Topic: Bogging, misfiring and running like trash (SOLVED!!)

[scottly]

Per, did your intermittent coil lead cause the spark plug to turn black? No spark means no fire, and it takes fire to make the carbon that turns a plug black. "Behaved like a carb problem" is not the same as reading the spark plugs.

[spmc]

Per, did your intermittent coil lead cause the spark plug to turn black? No spark means no fire, and it takes fire to make the carbon that turns a plug black. "Behaved like a carb problem" is not the same as reading the spark plugs.

Thanks Scottly, I'll be pulling the carbs again anyway because last time I did the rubber boot on the carb diaphragm rod was so brittle and hard it basically turned to dust when I pulled off the bowl. So if you do think it's a carb issue do you have any tips for what to look out for? I may not have cleaned them as thoroughly as I thought having just done some further reading. So I will give that another shot.

[BobR]

Have you checked fuel delivery? Clogged screen in fuel valve or kinked hose? Bob

All four bowls were full of gas when I pulled the carbs so I don't think that was the issue, and I can run it idle with the choke fully open although it's not purring like it did.

  I was thinking that with a partial restriction it would still fill the bowls but couldn't keep up with demand under load- just a thought. Bob

[PeWe]

Per, did your intermittent coil lead cause the spark plug to turn black? No spark means no fire, and it takes fire to make the carbon that turns a plug black. "Behaved like a carb problem" is not the same as reading the spark plugs.

Thanks Scottly, I'll be pulling the carbs again anyway because last time I did the rubber boot on the carb diaphragm rod was so brittle and hard it basically turned to dust when I pulled off the bowl. So if you do think it's a carb issue do you have any tips for what to look out for? I may not have cleaned them as thoroughly as I thought having just done some further reading. So I will give that another shot.

It fulfilled this: Bogging, misfiring and running like trash

[scottly]

Any number of things could fulfill those symptoms, but a black spark plug indicates a carb problem.

[spmc]

Okay pulled the carbs again after I was convinced I probably didn't do as thorough job as I initially thought.

Float pins all in good shape
Main and Slows clean as a whistle
Pilot Needles all in good shape
New accel pump diaphragm, spring, and boot thingy

It definitely idled stronger, didn't need the choke on for it to run normally, but still bogged down off the line in gear 1 and 2, but seemed to be better in 3 (in the city so didn't really have the runway to open it up further.

Doing some more reading on some great posts by Flybox1 and see I didn't fully check the accel pump holes and I couldn't really figure out how to clean the tiny holes in the nozzles that squirt fuel into the carb throats. Will remove the connector hoses between the carbs and shoot carb cleaner into the male brass reducers as per other threads.

Any other suggestions on where I should be looking for obstructions based on my symptoms?

[Biebs]

Have you change out the gas that was in the tank when this started???

Sound like you have some bad gas!!!

[spmc]

Pulled the carbs yet again... Cleaned every nook and cranny, thought i may have it when it felt like I cleared a blockage from that tiny brass hole with the o ring from the accel pump feed but still when I fired it up it idled fairly well but still with the lack of power when throttling quick.

It seems to have changed bit now though. Yesterday after I worked on it when I rode it to test it it felt like little surges of power, like it was dying then got back up, then died again. Now it felt like fairly low power, no get and go, but consistent, and lots of backfires in the gears, in third it seemed to run fairly decent.

Any ideas? Cause I'm all out, feel like I'm throwing a dart blindfolded.

[dave500]

itll be impossible to clean carbs thoroughly with out an air compressor.

[BobR]

Perhaps one of these days you’ll measure the fuel height with the Clear Tube method and confirm what’s going on with the fuel supply to the carbs...

 This ^ -and confirm adequate flow rate to the carbs too might be useful. Bob

[spmc]

itll be impossible to clean carbs thoroughly with out an air compressor.

I've been using canned air in lieu of... will do the clear tube test next.

[scottly]

Pulled the carbs yet again... Cleaned every nook and cranny

Did you remove and clean the emulsion tubes? That's where fuel from the main jet first gets mixed with air.

[my name is nobody]

Perhaps one of these days you’ll measure the fuel height with the Clear Tube method and confirm what’s going on with the fuel supply to the carbs...

 This ^ -and confirm adequate flow rate to the carbs too might be useful. Bob

A carb may be loading up as you are driving. Not sure if the F model has a manual petcock
or vacuum operated. Have you tried turning the fuel off during the malfunction to see if that makes a difference? Does gas ever come out of the overflow tubes? I don't have the same carbs as yours, but I just this past week had this EXACT symptom with my bike. It drove me nuts
chasing it. My #4 carb would load up intermittently, (moreso when I was RIDING than when the bike was parked) It finally told on it self when the float stuck open and stayed that way. Can't say
for sure if that is your problem, but the way it acted was the same as you're describing.
A clear tube check would be a good idea. Just my .02...

