Hey guys i have a 84 gpz900 and its doing something weird.
its always had a miss since ive gotten it,I cleaned out the carbs 2 times and used 8 cans of carb cleaner in the process,I checked the floats and all the internals,Ive synced the carbs but what happens now is that i still have a miss.
Now not only does it miss but after 20 mins or so it starts to run crappy and run like its down a cylinder,The engine runs thru the rpm range like its running thru molasses.if i leave the bike alone for a hour or so it runs just fine with the hesitation and slight miss still there but now it runs thru the rpm range like a normal 900 should and has all the power in the world.
Anyone have any clue where i can go looking?Im guessing something in the igniton but the idle is ok in either state.

Any help would be thanked

 

kinda sounds like a charge/charging issue. Same thing happens when you remove the alternator for track use and rely on the battery only. When the charge gets low, starts missing, etc and runs like crap.

 

I thought that too but the bike starts fine and it shows 13.6v on the meter when i run it up to 2k on the tach

 

That is 2k rpms, check that, I could be way off here. You mentioned 20 minutes of run time. Not rpm.
Check all screens, and vacuum lines. Heat on a system and volt drainage could still be an issue. You have a specific temp on gauge if this happens?

 

By cleaning out the carbs, did you take them all apart, clean and/or replace the internals? It still sounds as though the carbs aren't quite right.

And, what about checking your valve clearances? Maybe they are so tight that once the engine heats up, some of your valves start staying partially open?

 

i cleaned out all the carbs and didnt replace anything but took them apart and cleaned everthing inside,It still seems to run rich but i dont see where i can adjust the mixture.The engine temp guage is right in the middle and i have to check my valve clearances.Its just strange because even when the bike is running like its on 2 cyl it still idles very well,Just feels to me like im not getting fuel or something in the ignition is funky but ill take apart the carbs again and really go over evertyhing in detail

 

Id check the coils

 

Although it could be an ignition problem,maybe a faulty ground or whatever, it sounds to me like a stuck choke. I would't rule out the ignition, but I would look at the carbs first. If you did not remove the choke plungers before the eight cans of carb cleaner, you may have damaged them. This would acount for the rich condition, and the odd engine behavior.

 

i didnt know you had to remove the plungers but sounds like a smart idea to do,Ill get on that asap
Thanks

 

Hey, no problem. I was just on bikebandit.com looking at parts for my bike. I happened to see those plungers for around $10 a piece. Just in case you need them. I'd post a link, but I'm computer challenged and haven't figured that one out yet.