Vacume advance problem?

[metalman]

I have a 78 xs11-e the problem is when Im riding down the road at a steady rpm everything is fine, but, when I let off the gas and then throttle back up, the engine has no power. To fix the problem all I have to do is hit the kill switch off and on, the bike comes right back to life, or pull in the clutch let it come to idle and the same thing. I replaced the coils, spark plugs,ignition unit. Could any one help???

[dragxs11]

Can you tell if your hitting on all four cyls? If you aren't when this happens, I've had the same thing. It still happens to me when my bike is cold. I think it's due to an imbalance in mixture to one or more cyls. Floats too high can cause too much gas to get into a cyl. and flood it. I know it's wierd, but if you know how carbs work, you can grasp it. When the needle lifts, if there is extra gas in that port it will be sucked in. Why won't it go away unless you idle down? I don't know exactly, but after rebuilding my carbs. mine doesn't do it anymore.... unless a float sticks!

[Madness]

Sound like it could possibly be your pick-up coil wires. You should pull off you left side engine cover and check your wires for the hourglass symptoms and do the splice fix if they are broken.
Here is a link for the repair:

http://www.xs11.com/forum/showthread...=&threadid=122

[riverchub]

Madness is right. I had the exact problem. after I finally chased the problem down, I spliced the bottom wire. It worked fine for two years then the top wire did the same thing. A quick splice and shrinkwrap and it will be fine. I called my local dealer and a new ignition advance is $440! Just splice it yourself and you will be better off. If you need instructions- where to find it or anything, just let me know. I had the exact same problem. When I told people about the clutch they looked at me like I was crazy, but there it was. Good luck.

[Madness]

If you decided you want to replace the wires with new ones, Zanotti's had them a few yrs ago for just under $80. I saw a post earlier by a owner who picked one up from the local Yami dealer for just over $90. This is just for pick-up and wires only. You won't need to replace the whole ignition advance.

[riverchub]

My Yammer dealer told me it was all one part and I couldn't just buy the pickups. I asked specificlly if I could. I do a lot of buisness there and I don't think they would try to screw me, maybe there was a mistake. Either way, I think it will be just fine with the splices for a while. Won't it?

[Madness]

I got my pick-up wires at Zanotti's. Here is their link: http://www.zanottimotor.com/motorcycle.htm I haven't checked, but the BikeBandit web site may have it also.

[MartyA]

Yamaha parts fiche shows the pickup coil / wire as an assembly, with one part number, IIRC.

Brent was handing out pieces of replacement wire at the XS East. I think it is the same wire as found on multi-meter terminals?

I had the same effect last summer, here is what I found / did:

oil level - too much could cause a sorta cavitation, stopping the motor drops the oil back into the crankcase. I put in 6 quarts once, don't ask, please.

centrifugal advance - (think this is also called a governor in some of the manuals) take it off and clean it, mine was very sticky and would advance when I dropped the RPM, then revved it and let out the clutch.

Vacuum advance - mine was sticking. had a piece of grit in the race. Then I found a reallly small hole in the vacuum tube that would allow leak down over a few moments.

In all likelyhood it is the pickup wires, but you can check these things out quickly.