 927 was separating with the av gas. I am now using Golden Spectro at 50:1 and have jetted bike accordingly.
You can adjust with jetting and timing your bike to run on either, pump gas, av gas or race gas. The best thing about the av gas is that it is low lead- 100 oct, very consistent and inexpensive.
Also, at 100 oct the jetting is not far off pump gas jetting.
I have run pump and race before. Usually the pump worked fine-sometimes I had a bike that liked the race gas better-more timing leaner jetting. The air cooled open bike is one i had not encountered til now-so this is what I have found out so far with it. James
7" and 4" travel? Hmm-that makes 11" Hey! I can live with that.
Call me cheap, but I have been using Pennzoil outboard motor oils for better than 20 years, never had an oil related faliure. I try to use Shell 93 octane unleaded gas. Pennzoil burns very clean, no power valve problems in my 200 KTM with carbon build-up.
Rocket
OK you ask for it.....CHEAP[^]. Man this has been a long time coming since that comment about "two things come from Texas, Steers and $#%%#$". And as we say in Texas "every Dog has his day" I know I have had plenty. Thanks for the opening Big R.[:o)]
Ron Carbaugh
James, Steve
I think the kind of oil you use with LL is the key. Some oils may not work well at all with it. We have used Spectro since the early 70's and it has always done a great job with the small bores mixed with any gas we used. We switched the Maxium Super M because we are running super trapp spark arresters and spectro gums them up quicker than some of the newer oils.
John D.
Quotequote:Originally posted by James
While I prefer another oil, I can attest that Bob's bikes run quite well...especially that 250 Mc5-it is a particularly stong one.
On the fuel note-Lynn Shoup has recommended 100LL and run it for years. Mike Helper has run it for 30 yrs. We discoverd Saturday that the Castor 927 was separating with the av gas. I am now using Golden Spectro at 50:1 and have jetted bike accordingly.
You can adjust with jetting and timing your bike to run on either, pump gas, av gas or race gas. The best thing about the av gas is that it is low lead- 100 oct, very consistent and inexpensive.
Also, at 100 oct the jetting is not far off pump gas jetting.
I have run pump and race before. Usually the pump worked fine-sometimes I had a bike that liked the race gas better-more timing leaner jetting. The air cooled open bike is one i had not encountered til now-so this is what I have found out so far with it. James
7" and 4" travel? Hmm-that makes 11" Hey! I can live with that.
I crashed an WWI Aeroplane due to 927 Castor separation in AvGas. AvGas is highly not recommended for race fuel. It is designed for a relative low compression, low steady rpm , at higher altitudes. It is extremely high in Lead content. Much higher than MoGas ( auto fuel ) ever was.
You can have good luck mixing a couple gallons of AvGas to 3 gal of Mogas to make a higher octane fuel ( about 97 to 98 oct.) you don't need more than this. Use Maxima Super M. Mixes well and doesn't separate, burns clean. It just doesn't have the Castor smell. Just don't use straight AvGas. Too high an octane will cause the engine to run flat. Also AvGas can fool you. It will look like you are running rich but you will be lean. Beware.
Cher'o,
Dwight
Dwight Rudder
7 time ISDT / E medalist
8 time National Enduro Class Champion.