81 1000g idles fine won't accelerate above 2,000RPM

[Anonymous]

My 81 1000g starts and idles fine, but won't accelerate pass a fast idle. It bogs down with a complete loss of power. The bike has been sitting for about 5 years, but the previous owner said it ran fine. The carbs have been cleaned - other than some foul varnishes, they seem spotless. Floats and eedles and seats were all cleaned. I'm thinking it's not the carbs. The sympton is similar to a car with a timing advance that isn't working. That is to say the effect is sudden and right across the board. Choke off or on makes no difference, although it idles faster on choke - I take that as a good sign. It's not as though it runs poorly, it doesn't want to run at all. Given the electronic ignition, I have largely ruled out an electrical problem, but maybe there is? Can you use a dwell meter to check if the advance is working? Any other suggestions. I think it's getting lots of gas, based on the amount I have drained out of the float bowls.

[Anonymous]

I have the exact same problem with my bike. It was sitting for two years, the previous owner said it ran fine, he drove it around alot, and i cleaned out the carbs, and just like yours, they were almost completely spotless, and its still doing the same thing. Problem is, i havent figured it out, the only conculsion i came to was bad coils.

Check all ur spark plugs, see if any are wet, my #1 and #3 cyclinders were wet. They were sparking however, but much weaker than #2 and #4. I checked the resistance of the secondary wires, and they were iwth in speck, but the spark was still not as strong as it should be.

Does your exaust smell like gas?

Thats really the only help I can be.. sorry.

I ordered new coils, so if that fixes the problem, ill let you know.

Hope it helps a little.

[Anonymous]

First, check that your air intake system is all clear and breathing well. Clean the air filter. Check how it runs then.

Carefully check which cylinders are firing by feeling carefully for heat near the exhaust pipe of each cylinder. Which cylinders are hot and which are not?

Michael

[Anonymous]

Make sure that you still have an air filter. The foam might have crumbled to dust by now. Without a filter it won't run. I made mine (81 GS1000G) out of quarter inch thick foam sheet. A few layers cut and glued into a box shape around the metal cage. Works fine.

Kim

[Anonymous]

Mine a gs850l, but it acted like that and the filter seals were gone and the spark plug wire caps were bad and it made the coil weak, Once i replaced the caps(about $6.00) it ran alot better.

[Anonymous]

yours wouldnt rev past 2,000 with the old caps on?

[KEITH KRAUSE]

Classic symptom of failing diaphragms. Will idle all day, but won't accept much throttle or none at all. If the diaphragm(s) fails, the vacuum can't lift the slides. If the slides can't lift, the throttle valves can't open. Look for the tiniest pin holes or cracks/loss or suppleness. Pay attention to how they are installed, very easy to put them in wrong too.

[Anonymous]

Would that also explain the plugs being wet? and the smell of gas in the exhaust? It also controls the air flow as well right? So it may be running far too rich if the diaphrams are bad?

[KEITH KRAUSE]

I'm not as familiar with the CV's as some, still learning, but this is how I understand. If it is a diaphragm problem, the slides won't raise to allow the throttle valves to open. At this point you're running off the pilot circuit completely. The pilot circuit will supply the right amount of fuel with the vacuum drawing fuel from it at closed throttle. But since the slides won't raise and the throttle valves can't open, the moment you try to open the throttle the only thing that will happen is you will increase the vacuum on the pilot circuit. This will draw more fuel. Without the valves opening, the air flow does'nt increase enough and you have a rich mixture that will make the plugs wet.
It may be something else but the symptoms the original poster described can be diaphragm problems. A very-very weak spark could do the same though. A spark that weak usually won't allow a "fast idle" however.

[Anonymous]

The plug boots break down after a few years and start to misfire. They will normally do it one at a time, but you can get lucky :? and have them all do it together..... maybe that will limit you to 2k.

It's worth replacing them anyway after more than twenty years.

Kim

[Anonymous]

yours wouldnt rev past 2,000 with the old caps on?

It would get up to about 3400 and i did fix severel things at once, Sparkplug caps all 4(2 were real bad and the other 2 were almost, now they are well within specs), air box seals(the filter seal itself and both side door seals and a ground from the RR to battery to the engine. but this was on a 82 850gl , i just figured i would throw in what happen to me to see if it could help him, since it sounded close to what mine did.