81 gs1000l misfiring problem!

[Anonymous]

I just bought this bike and its my first bike. I have a problem that when i get to about 3000 rpms it starts to misfire, but if i hold it out it will stop missing around 5000rpms. I checked to see if the bike has points, but from what it looks like, its an electronic ignition. All the plugs are new. Do you think it is a carb problem? Any help or procedures would be greatly appreciated
thanks
tom

[Anonymous]

Does the problem more closely follow RPMs or throttle opening? Check it out accelerating, decelerating, in and out of gear If it always matches with the throttle, you likely have poorly tuned carbs. If it always matches engine speed, maybe an ignition problem (not so knowledgable there).

But it's important to understand the symptom. Throttle or RPM?

Michael

[Anonymous]

It is at all throttle positions, but it is worse with the more throttle you give it. A guy at the dealership told me to clean the air filter. So i did and it doesn't mis or anything anymore, but it has no power at all. It didn't have enough power to go above 50 in 5th gear. Any ideas? I checked all the plugs and they all look good.
thanks
tom

[crayonjota]

It is at all throttle positions, but it is worse with the more throttle you give it. A guy at the dealership told me to clean the air filter. So i did and it doesn't mis or anything anymore, but it has no power at all. It didn't have enough power to go above 50 in 5th gear. Any ideas? I checked all the plugs and they all look good.
thanks
tom

I too have a big fat misfire, fuel related. You have the CDI which doesnt promote any kind of misfire really. Now you have a gutless GS. Not good. Double check the airfilter is not blocking the intakes and mark the ignition timing and advance the damned thing all the way and see what happens.

[Anonymous]

how do you check the timing? Is there timing marks on the crank like on a car? I'm new to bikes, but i have worked on cars for many years. On the label under te seat it says that it should be 17* btdc. Is that what i am looking to achieve? Any help will be greatly appreciated.
thanks for the replies
tom

[crayonjota]

how do you check the timing? Is there timing marks on the crank like on a car? I'm new to bikes, but i have worked on cars for many years. On the label under te seat it says that it should be 17* btdc. Is that what i am looking to achieve? Any help will be greatly appreciated.
thanks for the replies
tom

Tom, I believe that somewhere on this site there is a comprehensive guide to ignition timing.. Yes. there is an inspection hole behind the ignition pickup coils, and both pickups are adjustable, clockwise to advance, anti to retard. Bikes are easy compared to cars, but still cause headaches. If you have worked on cars that long then this should be a no brainer! I had to convert my GS to points, and I have no timing marks. A couple of runs up the road with the cover off and a little experimentation with timing position yeilded results that I can live with. I have just a hint of pre-ignition on full throttle at about 3000rpm in 5th. So perhaps I could retard it a bit, but it pulls hard in each gear so my gut says its about right for me..

I slept on my problem (I just wanna ride) and think it is fuel starvation, so perhaps you could go through the fuel system and check the fuel filter and signs of rust in the fuel. These things suck down a lot of gas and any rust particles will give real headaches. Pull your plugs again too and see if you are running super lean or rich. If cleaning the air filter made such a drastic deterioration the fault should be easier to determin. Good luck.. CJ

[Anonymous]

slow poke

Check the advancer to see if it works,( if it has one) as well as timing, check the exhaust for flow, did you damage the filter while cleaning it? is it stock or K&N type filter, if stock replace it with a
stock one, if K&N follow the cleaning procedure, check for stickin slides or ruptered diaframs