Off idle skip

[Venturous Randy]

I am having a problem with the area just above coasting and pulling. If I am running on flat ground with just enough throttle to maintain speed, at say 30 to 45mph, I am getting a constant skip, but not like a single dead cylinder. When I give it just a little more throttle, it smooths out and pulls fine.

I have been thru the carbs recently and cleaned the pilot valves and everytrhing else. I have also synced them again today and they also look good with the rpm's up to 3,000 to 4,000. I have tweaked on the mixture screws, starting at 2 1/2 turns out and really can not tell much difference when turning them in or out. I have also worked on the diaphrams and have no holes. I also ran a full can of Sea Foam thru it today.

Is there any suggections?

Denden, are you listening?

RandyA

[cimmer]

just a thought.. Have you replaced you spark plugs and plug wires and boots. I noticed that when I replaced them on my bike, the low end was alot more responsive and the bike just ran better at slower engine speeds. This was without syncing carbs or doing any adjustments to them.

Rick F...

[Denden]

Yeah, Randy, I'm listening.

It sounds like a problem with the pilot screws, that's what the carbs are running on at that speed. But it might have something to do with the pressure sensor (vacuum advance). A lot of them get a vacuum leak in them, and with an '83, that would throw off the spark advance. I seem to remember you changed something...the TCI or the pressure sensor? If you have one of the Mite-Vac brake bleeders, you can use it to check your pressure sensor to see if it holds vacuum. You can also use it to check your YICS chambers to make sure they hold vacuum.

My '83 seems to run best with the pilot screws set at 2 turns out. With the bike running, you could try turning each pilot screw IN until you hear the motor start to slow down or miss. Then back it out until you hear it pick up again. Then add 1/4 turn. But even if you do this carefully, you'll probably end up about 2 turns out, or pretty close.

Vicki and I are thinking of taking a little trip down your way, maybe this week. Knoxville, Smokey Mountains, Blue Ridge Parkway. Not sure yet. I'll let you know, maybe we can get together for dinner or something. Never been to Johnson City. I hear you have some good roads around there?

[Denden]

just a thought.. Have you replaced you spark plugs and plug wires and boots. I noticed that when I replaced them on my bike, the low end was alot more responsive and the bike just ran better at slower engine speeds. This was without syncing carbs or doing any adjustments to them.

Rick F...

yeah, cimmer is right...replacing the plug caps with the NGK 5k ohm caps and new plug wires really helps. NGK plug caps are (style no.)XD05F Stock No.8072. The plug caps have a prong inside like a sheet metal screw, they just screw into the end of the plug wire. Just unscrew the old caps and screw in the new ones.

[Venturous Randy]

I replaced the wires a couple of years ago with real Yamaha wires and put on new caps. The plugs have been changed this spring. I have not changed either the TCI or the vacuum pressure sensor as the question I had earlier had to do with the ported #2 carb, which I went back to my old one. I got a PM from another member stating he had the same problem and he found a loose connection on his fuse panel and it took the skip away. I still need need to verify my sensor is still working ok.

Thanks for the comments guys, I got to leave for work.

RandyA