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HONDA CB100 FrankenBike ( No Running Lights )

4812 Views 26 Replies 5 Participants Last post by  Boostamante
So i bought this 1972 Honda CB100 a while back for a couple hundred bucks. It ran a bit rough and had no lights wired up. Since then i have ran new gas in it and have managed to get her running somewhat decent ( might need a carb clean and new gaskets ). I see no evidence of a stator and it seems to only been used as a dirt bike in its past life. I would love to run lights and have at least a working brake light but cant figure out what the best way to go about it. Cant really tell if the engine is the original CB from another bike or a CL. ( the original exhaust ran High vs the low CB style ).

I have 2 options in my head, one is run a LED head light and wire up a small 12v battery or figure out they correct stator that will work with mentioned engine ( The isnt option isnt ideal but it works ). Currently the bike runs without a battery and has one wire coming out the left side that goes to a kill switch.

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xr motor the engine numbers will tell you
total waste of money to try to make it road leagal
Its considered a CB though as thats what the paperwork and the Serial says. Would that not be a reason to try and run it with lights? I get that it was a "dirtbike" motor, but could install a stator or perhaps and battery-less option is out there?
The engine is a '78-later XR100 or XL100, which is not closely related to either the CB100 or CL100 engines made in 1972. The engine is actually a bored out version of what was originally sold as the XL75.

View attachment 76665

The lack of lights and battery suggest it's the XR version. 80cc and 100cc versions were made for many years and lasted until 2013 as the CRF100.

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This explains why the CB100 Exhaust didnt quite bolt up. HA! Hence the funky mod exhaust i did. If its a XR100 engine, how can i tell? engine is stamped with HE01 and cant seem to come up with anything using google
i already told you, the engine capacity, it is stamped into the fucking cylinder fucking barrel
it is actually fucking cast right in to the fucking aluminum
if you cant even follow simple things like where to see the capacity of the engine,how the fucking hell will you learn to fix your motorcycle over the interrnet ? thats the point nobody does and that is another reason not to own a fixer bike because you know nothing
read books if you want to repair a motorcycle
trying to get that machine worthy for street riding is pure insanity ,why not just flush your money, all of it ,down the toilet ?
ride it like it is until it breaks and then give it to some young 'un
My, aren't you FUCKING helpful. Eat a bag of dicks you silly, angry fuckbag.
I think he was saying how could he tell if it was a CB100 or XR100 engine, which would both say "99cc" on the barrel.
I couldn't even find that. :/ It's ok, i appreciate your help. I'm not complaining much about the bike and it's condition since it only cost me 300 bucks. I just wanted to know what what engine it was since someone pointed out to me that it might have also been a CL100 motor. Seeing how it's the 1st moto i've ever owned / bought, i really just wanted to know what I was dealing with here. The XR seems to make the most sense seeing how it's set up. If nothing else, it will make a rad little dirt bike. Just be nice to set it up with a Headlight and a Tail Light.
I believe XR80s and XR100s were HE0's

1983 starts with HE0#E-52~
1984 starts with HE0#E-53~
1985 starts with HE0#E-54~
Seems I have the 80cc engine. At least i know that for sure now. Wanted to make sure so i could order a carb rebuild kit as it idles a little rough and am afarid to crack her open and find out i need to replace gaskets. Would the XR100 /CB100 carbs / kits be the same?
seems i have the 80cc engine. At least i know that for sure now. Wanted to make sure so i could order a carb rebuild kit as it idles a little rough and am afarid to crack her open and find out i need to replace gaskets. Would the xr100 /cb100 carbs / kits be the same?
nope. Let's start with this: What's the full engine number?


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That's a 1980 XR80.

All the correct parts for this engine can be found here:
1980 XR80 A Honda Motorcycle Parts
That's both good to know and a bummer at the same time. Lol, I'll get her running smooth, ride her and possibly hack job some lights for her so I can at least be visible in the hood. Thanks for your help guys!
Anyway to trouble shoot the Bogging at WOT? I've adjusted the Air Fuel Mixture screw, put in a new spark Plug, new Oil. The only thing i can think of is that the spark plug wire needs replacement and or the points need adjustment. Thoughts?
Air fuel mix is probably your low speed setting and you need to raise the main needle jet by one slot on the cir-clip, that will enrich your fuel air mix in the 3/4 to full throttle range.
... or your floats are set too low and you're starving for fuel at wot?
I'll look into that, thanks! As far as the floats go, how do you go about setting them? Im a total noob to

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Assuming since your not asking about jetting, you are below 6K' elevation. Also stock carb, stock filter and air box or filter housing, stock pipe and muffler too. If anything is other than stock, tuning or jetting your carb is in order.
any tips on tuning the jetting?
Aw crap, not sure I can make a video of that for you but I bet there is one out there somewhere.

Challenge is to find one that is not completely boring and badly narrated by a hillbilly
LOL, Yeah, that happens :p
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