A little video to accompany my descriptions. Watch the whole thing. Idle degrades as time goes on. Turning the choke on made it worse. It took a lot longer for the bike to warm up and the symptoms to show today. Usually dies down much faster. We went from 70 degree weather to 35 degree weather, so that's not unexpected. Temporarily converted my petcock to a straight-through system, no restrictions. Doesn't seem to have helped any.
A little video to accompany my descriptions Watch the whole thing Idle...
Have you tried speaking/contacting Randy at RPM, what he doesn't know about FJ carbs/tuning etc isn't worth knowing and he's very helpful. http://www.rpmracingca.com
I can't quite tell if it's the same that I had on my '85, but many of the symptoms are similar. In my case I heard a distinct cough or miss. However the dwindling down to stall is very similar. In my case it turned out to be a bad coil. I believe it was the heat of the motor sitting at idle that showed the bad symptoms. It did not dwindle while I was riding, only when I stopped. It's a simple test with an inductive timing light pointed at the rotor. In any case it would mostly rule out spark. Good luck.
Definitely different. Plus, I just replaced the coils.
Did you say somewhere that you only have to pull the choke part way for a cold start?
What about your valve clearances they lesson as engine warms check that first? Cold and warm compression test!! If not that definitely fuel rich!! Ignition problems get worse as you increase duty cycle at higher revs do wouldn't affect trickier buddy!! Hope you get sorted Steve
Affect tick over
We just did a valve job 1000 miles ago. That's definitely not the ticket at least.
Sam you shure you have enough gas in the tank to reach the pickup point on the petcock. Did you remove the petcock and see if the filter screen is clogged up?
Yep. Also ran it with pouring gas down a funnel straight into the carbs. Had the petcock out twice and completely apart. Definitely not clogged.
Depends. I have noticed that it does seem to be cold starting far easier since all this started. Before, I had to go through all steps on the choke before it could idle. Now, I usually can take it off or to one step from off within one minute or two.
Honestly, it seems like a choke problem, but even running it off a funnel and messing with the choke by hand has no effect. The diaphragms look fantastic in the carbs, too. (Also was a bit flabbergasted to find out that it's a CV/slide hybrid)
Idle seemed a bit low, too.
Inconclusive,was this bike warmed-up or cold ?
Normally, before this happens, idle sets in between 1000 and 1100. Occasionally briefly hovered around 1500 after coming off the freeway.
Warm, but sat for 10-20 minutes before being fired back up. It was running for another ~10 minutes before I took this video.
Engine has to be at operating temp before the issue shows symptoms.
Did you try different pickup coils?I know you have new ing. Coils.
Pickup coils ohmed out perfectly in spec.
if it starts failing when warmed up check your stator windings as they might have cracked varnish coating only noticeable when hot
That's interesting. Haven't checked that yet.
Check for air leaks,spray some cab cleaner around the carb while running,be careful !
Hot and cold?
Used the fancy hair dryer trick...
Not sure if hair dryer would get the coil hot enough? Mite try on the eng after its hot.
Damn good idea !
Battery voltage.stator issues
Already checked. Potentially very minor leak, but couldn't replicate the issue.
Battery is great. 12.45 volts with bike off on random check.
Not the stator.The battery is a buffer.Low voltage would be a problem
Sorry ignition pick up in the stator.