[spmc]

So I've gotten the chance to do the clear tube check. I also had to make sure the little vents to atmosphere were clear before I could get an accurate reading... Got all the floats set so that the fuel level is at the generally agreed upon 3-5mm under the seam. I've cleaned every hole and passage I'm 99% sure. Now it seems to just be popping and backfiring quite frequently. No real get up and go to speak of and seems to want to die even at idle until it gets really warmed up. Screws are set to two turns out, I understand 13/4 was factory for the PD41B carbs?

I checked my points gap and adjusted them so they start to open just a hair in front of the Fire mark. I'm still seeing sparking on the 2-3 side so I'll order a new set (or should I just take the opportunity to switch to magnetic?)

So I kinda feel I need to start at the beginning again... What could happen rather suddenly, on a drive home at no more than 50km'h, that could cause the bike to go from running like a champ, to chump?

[PeWe]

Ignition

[Kevin D]

So I kinda feel I need to start at the beginning again... What could happen rather suddenly, on a drive home at no more than 50km'h, that could cause the bike to go from running like a champ, to chump?

spmc, mine went from chump to champ when I changed the sparking 2-3 condenser.

There were some other parts involved (bad plug caps and bad float) but the condenser was the villain in my episode.

http://forums.sohc4.net/index.php/topic,161232.msg1856614.html#msg1856614

[piefairy]

I'm new and don't know much, but sounds like my bike. It would backfire, and have little to no high end. It wouldn't even get over 6k rpm... until I pulled the pods. Have you checked your air filter? You could have sucked up something nasty on your drive and caused some issues. Thats just my 0.0000002 cent...

[spmc]

SONOFABEEEEACH. I'm fairly certain the culprit was the points! Specifically the 2-3 Contacts. They were arcing and I think not allowing the sparks to fire as they should. I suspect that to be the reason it runs (ran?) bad in the rain as well as water would get in and exacerbate the situation. Because I've read it's a worthwhile upgrade I bought a Dyna S ignition.

Installation was fairly straightforward though I will post this here in case someone else stumbles across this thread with the same issue. I was trying to do the static timing with the light but couldn't get the light to actually come on at all. I thought it was the black/wire as I wasn't getting any power reading on that either. I even followed the line into the bucket to see why this power wasn't getting to where it should. I then realize the ignition switch is set in the off position. Ugh. Turned it on and it was timed and fired up with more torque and get up and go then it has ever had. No backfiring or popping whatsoever. FINALLY!

Thanks to all who offered help and best guesses with the situation!

[dave500]

I love electronic ignitions,they really make these bikes run with that edge better,sure points are good when all new etc but as time wears on theres too many moving parts just to switch coils on and off,well done,a lot of people have trouble setting points up correctly and a lot of people lack the patience to do it properly as well as lacking the tools,you gotta have a strobe and dwell meter full stop,the gap setting is ball park as far as im concerned a bit like bench syncing carbs,itll get you running ok but finer tuning and the motor gives its all.

[PeWe]

Everything can fail if not properly set/serviced or adjusted.
My bike has never run bad like that due to the ignition. Points used over 100.000km. But I have replaced the point plates/condensers as a service job when I did not have the experience as I have now.

Except one holiday on my way home. Bad connection of one of the wires feeding the coils.
I had a point that broke once (daichii) solved at a nearby shop.
Later longer problems was a broken new Dyna HT lead. Plus a short lived Pamco.

Ignition with its important 12V, grounding can cause issues important to fix before attacking the carbs No ignition system is safe then

[HondaMan]

Everything can fail if not properly set/serviced or adjusted.
My bike has never run bad like that due to the ignition. Points used over 100.000km. But I have replaced the point plates/condensers as a service job when I did not have the experience as I have now.

Except one holiday on my way home. Bad connection of one of the wires feeding the coils.
I had a point that broke once (daichii) solved at a nearby shop.
Later longer problems was a broken new Dyna HT lead. Plus a short lived Pamco.

Ignition with its important 12V, grounding can cause issues important to fix before attacking the carbs No ignition system is safe then

Not to mention that in this year alone (since January) I have "fixed" by e-mail or in person, 4 of the SOHC4 bikes that had a bad (brand new) condensor, from (yep...) Daiichi...