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does a 1971 cb175 require leaded fuel? also owners manual says premium fuel, 85 octane or higher, around here regular fuel is 87 octane, so which fuel to use?
 

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Funny you bring this up... I've been touting non-ethenhol fuels for years... I TOTALLY forgot about LEAD!
If the motor has hardened valves, seats, and guides.. I believe lead is not needed. Do not quote me.. this is just what I remeber when I drove a 67 mustang in high school (early 80s) and had to use lead additive when I filled up.
 

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My 450K6 and 500T run fine on regular gas with the original valves. I use non ethanol just because ethanol is so destructive.

I've had the 450K6 since about 1980 and the 500T since 1994.
 

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True .. these motors will "run fine" with current "unleaded fuel"... However without the presents of lead in the fuel, leadoxide is not created when burned. This was what lubricated the (non-hardened) valves, seats, and guides..
Now, this information is being dug up out of my head so I can't be held responsible for its accuracy..
pre-70s autos (I have NO info on motorcycles) were built with motors requiring "lead" in fuel. I have heard stories of motors running for years into the future on unleaded gas. I was not as fortunate, my straight 6 burned somevalves.. requiring head work..
I had been told (late 80s) that unleaded fuels had additives to a assist with valve train lubricarion... but this was a little to late... these vehicles were driven daily from the 70s into the late 80s without any "leadoxide" unless it was added by the operator each time. Also these "additives" were not available to the "public" untill late 70s early 80s... Think about what it would do to a motor..
Believe it or not.. the "powers to be" are doing this again with ethenhol in fuel ( destroying[crushing] cars from the inside out). The American people fell for the "clunker buy back" program in the early 2000s.. because the big 3s auto sales were crashing.. People that bought new cars (origional owners) were "recycling" their cars by having new motors and transmissions installed at a fraction of the price of a new car. I read a study when pres clinton was asked about his old 67 mustang. It had to do with environmental pollutants and one point I read (not exactly sure of percentages)..,"During the life of a automobile, 90% of the pollutants from that car that enters the environment IS WHEN IT IS MANUFACTURED...
So when people were swapping out drivetrains, "recycling" their cars.. this percentage was eliminated already no with the purchase of a new car...
The "clunker buy back" cars were destroyed at the dealer level..Fluids drained and a solvent was added to the motor untill the engine seized... these vehicles were totally "crushed".. parts weren't "picked" or recycled... This caused a HUGE problem in the "after market parts business as "cores" (motors, trans, master cylinders, brake calipers etc.) that were normally used or obtained were destroyed..
"Ripple effect"..
Now, "hard parts" are surviving .. but ehtenhol in fuel is destroying "soft" parts.. (hoses, "O" rings, gaskets)... and with EPA, and computer systems (EVAP).. just swapping out a poertrain won't be cost effective as it was before..
DAMN... sorry, for the rant..
so, do some research, test the "health" of your motor (compression-leak down)... with a low mileage bike and today's additives.. you should be fine ..
I do find these motors tune and run better with non ethenhol fuels..
Just my $.02
 

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This forum is full of people enjoying these bikes with original engines and using modern fuels without any valve problems.
 
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