More tinkering
I finally ordered new pilot jets and installed them.
My bike's idle was noticibly smoother and more consistent. It also starts A LOT more easily when cold...I pull the choke, barely hit the starter button and it explodes to life. (vs. the old "yadda-da-yadda-da-yadda-da-Brum. yadda-da-yadda-da-yadda-da-Brum-Brum-Pop-Pop. yadda-da-yadda-da-yadda-da..."). I really prefer using the kick start, though.
It's still a little cold blooded. Before it is fully warm, it takes some coaxing to rev up but then it kind of takes off once it hits about 3500 RPM. So, for the first six blocks or so, it is kind of like the engine is a reluctant on/off switch, which makes it hard to ride smoothly.
Once it is warmed up, it runs pretty darned well. When sitting at the very longest traffic lights, the idle does eventually start to decline and I have to blip the throttle, but it's more of an occasional thing. I wonder if it is running rich at idle and it eventually starts to foul the plugs. However, this might not be the case because I currently have the idle mixture screws set to the leanest setting that results in the engine RPMs dropping cleanly, and my plugs look like I have the mixture about right. Maybe I'll check the carb balance once again now that I have the new pilot jets installed.
The headlight dims at idle, and the blinkers blink slowly at idle, so I was also thinking that I might also have a charging problem, causing weak spark at idle. I checked the voltage at 2000 RPM. The manual said it should be around 14-14.5V. I instead got about 13.5 volts, but the high beam was on and the battery was a little low. I charged up the battery and might test it again.
I also checked the charging system components.
On the open road, it runs beautifully! Last night, after work I met my wife for dinner at some of our friends' house up Rist Canyon. Rist Canyon is a crazily steep, maze-like twisting two lane road in the mountains. My bike just sang all the way up there.
My bike's idle was noticibly smoother and more consistent. It also starts A LOT more easily when cold...I pull the choke, barely hit the starter button and it explodes to life. (vs. the old "yadda-da-yadda-da-yadda-da-Brum. yadda-da-yadda-da-yadda-da-Brum-Brum-Pop-Pop. yadda-da-yadda-da-yadda-da..."). I really prefer using the kick start, though.
It's still a little cold blooded. Before it is fully warm, it takes some coaxing to rev up but then it kind of takes off once it hits about 3500 RPM. So, for the first six blocks or so, it is kind of like the engine is a reluctant on/off switch, which makes it hard to ride smoothly.
Once it is warmed up, it runs pretty darned well. When sitting at the very longest traffic lights, the idle does eventually start to decline and I have to blip the throttle, but it's more of an occasional thing. I wonder if it is running rich at idle and it eventually starts to foul the plugs. However, this might not be the case because I currently have the idle mixture screws set to the leanest setting that results in the engine RPMs dropping cleanly, and my plugs look like I have the mixture about right. Maybe I'll check the carb balance once again now that I have the new pilot jets installed.
The headlight dims at idle, and the blinkers blink slowly at idle, so I was also thinking that I might also have a charging problem, causing weak spark at idle. I checked the voltage at 2000 RPM. The manual said it should be around 14-14.5V. I instead got about 13.5 volts, but the high beam was on and the battery was a little low. I charged up the battery and might test it again.
I also checked the charging system components.
- Secondary winding: Good.
- Primary windings: Should be 600 ohms +- 15% @ 68 degrees. All three were actually 900 ohms at 50 degrees. Is this actually a problem? It's clearly not fully broken (not grounded out or fully-open). Is this enough difference to cause a problem? Did the electrical specs change when Yamaha went to a solid-state voltage regulator?
- Rectifier: Good
- Voltage regulator: This is solid state, so it isn't testable or adjustable like the old electro-mechanical unit. If I don't get better voltage readings with the high beam off and the battery fully charged, I might throw in an electromechanical voltage regulator from an old VW bug/bus/type3 and see if that makes a difference
On the open road, it runs beautifully! Last night, after work I met my wife for dinner at some of our friends' house up Rist Canyon. Rist Canyon is a crazily steep, maze-like twisting two lane road in the mountains. My bike just sang all the way up there.
posted by veloandy at 8:31 AM
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