Battery Required?

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Planepal

New Member
So I just acquired a basket case CT70. I think it’s a K1, it was manufactured on 12/71. I have worked on quite a few Ct 90’s and CT110’s but this is my first CT70. My question is, does it require a battery to run? I know a Ct90/110 requires one but here is what I’m experiencing. I did all the standard things. Changed the oil, cleaned out the carb and jets with a sonic cleaner, manually set the points, adjusted the valves, cleaned and set the gap on the plug, cleaned out the gas tank and installed new Fuel lines. The battery was bad so I ordered a new one. I checked for spark and sure enough, when I cranked it over, I got a spark. So I squirted a little starting fluid in it and fired up for about 2 seconds and died. I tried it a few more times and it would run for a few seconds and die. I didn’t want to use too much starting fluid so I stopped. I pulled the float bowl and it had fuel about 1/2 inch below the top of the bowl so it seems to be getting fuel.
So my question is, will it run without a battery? My new battery will arrive in a few days. I didn’t have the old battery installed so if there isn’t a battery installed at all should it continue to run?
Thanks.
Paul
 
Rapidreggy

Rapidreggy

New Member
Planepal said:
So I just acquired a basket case CT70. I think it’s a K1, it was manufactured on 12/71. I have worked on quite a few Ct 90’s and CT110’s but this is my first CT70. My question is, does it require a battery to run? I know a Ct90/110 requires one but here is what I’m experiencing. I did all the standard things. Changed the oil, cleaned out the carb and jets with a sonic cleaner, manually set the points, adjusted the valves, cleaned and set the gap on the plug, cleaned out the gas tank and installed new Fuel lines. The battery was bad so I ordered a new one. I checked for spark and sure enough, when I cranked it over, I got a spark. So I squirted a little starting fluid in it and fired up for about 2 seconds and died. I tried it a few more times and it would run for a few seconds and die. I didn’t want to use too much starting fluid so I stopped. I pulled the float bowl and it had fuel about 1/2 inch below the top of the bowl so it seems to be getting fuel.
So my question is, will it run without a battery? My new battery will arrive in a few days. I didn’t have the old battery installed so if there isn’t a battery installed at all should it continue to run?
Thanks.
Paul
Click to expand...
Yes it will run but you will not have lights or horny I run mine with no battery
 
P

Planepal

New Member
Glad you corrected that! I sure don’t want to not be Horny because my bike doesn’t have a battery, LOL. If it’s supposed to run without a battery then I have a problem. The compression could be low, I’ll check it tomorrow. If the compression is ok, then the carb must not be supplying fuel. Maybe the jet got clogged with some random crud. I’ll check the main jet if the compression is good.
 
Gary

Gary

Well-Known Member
You don't technically need a battery but you do need to jumper the black wires on the harness at the battery plug. You can either just cut off the plug from the battery and use it or make a jumper or leave the dead battery in place and plugged in.
honda ct70 jumper wire.jpg
 
P

Planepal

New Member
So if they’re not jumpered, it would fire and run for a second or two then die? I’ll definitely jumper those today and try it. Thanks. These CT 70’s are definitely different than the CT 90/110’s. They hold a special spot in my heart because it was the first bike I ever drove. A 1970 Candy Apple Red CT70 that was my older brother’s. I’ve been riding my whole life but that bike was so cool back then. It seemed so big and fast then and now it’s tiny and underpowered but it’s still cool. Thanks again.
 
OLD CT

OLD CT

Well-Known Member
A fresh battery keeps the bulbs healthy. If you don't care about the bulbs, you are good without it.
 
kirrbby

kirrbby

Well-Known Member
CT70s can definitely run without a battery...but it's not recommended because you WILL blow the bulbs if you run/rev it with no battery to buffer voltage. Unplug your bulbs tho and you can run it all you want.
 
P

Planepal

New Member
Good to know, thanks. I finally got it running yesterday. I pulled the main jet again and the main orifice was clogged. I had run it thru the sonic cleaner but forgot to run my guitar string thru all the holes. It fired right up but smoked quite a bit at first but has almost stopped smoking now. It has leaked oil thru various seals so I’m going to check the crankcase vent today. The bike keeps running after I shut the key off so I have to pull the ground jumper wire to shut it off. I know on the Trail 90, you can burn the points if you leave the ignition on but since the points only get power when you kick start the motor, will it hurt anything if I leave the jumper connected?
My new battery should arrive tomorrow so I’ll have to check the bulbs and see if they are blown. I have a shopping list and I went on DrATV’s website but it looks like they only sell off of Ebay now. That has always been my go to for hard to find CT 90/110 items. Thanks for all the advice.
 
P

Planepal

New Member
I‘ll check it out. I think the switch is going out or there is a bad connection because the switch started cutting off the motor when I switched it off but then it quit running at all. No spark at all with the key on and the jumper connected. I rotated the switch several times and ot started firing. I have a spare switch from a CT90 that I think is compatible. How long is the pigtail on the stock switch? Does it go down under the fuel tank or is it about 6-8 inches long? I would think you would have to pull the fuel tank to access it?
thanks.
 
OLD CT

OLD CT

Well-Known Member
Trying a different key switch is a bad idea. I have heard it a good way to fry the harness. Not worth risking. This is for a K0 CT70. Not a K1. The green wire is 6 inches?

IMG_1841.jpg
 
P

Planepal

New Member
OLD CT said:
Sounds like the green ground wire is unplugged on the key switch inside the frame.
Click to expand...
Guess what? The green wire was disconnected! I used a mirror and it was completely separated. I pulled the tank and pulled the wiring harness out of the top tube and headlight bucket, bench checked the switch and it was good. After cleaning all the contacts, I wrapped the round connector and the green bullet connector with electrical tape to make sure it doesn’t separate again. The switch turns the bike off properly now. Thanks for the tip.
 
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