Weird issue suddenly, thinking it's the carbs

[Splexin]

Suddenly my motorcycle has been running like **** below 3K RPM, I am thinking it is the carbs but want to know what you guys think before tearing it down.

Seems to be charging fine (will test volts when I get time), although when I turn on the blinker and hold the thottle open, the engine revs in sequence to the blinker. So if not carbs possibly issue with charging or timing (i.e. TCI going out....?).

Right cylinder spark plug is fine, maybe a pinch lean; left cylinder spark plug has a bit of carbon but not an amount to warrant carbon reading from spark plug chart.

I've ran Seafoam through in the fuel but no improvement. Didn't really start acting up until I fueled up at a hole-in-the-wall gas station (was in a hurry) and set off on the same 40 mile ride that stranded me last time

Accelerates fine above 3K RPM but if I let it go back to idle (i.e. traffic light) I have to sit on the throttle and rev it until it "clears up" and let's me go again, otherwise it just bogs down very badly. This is why I think it's a carb issue.

Using the blinker causes a loss in power, which may point to a charging issue. But as you guys know I resolved previous problem. Unless my original VR just went out, very doubtful.

I have a timing light, even though this is TCI should I check rotor timing (i.e. maybe I moved it out of timing when I replaced)? My bike is an 80G.

The bike is driveable but it's very annoying and I know it's not good to leave issues unresolved. Thanks.

 

[Royboy]

If the engine revs in sinc with your blinker I'd say you're running on very marginal voltage.

 

[Downeaster]

Running like crap at lower RPM indicates a voltage problem too. At high RPM the alternator is making enough voltage to run the bike. At lower RPM, alternator output drops and if the battery isn't up to snuff, the ignition suffers.

First check is battery condition (voltage, water/electrolyte level, clean tight terminal connections, good ground, load test) and then charging system (output at 2500+ RPM, brushes, check to see if magnetic field is there when key is turned on).

 

[Splexin]

That's what I'm afraid of. I've had so many electrical issues with this bike that every single electrical part, even the wiring and stator, has been replaced bar the regulator. Strangely, 2 brand new regulators from Mikes didn't work but my original did.

Passes key-on slap (wrench) test. I'm using AGM battery, installed May (I think) this year.

Next I'll be testing voltage, now that I think about it-- a few weeks ago I had a minor lost-power/blinker-on issue and thought it was my charging system *again*....checked voltage and everything was fine. So I'll have to see if that's the case this time.

 

[5twins]

Well yes, it could be the carbs. Your pilot circuit may have gotten plugged. It happens, even to the best of us. If all that electrical stuff checks out, clean the pilot circuit (although I'd do that 1st).

 

[gggGary]

jumper to a bigger 12 volt battery how does it idle and run when you turn the blinkers on? Load test that AGM for sure.

There have a been a lot of premature failures of AGM batteries. I got a bad one myself on a Honda 1100 took me a while to realize a recent new part was the issue.

 

[rebel542]

It's electrical. Follow Gary's lead.

 

[Splexin]

Tested voltage.......

12.70 off (overnight)
12.36-40 idle
14.20 @ 2500K+ RPM

Blinker on:
No wavering @ idle, voltage high 12.20s.
Wavering in sync with throttle open, voltage still in 14s though.

Clarification: the engine revs up as the blinker goes off and loses power as the blinker flashes on.

The system is charging, yet power loss in sync with blinker???

Also noted that bike isn't running crap at idle like it was after long ride yesterday.

 

[weekendrider]

Do you have the tail wagging the dog?
Could it be the light is wavering with the motor? Not the motor wavering with the light?
just asking cause I don't know.
As for crappy low end put me in the clean your pj camp.

 

[Dennis]

I had a similar problem last year
Went threw everything I could find
Ended up that I needed a stronger magnet on the rotor for the pick up
Not sure if you have TCI or not
but if you do its an easy thing to eliminate

I first noticed mine when the turn signals where on
then noticed the same problem with the break on and the the high beam

 

[Splexin]

Yes, I do have TCI. The rotor is new though. So, most likely the pickup would be the issue?

 

[Dennis]

I only had my rotor a year that was rebuilt from custom rewind

 

[littlebill31]

Don't forget to check your brushes.

 

[Splexin]

I've had my rotor 2 months and it is factory oem.

littlebill, if my charging system is working does that mean my brushes are fine? They appear to be set correctly, they aren't digging into my rotor or anything. I mean, they should be OK since they are new also.

If I was to put the blame on a specific element I would say something with TCI or carbs or maybe rotor timing (if that affects TCI at all).....everything else was combed over during the last issue (charging). And according to my tests the charge is being delivered to the battery so there is no logical reason why the motor is losing power with blinker on......the load isn't affecting the charge enough to cause it to do that under normal circumstances......even when I had charging issues I never experienced the wavering effect.

 

[gggGary]

"
12.70 off (overnight)
12.36-40 idle"

I don't think that is a good (or at least not great) 1200 RPM idle voltage, what RPM are you idling at? I think the last barn find TCI bike I tested was idling at 13+ volts. Did you do a battery load test or try a larger battery to see if that made a difference?

 

[Splexin]

I don't remember the idle RPM from the test, it may have been 1K definitely less than 1.5K, although with the issues I've been having lately sometimes I've had to turn up idle mixture to keep the engine from stalling (one point for possible carb issue). I will test again tomorrow.

Isn't a load test for CCA? The bike starts on the first try. Can this be done with my VOM?

I don't have any other batteries except the old acid, which was replaced due to lack of holding charge. I suppose I could charge it up and compare but not sure it would be fare any better than this one. Btw, my AGM is the one from MikesXS, just for reference.

I wonder though, even if the battery is the problem why would I be losing power when the charging system is charging the battery? I can see losing power with low voltage but the readings are in the 14s. I'm not losing power at idle, even with blinker on the engine runs fine. Only when I open the throttle in the low range does it waver, past 3K RPM and problem disappears. The throttle lags and seems to hang while in low range, I sprayed carbs boots but no air leaks. Maybe I will upload video to demonstrate

 

[gggGary]

I was thinking jumper to a NOT RUNNING car truck garden tractor something like that. A battery can seem fine and then under a load like say a headlight for 5 or 10 minutes show you that it's not so healthy. As always bad connections, ground problems need to be eliminated as a possibility.

 

[Splexin]

lol oh okay well I don't have any other vehicles.....this is my only transport and don't know anybody to loan one.

That makes sense....and it would explain why I can drive around the city even on highway for a bit (15 minute or less trips) for weeks on end, but then when I take a long trip I start losing power cause battery can't hold load? Maybe? Does that make sense? I did run bike with blinker on for a few minutes and voltage didn't go down from initial load.

When Dennis mentioned he had same issue, I went out and ran it and pressed brake light and ran crappy just like he said had happen.

 

[Dennis]

sorry dbl post

 

[Dennis]

where did you get your rotor from?
I am sure you have read many posts as I have about them
from my peronal experiance and I am no expert
I would try the trigger magnet
extremely cheap and easy to do
I would hate to see you rip apart your whole harness as I did for something so simple