Thursday, April 30, 2020

Cool Your Jets!

Change of plans. I figured if I was going to turn the bike over to the shop in Martinez, they need to have 800-1000 miles on the new engine first, which means that I still need to get the bike started again. I've got plenty of time to work on the jetting, so I decided to get her going this week.

Not so easily done. I tried firing her up and she wasn't having any part of it. I was confident that the starting issue was almost strictly an air/fuel mixture problem, since it was running before. So I systematically started to change the A/F mixture keeping track of exactly what I was doing. I first started incrementally turning the screw out counterclockwise, but was having no success. I would periodically check the plugs and they were pretty dry. I did a spark test on her last night to confirm that the plugs were still firing. Yup. Everything looked good. Well, it can only be a small number of things- spark, fuel, compression or timing. I was sure that the bike was good for compression and timing, and I just checked the spark, so I was on the right track changing the fuel mixture.

Today I started turning the screw back in. Around one full turn out, the bike started acting like it wanted to start. As tired as I was from kicking, I continued my attempts after resting in between tries. After about 3 cycles, the bike started running again, but the idle really needed to be turned up.

I started working from the top of that pdf worksheet on carb tuning, recording meticulously everything I was doing. The bike was running its best around 0.75 turns out. I got the bike to idle at 1800 rpm's. I took it out for a ride working in the 0-1/4 throttle range. Everything seemed pretty good, so I put in a fresh plug and did a plug chop. When I pulled the plug out, it was so white! Not barely even a hint of tan! So this engine is idling super-lean. That's probably why it's having such issues getting started. And the A/F screw is almost turned in all the way, being as rich as it could go, while still having a little adjustment left to it. That was a sure sign that I need larger pilot jets. So I put in an order to EconomyCycle for a could of larger sizes of pilots, and a leaner range of main jets, because I'm pretty sure that I'm running really rich on top.

The jets should arrive in a few days, then I'll be at it again! The jets cost me roughly $50. If I could save that $500 from the shop cost, that would be awesome! I don't need it to run race ready, just good enough to be smooth and enjoy! I'll just take my time and be systematic about the process and I think I can have a good outcome.

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