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First, I did SEARCH the forums (like a pro 
) for this issue, but only found info about checking valves. My valves are in spec as of this summer when I put the top end together. Here are my symptoms.
Warming up the bike is bizarre.
She starts right up with the choke circuit opened up, as you'd expect. Instead of idling and then climbing in RPM, however, the engine idles almost immediately at 2,500 - 3,000 RPM, as if it was warmed up already. If you kill the choke, however, she dies.
Of course, if I give any throttle, she dies (because the choke is open).
Even after running for a fair amount of time (several minutes), the idle climbs as expected, and I can keep it below 2,000 RPM by easing down the choke, but closing the choke below around 25% -- she dies. Again, blipping the throttle kills the engine, like it should with the choke open.
At this point, I would guess lean condition, etc. I continue to fiddle with the pilot jets, so that is not completely crazy.
Here is the funky bit.
Once the bike has idled a bit, I can get it to run using a mix of two methods.
First, if I dial the idle screw in a bit, she will catch and run without choke after a normal warm-up period of about 30 seconds to a minute, even though blipping the throttle kills it. Once running, though, I soon find my idle running too high at a stop, so I have to reach under and back the idle screw out. This happens a few times once I am riding around, but after 2-3 small adjustments, the idle settles into the 1,050 - 1,200 range.
Second, the other thing that works is a quick combo of kill choke and blip throttle (sometimes after turning in the idle screw a bit first). Basically, if I can catch the motor running before it dies without choke and blip the throttle, it "catches" and idles normally, at about 1,500 RPM. Later, I find the idle has climbed up a bit, and need to reset it a bit to level out.
Adding to the oddity is that once I get over this weird warm-up hurdle, the bike runs nicely. I still have a slight decel popping, but I was getting that before with a lot of rich plug readings, so I think that is a small exhaust leak. Otherwise, the engine responds well to throttle, the idle does not hang, and the bike is generally very responsive -- running better than it has since I got it. Also, once warmed up, the bike starts with no problems. So this only happens at first start up.
Having to tinker with the idle screw a bit is not that big of a deal, but the symptoms are so contradictory that it concerns me. What might I look into to root out this problem. Is it just a lean idle circuit? Forgot to do a plug chop this weekend, but I will do that anyway. Last idle chop that I did, however, came out pretty good, finally losing that richness that plagued me.
Before I get the "usual suspects," I adjusted my valves, fully cleaned and rebuilt the carbs, have jetted the bike for pods and exhaust (though I continue to fine-tune the idle circuit), pet cock works fine, electrics are tight (with coil relay and Dyna-S). After my many "Noob" threads, this is not my first rodeo
. Not to say that there won't be first rodeos for me in the future, of course. 
) for this issue, but only found info about checking valves. My valves are in spec as of this summer when I put the top end together. Here are my symptoms.Warming up the bike is bizarre.
She starts right up with the choke circuit opened up, as you'd expect. Instead of idling and then climbing in RPM, however, the engine idles almost immediately at 2,500 - 3,000 RPM, as if it was warmed up already. If you kill the choke, however, she dies.
Of course, if I give any throttle, she dies (because the choke is open).
Even after running for a fair amount of time (several minutes), the idle climbs as expected, and I can keep it below 2,000 RPM by easing down the choke, but closing the choke below around 25% -- she dies. Again, blipping the throttle kills the engine, like it should with the choke open.
At this point, I would guess lean condition, etc. I continue to fiddle with the pilot jets, so that is not completely crazy.
Here is the funky bit.
Once the bike has idled a bit, I can get it to run using a mix of two methods.
First, if I dial the idle screw in a bit, she will catch and run without choke after a normal warm-up period of about 30 seconds to a minute, even though blipping the throttle kills it. Once running, though, I soon find my idle running too high at a stop, so I have to reach under and back the idle screw out. This happens a few times once I am riding around, but after 2-3 small adjustments, the idle settles into the 1,050 - 1,200 range.
Second, the other thing that works is a quick combo of kill choke and blip throttle (sometimes after turning in the idle screw a bit first). Basically, if I can catch the motor running before it dies without choke and blip the throttle, it "catches" and idles normally, at about 1,500 RPM. Later, I find the idle has climbed up a bit, and need to reset it a bit to level out.
Adding to the oddity is that once I get over this weird warm-up hurdle, the bike runs nicely. I still have a slight decel popping, but I was getting that before with a lot of rich plug readings, so I think that is a small exhaust leak. Otherwise, the engine responds well to throttle, the idle does not hang, and the bike is generally very responsive -- running better than it has since I got it. Also, once warmed up, the bike starts with no problems. So this only happens at first start up.
Having to tinker with the idle screw a bit is not that big of a deal, but the symptoms are so contradictory that it concerns me. What might I look into to root out this problem. Is it just a lean idle circuit? Forgot to do a plug chop this weekend, but I will do that anyway. Last idle chop that I did, however, came out pretty good, finally losing that richness that plagued me.
Before I get the "usual suspects," I adjusted my valves, fully cleaned and rebuilt the carbs, have jetted the bike for pods and exhaust (though I continue to fine-tune the idle circuit), pet cock works fine, electrics are tight (with coil relay and Dyna-S). After my many "Noob" threads, this is not my first rodeo
. Not to say that there won't be first rodeos for me in the future, of course.
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