New to me UJM

[LongRanger_imp]

Cormanus, yep, it’s a reversible 1/2” drive handheld driver that you whack with a hammer and twist at the same time. I doubt they’ve changed much over the years. Quite crude, but effective nonetheless.

[Bazbro_imp]

Be careful using it on alloy/cast components for fear of cracking/ shattering them.

[PowerDubs_imp]

I've used them on countless old dirtbikes in my youth- quite aggressively- never an issue, regardless of aluminum, magnesium, plastic.

[LongRanger_imp]

Ride #2 didn’t go so well. About two miles into the ride today, the bike began to lose power and bog down. It finally died on the side of the road and wouldn’t restart. I waited about five minutes and it started, albeit sluggishly. Another 1/2 mile down the road, it died again. Engine would turn over but not start. I waited about thirty minutes, got it to light, and turned around and nursed it home. It died again on the way but I was on a downhill and was able to roll into the garage.

I don’t think it’s fueling — I think it’s ignition-related. As a nearly 50-year old bike, I think something is generating excessive resistance as it heats up. I’ll go through all the connections again and start with the coils and plug wires.

[max]

LR have a look at the vent hole in the carbs, there should be a very small orifice which vents to the outside air.
if it is blocked the air warms up and lowers the fuel level in the float chamber and........
it usually has a bit of fuel deposits around it and over time it gums up, just a thought.

[suhawk305]

Ride #2 didn’t go so well. About two miles into the ride today, the bike began to lose power and bog down. It finally died on the side of the road and wouldn’t restart. I waited about five minutes and it started, albeit sluggishly. Another 1/2 mile down the road, it died again. Engine would turn over but not start. I waited about thirty minutes, got it to light, and turned around and nursed it home. It died again on the way but I was on a downhill and was able to roll into the garage.

I don’t think it’s fueling — I think it’s ignition-related. As a nearly 50-year old bike, I think something is generating excessive resistance as it heats up. I’ll go through all the connections again and start with the coils and plug wires.

My first thing I would check is your condenser(s). I recently had a problem with my CB77 where after it was running for a while, one of my cylinders was back firing upon deceleration, and the bike would stall. I replaced both condensers and reset the points and the bike ran perfectly. I’ve had condensers failures in the past with various synonyms.
Anotherthing I’ve read is a battery dropping below 12.5V could affect your engine. Although, I can’t confirm that.
I belong to a forum “Vintage Honda Twins” which has a lot of knowledgeable members on restoring and maintaining our Honda Twins. If you join, you can mention my suhawk305 handle to speed up your approval.
https://www.vintagehondatwins.com/forums/forum.php

[LongRanger_imp]

Thanks guys, much appreciated. I’ll chase both of those down. And suhawk, thanks for the referral. My account should be activated shortly.

[GoldOxide_imp]

Ride #2 didn’t go so well. About two miles into the ride today, the bike began to lose power and bog down. It finally died on the side of the road and wouldn’t restart. I waited about five minutes and it started, albeit sluggishly. Another 1/2 mile down the road, it died again. Engine would turn over but not start. I waited about thirty minutes, got it to light, and turned around and nursed it home. It died again on the way but I was on a downhill and was able to roll into the garage.

I don’t think it’s fueling — I think it’s ignition-related. As a nearly 50-year old bike, I think something is generating excessive resistance as it heats up. I’ll go through all the connections again and start with the coils and plug wires.

My first thing I would check is your condenser(s). I recently had a problem with my CB77 where after it was running for a while, one of my cylinders was back firing upon deceleration, and the bike would stall. I replaced both condensers and reset the points and the bike ran perfectly. I’ve had condensers failures in the past with various synonyms.
Anotherthing I’ve read is a battery dropping below 12.5V could affect your engine. Although, I can’t confirm that.
I belong to a forum “Vintage Honda Twins” which has a lot of knowledgeable members on restoring and maintaining our Honda Twins. If you join, you can mention my suhawk305 handle to speed up your approval.
https://www.vintagehondatwins.com/forums/forum.php

(+1) on the battery suggestion sukawk305.

[max]

The condensers are certainly worth a look but it is not likely that they both fail at the same time and then work again, just an idea.
Their job is to extend ignition points life by absorbing the spark between the points and the bike can run without them just to prove the point for a short period.

The fuel filter is easy to check, just pull the hose off and open the tap, should flow fine.
Have you checked the fuel bowls ? ( release the bottom drain screw on the float bowl and check for water etc. ),
can also check the fuel delivery that way so the filter, hose, float needle and any thing else is checked as the flow should be sufficient, it's a quick and easy check to do and the reason Honda puts them in for our convenience.

My cb550 drops 1,5 volts between the battery and the 12v side of the coils, always has done, so that's not perfect but normal given the path of the 12 volt supply through the harness, switches, fuses etc. at 5 Amps or so.

[LongRanger_imp]

Both condensers check out fine on my multimeter but I’m replacing them anyway. I’ve reset the points gap and ignition timing (it was a bit retarded) but the left plug isn’t firing. I think the cap is suspect so I’m replacing both of them. Both the primary and secondary coil leads are showing the correct resistance but neither of the secondaries show a spark when I test them independently. Hoping it’s just an anomaly and the new caps resolve the issue. If not, replacement coils are inexpensive.

I’m enjoying tinkering with this bike. It’s a fun project and I’m relearning a lot of stuff I used to know many moons ago. The OE-spec NGK spark plugs were discontinued several years ago but I’ve successfully tracked down a few leftovers. Everything else seems to be widely available and quite inexpensive. So far, so good