[Lunatuck]

Struggling with an issue where the bike starts easily, rides fine for about 2-3 minutes. Then its idle drops and it wants to stall. At this point, it wont rev out. Hangs at about 2k.

I’ve done everything I can think of…
-Checked timing (points, valves, etc…)
-Replaced carb boots
-rebuilt top end with new rings
-put on oem air filters
-checked gas supply
-reset floats

I’m starting to wonder if it is battery related because the battery will frequently lose charge and need to be charged after one of these test runs.
Regulator seems to put out 13.2v when running.
I’m lost here. Any tips?

 

[mike in idaho]

Did you verify, with a timing light, that the spark advancer is working properly?

 

[Lunatuck]

Did you verify, with a timing light, that the spark advancer is working properly?

I haven’t yet, but will pick up a timing light as soon as I can.

 

[Day444rider]

Regulator seems to put out 13.2v when running.
Voltage seems a bit low to me. I'm thinking it should be in the 14.8 range.

 

[circling the drain]

but if it's 14.8 he'd likely have a lithium ion fire or explosion under his seat, those batteries don't like voltage above 14.5

 

[theblooms]

If you're running Lithium, I highly recommend a modern MOSFET regulator/rectifier vs using the 40+ year old stock one.

 

[Lunatuck]

I am using a new reg/rec, but it was a cheap ebay one. Wondering if that’s the cause of my problems.

 

[Augshire]

You need a regulator designed to be compatible with lithium ion batteries. The best are made by Rick's Motorsports, and they are not cheap. I've added a link to a trusted website called cognitomoto for your bike

Custom: Ricks Regulator / Rectifier for Lithium Ion Batteries CB350, CL350, CB360, CL360, CB450K , CB500T

The 14-135H will not mount in the stock location; installation instructions will be included with your order. OEM Style Honda Rectifier-Regulator for Lithium ION Battery Systems: Rick's part #14-135H works with the stock stator to provide an upgraded charging system - it allows the stator to...

cognitomoto.com

 

[Lunatuck]

I may just switch back to my old battery to see what happens.

 

[theblooms]

cheap ebay one.

Yup. Found your problem right there.

As was mentioned, Rick's makes a good regulator, and personally I run one sourced from Sparck Moto. Also good people.

 

[Lunatuck]

Got a timing light. Timing is slightly off at idle, but needed to warm up the bike to do an accurate test. So I replaced the battery and went for a ride and had no issues. I hope the issue was the battery! Been struggling big time.

 

[Lunatuck]

Had a nice ride, but it’s got a hanging idle. I can’t find any air leaks, but am starting to wonder if timing chain could be off a tooth. The advance unit looks ok, but not sure. It doesn’t have any rough spots if I rotate it.

 

[Montanabill]

If your cam chain was off you would have a hard time setting the timing and it would generally run poorly.
You probably have old carb itis. set the idle low when it warms up and then see if the idle mixture screws effect the idle and the hang idle.

 

[Lunatuck]

Got about a 5 mile ride in, everything went perfectly, then when pulling up my driveway; it lost power and wouldn't rev above 2000rpm. I gave it some time to cool down, then it was running fine.

 

[jayel2]

Gas cap not venting? Try removing gas cap when it's not running right to see if that corrects it.

 

[Lunatuck]

I’ve tried the gas cap. It really feels like a fuel starvation issue, but could be some sort of electrical issue. I am blowing light bulbs.
Have a new regulator coming. Will see if that helps.

 

[Montanabill]

Next time you ride it hook up one of those less than $10 volt ohm meters and leave it hooked up while you ride it. Helps to troubleshoot electrical problems. Those bikes came originally with a separate regulator and rectifier. Do you still have the original high/low/off headlight switch since that switch turned on an extra winding in the alternator when the lights were on.

 

[Lunatuck]

Next time you ride it hook up one of those less than $10 volt ohm meters and leave it hooked up while you ride it. Helps to troubleshoot electrical problems. Those bikes came originally with a separate regulator and rectifier. Do you still have the original high/low/off headlight switch since that switch turned on an extra winding in the alternator when the lights were on.

Yes. Original switch. I’m thinking of splicing the yellow and white wire. Not sure if that’ll help with voltage.
I have a multimeter. I could try riding with that.

 

[theblooms]

Yes. Original switch. I’m thinking of splicing the yellow and white wire. Not sure if that’ll help with voltage.
I have a multimeter. I could try riding with that.

It allows the stator to put out full voltage whether or not the headlight is on. I did that to my bike, it was pretty easy.

How I did mine was, I depinned the stator from the harness connector. I then used some automatic wire strippers to expose some wire on both the yellow and white wires about 3-ish inches from the connector. I twisted them around one another, hit it with a dot of solder to make a good connection, then sealed everything up with some marine grade heat shrink. Then I simply put the terminals back into the connector and plugged it back in. All told, it only took about 5 minutes!