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Newbies: Gas-oil mix, Spark Plug, Setting Points

PostPosted: Sun Jun 17, 2018 5:21 pm
by hennesse
Gas-oil mixture: 25 to 1 ratio
Use any commercial 2-stroke oil, or SAE 40 (that's what Harley 2-stroke oil was)
5.1 ounces of oil in 1 gallon of gas

Spark Plug: Champion H8 or H8C
(Autolite 216, AC 43LS, NGK 36L are similar)

Spark Plug Gap
Battery ignition: .025 - .030 (Model 125 and Model 165)
Magneto ignition: .040 - .045 (Hummer, Super 10, Pacer, Scat, Ranger, Bobcat)

Points Gap
Battery ignition: .020
Magneto ignition: .018

All models: Disconnect the spark plug wire before pushing the starter crank to get the points on the high point of the cam - it might just start !!! Better yet, remove the spark plug to make it easier to rotate the engine to get to the high point of the cam.

Magneto models - The upper set of points powers the ignition. The lower set of points powers the stoplight. The cam has two lobes, so you'll have to get the ignition points on the high point of the ignition cam. Later, get the stoplight points on the high point of the stoplight cam.

The points need to be cleaned periodically. Use a points file, a piece of 240-grit Wet-or-Dry sandpaper, or in a pinch, the striker from a book of matches. If the points are pitted - and they probably are - you should remove them and clean them up on the bench. If they're badly pitted or burned, it's time to get a replacement set (and get a new condensor while you're at it).


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The Service Manual contains complete dis/assembly instructions. If you don't have one, you really need one. Harley Part# 99444-93 is available from your local dealer. $40 gets you a Service Manual, a Parts Catalog, and much much more.

Re: Newbies: Gas-oil mix, Spark Plug, Setting Points

PostPosted: Fri Apr 12, 2019 1:54 am
by martinbrown12
You explained everything very will hope this will help me in the future, a few months ago I faced a lot of problems in a bike I had to take 3 times, Motorcycle Towing Service. thank you for this.

Re: Newbies: Gas-oil mix, Spark Plug, Setting Points

PostPosted: Tue Oct 11, 2022 12:22 pm
by sqrldader
Thanks for the info! does anyone use synthetic oil in the gas?

Re: Newbies: Gas-oil mix, Spark Plug, Setting Points

PostPosted: Tue Oct 11, 2022 12:48 pm
by troymessina
Yes, I think a lot of us do. I've read (I think here and on facebook group) that modern synthetics allow a 32:1 mix instead of 25:1.

Re: Newbies: Gas-oil mix, Spark Plug, Setting Points

PostPosted: Tue Oct 11, 2022 3:23 pm
by 250_Sprint
Remembering from my days on mopeds and no-peds, I switched to Bel-Rey synthetic 2-stroke oil. After decarbonizing and the switch to synthetic, I gained mpg AND mpg and did not leave a blue line identifying my path.
Synthetic did not leave a coat of oil on internal parts like Dino oil did so for long term storage or no-use, I would pour oil in the cylinder and rotate the engine. Upon reuse, she would smoke a little then no more smoke.
I put many miles on those 49.8cc 2-strokes without issues.