My 90 wont seem to hold a steady idle. it will idle at around 1200 then will jump up to 2000 then fall back down and sometimes stall out. My dad took a look at the bike and he said it sounds like one of my cylinders is misfiring. My carbs were just synced and completely cleaned and new plugs were installed. Sometimes the bike starts to run on all cylinders, you can hear when it does and thats when it revs up by itself. It also seems that if i lean the bike side to side it will either rev up or bog down and stall out. Could this be a plug wire or coil? Or does it sound like something else. Thanks for any help

 

i pulled the plugs today to take a look and the plugs on cylinders 1 and 2 were black and looked very carboned up. I checked on all the plugs by touching them on the cylinder head and they all seemed good, any suggestions?

 

Necro post I know. Having a very similar problem. Does anyone have any input?

 

were they wet? are your plug wires installed properly?

 

Two were wet two appeared normal I believe. Cylinder 3 wasn't fully plugged In. Now I have replaced all 4 plugs and I know the wires are on proper.

Bike was bought used, and abused I guess you could say. It has a vance and Hines slip on exhaust, drilled airbox, and a dirty orange dry paper airfilter. Im going to have the carbs synced soon and possibly get it rejetter since I have no documentation as to what has been don.

 

your bike was flooding the cylinders with fuel. When you cleaned the carbs, did you set the fuel mixture screws properly?

 

I never adjusted them. I only pulled the float bowl covers, and jets off to clean them.

 

Did you remove the floats and needle and seats?

 

No only the bowls and jets

 

Dude when you clean the carbs, you have to CLEAN the carbs. You need to remove the floats needle and seats and make sure you blow it out with compressed air when your finished.