For any of you guys having trouble with the YDIS system, post it all here.
Here's the Dutch Wikipedia entry for the YDIS (Yamaha Dual/Duo Intake System)
Dit is een carburatiesysteem met dubbele carburateurs op Yamaha-ééncilinder-motorfietsen. Pas vanaf halfgas gaat de tweede constant vacuüm carburateur meewerken, waardoor de motor meer brandbaar mengsel krijgt. In de autotechniek was dit systeem al langer toegepast, bij dubbele- of dubbelwerkende carburateurs en tweetrapscarburateurs. Voor motorfietsen was de primeur op de Yamaha XT 550 in 1981. Wanneer er puur aanspraak wordt gemaakt op het gasschuif deel kunnen zeer lage verbruiken gehaald worden. Dit gasschuif deel is vooral bedoeld vanwege de gunstige wervelingen wat de cilindervulling bij lage toeren ten goede komt en de motor beter doet oppakken.
I guess being South African has its advantages, so I quickly translated it:
The YDIS is a carburettor system with double carburettors on Yamaha single cylinder motorbikes. From half throttle, the secondary constant-vacuum carburettor opens up, which allows more fuel to reach the engine. In the automotive industry, this system was used long before it was implemented in motorbikes, with double or dual-stage carburettors. Its debut was on the Yamaha XT 550, released in 1981. Yamaha has claimed that this system reduces fuel consumption at low RPM's, while still providing good performance at higher RPM's. The intended purpose for this system was to provide the engine with better response at low engine speeds, providing a smoother engine pickup.
Getting two carbs to synchronize correctly can be a PITA, but once you get it set up correctly, it GOES!!
I just picked up a 1983 XT550 and plan on going through and cleaning it up over the winter. starts and runs great... until about 4000 RPM the engine cuts off. It seems like it is losing fuel. I pulled the carb (YDIS Y26PV dual carb - which I've heard can be a mess) and cleaned it up. There was a little debris in the bowl and the needle jet in the primary carb had a bit of gunk on it. I noticed that the main jet [what I believe is the main jet - short, stubby one in first photo] does not have any type of hole in it. I soaked it over night in carb cleaner and still no hole, doesn't look like there ever was one. Is this normal?
The pictures below show the 3 jets and what the corresponding ports they came out of are. I have been unable to find any good info on the jets for these. Any help is appreciated.
So I just recently took on a project with an xt550 and I love the bike but am having a very difficult time with the wiring. I bought this bike and none of the lights worked unless I disconnected the connector from the turn/headlights/horn switch on the left side handlebar. The owners before didn't bother to secure the battery and so when I was driving it home the battery fell out and a terminal broke. I wish I would have seen that but too late now. So I put a gel battery in and the headlights, instrument panel, turn signals, and taillight wouldn't turn on. I noticed that it would have a dim light when I would kickstart the bike but it would soon disappear too.
I have a diagram of the wiring and I took apart every single wiring apart to make sure all of the ground wire was connected and properly grounded. The previous owner basically cut the wires to a bunch of the lights and so I replaced every part except the kickstand safety switch and just connected it to the ground wire to always allow it to turn on. I put everything back together again and still no power to the headlights and the lights don't even dim slightly anymore.
My bike starts and runs perfectly mechanically but the electrical just won't turn on. I am trying to troubleshoot any possible problem and wanted to know if anyone has an idea why I am having this problem. Could it be a bad cdi, stator (I took it out and checked the coils and they look good), regulator rectifier, fuse switch (the button hasn't popped out yet), or is it something super simple like the flasher relay? I don't really understand electrical but I can't find a culprit to my lights not running at all.
Thanks to any who can help with this!