Honda Idle Speed

How do I adjust idle speed on 1965 C100 Cub . it’s idleing too slow

Thanks

Re: Honda Idle Speed

Probably the idle adjustment screw.

Re: Honda Idle Speed

Do you have a service manual ?

https://free-downloads.online/7711-0-c5e0c2f6/signup-blitz/#/c_bg={c_bg_enc}/z=53077/dp=1800265051.538570.89c7d42b35.35062.5f75bfe46e8a6a9b643b1634d589ade6/q=Honda+c100+service+manual/

Re: Honda Idle Speed

probably best to adjust airmix and idle.

idle's easy, there's one longer copper lookin screw sticking out on the side of the carb, you can usually get it by hand without tools. turning that in raises idle. that easy.

there's a second screw that adjusts the idle air mixture, it'll be right next to the idle screw, but flushed in a little recess, needs a flathead. to start, turn that all the way in then back it out 2 full turns. Then start the bike and get it idling, then adjust that mix screw in or out to adjust the air mix - when the air mix is good, it will idle higher so turn the screw whichever way makes the idle go up until you find a maximum, that's proper air mix setting. next use the idle adjust screw to bring the idle back down to a steady good rpm. now you've got idle and idle airmix set! perfectamundo

Re: Honda Idle Speed

I got the bike running yesterday ,took the carb apart and cleaned all the parts , took pleanty of pictures. It was leaking where the cock cap and levers located. It’s still leaking but not near as bad. I’m not sure what to try next ,there’s really not much to it. I checked compression with Harbor Freight type gauge, it was 50#. The motor however really sounds strong. Thanks again for all your tips ,I’ll adjust the idle as you suggested.Thanks

Re: Honda Idle Speed

When checking compression : throttle should be wide open and the cylinder should not be dry ( lightly lubed by either a mist of spray oil or fuel mix or ... ) .

And , be sure the exhaust is clear .

Re: Honda Idle Speed

I just checked comp again after running for 10 minutes, it was still 50 ,then I sprayed

some foggier , checked it and still the same had throttle wide open , it may be the tester, I’ll check the exhaust it sure sounds like a beast, runs smooth and no backfiring. It’s a little cold out for a test drive and I really don’t know how to operate it yet. My Grandsons are coming over tomorrow, they can be the Guenia pigs.

Thanks again

Re: Honda Idle Speed

You could check the 'tester' on another , known good , motor .

Re: Honda Idle Speed

car testers dont work very well on small moped cylinders either.

if it's leaking you might be able to adjust the float. most of the cub floats, you could slide the needle up and down in the float. sliding the float down makes it shut off sooner and push up more firmly. beyond that any leaks could be from grime or dirt still in there on the sealing surface, or actual damage. might be possible to clean, or lap it just by twisting the needle in the seat. if it doesnt improve trying it dry, could take a whack using lapping compound or even toothpaste, and of course clean it out real well after.

Re: Honda Idle Speed

That’s more great ideas I’ll try moving the float a very little and work the needle more

It’s hard to find just the few parts you need ,not like the Sachs where about any part is available. If this doesn’t work what do you think about just buying a new carb ? They have what they claim is a original for $80 including shipping. It just needs a small mod of the hole spacing 1.5 mm I’ll probably keep this bike and hand it down to my Grandkids. Thanks

Re: Honda Idle Speed

Yea it’s probably just a bad float needle.

Check the float by flipping the carb over & blowing into the gas inlet.

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