1972 Honda SL70 Fix-up

Discussion in 'Projects/Builds' started by SirNovak, Mar 11, 2019.

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  1. SirNovak

    SirNovak New Member

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    Hey all,

    New to the site. Just inherited a 72 Honda SL70 from my uncle. It's in relatively good shape although he left it out this winter in New England so shes got some rust and minor cosmetic issues, but no dings or dents or scratches. Currently she won't start, but engine turns over no problem. Think the battery is just toasted so I'm gunna order a new one.

    This isn't my first Honda. Couple years ago I had a 1971 CB350, so I'm a little familiar but it's been a while so I'm essentially starting from no knowledge.

    Hoping to have her up and running (and registered) by mid spring. Anybody who is familiar with this model please let me know, been having trouble finding info on it online for some reason compared to the 350.

    Anyway, Ill keep you all updated. Thanks for stopping by!
     

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  3. racerx

    racerx Administrator
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    Nice looking bike, a shame it sat out all winter after this many years of successful preservation. Best place to begin is checking for spark.
     
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  4. AtLarge

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    Welcome aboard. That one is definitely worth saving. Good luck!
     
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  5. SirNovak

    SirNovak New Member

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    Anyone know off the top of their head what kind of oil is recommended for this bike? Thinking of trying to track down an old manual or maintenance book for this thing since finding stuff online seems like a crap shoot.

    Also if anyone knows of any good YouTube channels that focus on older bikes like these please point me in the right direction!

    Also what do you guys use to charge your batteries? I bought a battery tender but it doesn't have the right hook ups for the tiny battery. Not sure how I'm gunna charge the one I just bought. Gunna go to Autozone tomorrow and see if they can help.

    Thanks!
     
  6. wanrep

    wanrep Active Member

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    Any "motorcycle specific" oil in 10w40 will work. Usually it'll have a SG or SH designation on the back.

    Take your battery with you to Autozoo and ask them for crimp terminals that'll plug into the terminals on the battery. Crimp some wire to them and attach the alligator clamps from your charger to the wires.
    Make sure your battery tender is set up for 6V.

    Oh yeh...red is +, blue is -, if it's a Yuasa.
     
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  7. SirNovak

    SirNovak New Member

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    Update!

    Took me all day, but I got her running!

    Put a new battery in, checked the spark, all that was fine. Noticed that the throttle wasnt turning, so when my buddy came over we took apart the carb a few times, blasted it clean, drained the fuel out of the tank, put some fresh gas in, and we finally got her to reliably start up. Put some air in the tires so I'm curious to see if they hold. But if they do it looks like she's good to go! Will be cruising with her in no time!

    Thanks for everyone's help! I'm sure I'll have more questions as I start to do more work on it.
     
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  8. SirNovak

    SirNovak New Member

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    Update time.

    Been working on the bike here and there when I have time. Seems to be running really well so far. Only thing I'm noticing is trouble shifting back to neutral it either stays in first or kicks to second. Might just be me not being used to it.

    Also gunna need a new front tire for her. Can anyone recommend something? Looking for something that can be used on the road and off road.
     
  9. racerx

    racerx Administrator
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    These transmissions need some forward motion to shift consistently. Try shifting into neutral just before coming to a complete stop...or...rolling the bike forward a tiny bit; that should help. The clutch & cable also need to be properly adjusted. If the clutch doesn't quite fully release, the minuscule amount of torque will be just enough to mess with shifting.

    BTW, reading through the previous posts, I'll add some further info on motor oil choices for this machine. Back when it was new, straight 30W automotive oil was fine. These days, straight 30W is hard to find and automotive oil is radically different from what these motors need. If you want know & safe, Honda GN4 is it, if a tad on the pricey side. Valvoline or Castrol motorcycle oil...i.e. wet clutch compatible and marked "JASO spec"...are also good, same with some Yamalube, etc. Choose viscosity by operating conditions. Above 70F, 20W50 is as close as you're likely to find to the old straight 30. Below 60F, 10W40. The big change in motor oils is that bike oil still has high zinc levels (needed to protect the shift forks & gears), while automotive oils not only lack zinc, their friction modifiers will contaminate the clutch discs, resulting in slippage.

    No idea on the "best" tires for this bike. However, I'd replace both of them. 45 year old rubber is going to be crunchy, meaning rapid wear, reduced traction and high potential for failure.
     

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