Just replaced burned piston on my 1965 Harley M-65 and don't want to do it again. Owners manual specifies 25:1 ratio with SAE 30 Harley-Davidson two-stroke oil, which may be real hard to find. What have others found for antique air-cooled 2 stroke motorcycles that are actually ridden?
pre-mix 2 stroke oil for M-65
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Burned piston doesn't sound as much like a lube/oil failure as a mixture problem...What do you mean by "burned"? Scored? That's from overheating (generally from running lean) as is a holed piston... What was the plug color when you pulled the head?
I am guessing you need to richen it up a bit...surprisingly, running a higher gas/oil ratio (like 40:1) makes the engine run a hair richer, you're getting more gas through the same jet at the same vacuum...
As far as oil, I would think that almost any of the modern lubes are far better than the oil that was available at the time the bike was built...I always liked Golden Spectro, and Bel-Ray, but my experience with 2 strokes is dated...
I am guessing you need to richen it up a bit...surprisingly, running a higher gas/oil ratio (like 40:1) makes the engine run a hair richer, you're getting more gas through the same jet at the same vacuum...
As far as oil, I would think that almost any of the modern lubes are far better than the oil that was available at the time the bike was built...I always liked Golden Spectro, and Bel-Ray, but my experience with 2 strokes is dated...
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Thanx for your reply. Piston was scored and seized, because of user error. My wife was participating in the True Grits 50cc Fun Run and forgot that running full-throttle on a 45-year old two-stroke could cause problems.
Their are now 2-stroke oils on market now, specifically for oil and water cooled engines. I'm looking for specific experiences.
Their are now 2-stroke oils on market now, specifically for oil and water cooled engines. I'm looking for specific experiences.
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I'd look for a leaking crank seal thats allowing it to suck air. Persoinally I like Torco GP-7 and I run it in all my air cooled 2 stroke stuff.
Any of the two stroke racing motor oils will have the highest level of protection.
Like Honda Hp2 or YamalubeR, these are 2 stroke premix oils and not injector oils.
If you need injector oil, Yamaha also has injector oil as does Kawasaki, and there are Dedicated injector oils, Like Belray SI-7.
Non injector 2 stroke oils offer the highest level of protection, but if using in an injector from an oil tank, you need injector oil.
ONe time I ran a 2stroke oil that could be used as injector oil or premix, but I discovered it didnt have the film strength needed for my application.
The HP2 is about the heaviest fim strength Ive seen in premix oil, yamahalubeR is the best cross with Cleanliness and protection. Belray SI 7 is about the cleanist injector oil with Protection.
Like Honda Hp2 or YamalubeR, these are 2 stroke premix oils and not injector oils.
If you need injector oil, Yamaha also has injector oil as does Kawasaki, and there are Dedicated injector oils, Like Belray SI-7.
Non injector 2 stroke oils offer the highest level of protection, but if using in an injector from an oil tank, you need injector oil.
ONe time I ran a 2stroke oil that could be used as injector oil or premix, but I discovered it didnt have the film strength needed for my application.
The HP2 is about the heaviest fim strength Ive seen in premix oil, yamahalubeR is the best cross with Cleanliness and protection. Belray SI 7 is about the cleanist injector oil with Protection.
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For an air cooled piston port my first choice would be Castrol A747. It's a castor/synthetic blend. It's thicker, at a 50 weight, but it will protect very well, especially at 25:1.
Lucas as some semi-synthetic oil that they claim is good for air cooled engines. It contains ash based additives that are suppose to be good for air cooled engines. The flash point is very low @ 180*F. I think that is too low. I personally wouldn't use Lucas in something I cared about. Look at the hardware stores for 2C oil used for leaf blowers and other air cooled engines.
Originally Posted By: Loobed
Lucas as some semi-synthetic oil that they claim is good for air cooled engines. It contains ash based additives that are suppose to be good for air cooled engines. The flash point is very low @ 180*F. I think that is too low. I personally wouldn't use Lucas in something I cared about. Look at the hardware stores for 2C oil used for leaf blowers and other air cooled engines.
Lucas has a low flash point because it's an injector oil. I'm pretty sure that's the solvents flashing off.
Lucas as some semi-synthetic oil that they claim is good for air cooled engines. It contains ash based additives that are suppose to be good for air cooled engines. The flash point is very low @ 180*F. I think that is too low. I personally wouldn't use Lucas in something I cared about. Look at the hardware stores for 2C oil used for leaf blowers and other air cooled engines.
Lucas has a low flash point because it's an injector oil. I'm pretty sure that's the solvents flashing off.
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