Following my RD125 mechanical anomaly that left me stranded on the side of the road on a long ride (see the story here: https://www.2strokeworld.net/forum/index.php?topic=6615.0), and then the post-event investigation that resulted in the bike being partially disassembled, I had planned to go further and make some maintenance updates "while I was there". In addition to the carb clean that was already done and exhaust removal, I had tentatively planned to pull the barrels to check & measure them and possibly hone and install new rings. And then to replace the seals, rebuild the oil pump, and check clutch springs, etc., etc.
However, due to the amount of work involved and the fact that I have way too much on my plate already, the bike ended up sitting in the garage awaiting attention with bits taken off for months. So, I decided just to slap it back together and get it back on the road since my borescope check and compression test didn't reveal any catastrophic issues.
The carbs were reinstalled with new OE flange gaskets, and new fuel hose and vents lines were installed, new repro rubber intake boots were fitted to replace the crusty 50-yr-old parts, spark plugs were replaced, and the battery was recharged.
rd125_carb_clean.jpg
rd125_intake_parts.jpg
rd125_boot_compare.jpg
rd125_carb_install.jpg
Since it had last been run with way too much fuel coming into the engine and likely washed the oil film away I squirted some 2T oil into the spark plug holes and added a little fresh fuel with weak pre-mix to the tank. After setting tire pressures I kicked it over and it fired up 3rd kick. Runs perfectly and no idle fiddling needed.
Took it out for a short test ride around the neighborhood and it runs great!
rd125_test_ride.jpg
The only issue I found is that I have a fuel seep at the front of the carb bowl mating surfaces. So, I pulled the carbs again and found the likely source is the ancient gaskets, which have not been available from Yamaha for many years. Float level was in spec and fuel was not coming out of the overflows. New repro gaskets are inbound from Yambits. Hoping that resolves the issue.
Excellent :cheers:
All back together with new bowl gaskets. No more fuel leak and the bike runs great again. 6-mile test ride and seems nearly perfect. :thumbs:
Just need to find the time to re-sync the carbs because after getting it all back together I had a throttle cable binding issue. After that was resolved by pulling the tank and moving the cables and fuel lines around the slides seem to be slightly out of sync. Otherwise good-to-go.