1983 Gpz 27k Starts but No Power!!

Wassup Kz Family,
brought a 550 gpz H2 back from a long hibernation (10+ years): Adjusted valves, cleaned carbs, new uni filter, stock airbox+ new boots , Assembly lube on top end, new battery, new plugs, new fuel and vaccum lines, fresh oil, Listened to all the advice about the cam chain tensioner and guide issue... Heres my struggle: the bike starts quickly even when cold and idles with no problem, BUT when i give it gas there is no power at all.. I was able to get through gears smooth but there was no power at all.. when i stopped, there was oil in my airbox [overfilled with oil?] .. i hopped back on[after cleaning] and it was a tad bit more power but still very slugish... Any ideas?? ××I also removed the emssions system as well, put tape/ caps over all ports on carb××

Oik in air box? MMmmmmmm.

1. is the clean air stuff hooked up? If so maybe wrongly and you are sucking oil from the valve cover to the box?
2. If oil is there, I am surprised it starts without fouling plugs. Could it be gas?
3. Check advancer to be sure it works correcty and is lubed.
4. Timing could be off.
6. Double check oil level, nut still unsure how oil would get there if the air system is off

Someone smarter than me will answer soon. Good luck.

R

Typically, oil gets into the airbox through the crankcase vent, not the clean air system. It is almost impossible for oil to get into the CAS. Even if it did, it would go out the exhaust system, not into the airbox.
If the bike sat unridden for some years before you got it, some of the piston rings may be stuck, thus allowing excessive blowby and a heavy oil mist forced into the airbox.
A seriously over filled crankcase, either too much oil or fuel from leaky carbs, can have the same effect.
Check the oil level. Remove the filler cap and take a sniff. If you smell strong gasoline fumes in the crankcase, then there are petcock and carb problems to address.
If it was a matter of too much oil, drain the excess and be happy.
If it is stuck rings, some gentle riding should free them up.

Maybe check the new air filter to see if the oil in the air box has fouled it up too..... synced the carbs ? Could you have capped off a vent on the carbs that you were not suppose too ? ....... hopefully someone that knows these carbs will comment.

Compression test would show if you have a broken ring. That can cause excessive pressure in the crankcase which can pump oil into the airbox through the crankcase vent (small pipe from transmission to bottom of airbox).

thanks man, ok ill test each cylinder for compression and see what the verdict is.. another mistake i made was i didnt cap of port 1 and 4 on the carb but i had the hoses from the emissions system connecting them both to a T and a main line heading out towards the back of the bike.. my mistake, would that create some insane vaccum ? i took it off and capped and i had no more oil issues lol, couldnt tell if it was from the hoses or I lost enough oil to solve the issue

Hard to say without knowing exactly how everything was connected. But if the crankcase vent (on the transmission going up to the bottom of the airbox) only connected to the airbox, and no other hoses went to the airbox, then the clean-air-system should not have had any effect on the crankcase pressure.

The airbox has a big hole near the top for the clean air system hose. When you remove that hose, you should plug that with a big cork. One of those large diameter vacuum caps from a parts store should plug it nicely.

If you incorrectly connect vacuum lines from the carbs to the valve-cover ports, that would either suck exhaust back into the intake, or suck air/fuel into the exhaust. It would probably run like crap and/or backfire a lot, but that should not really cause the oil pumping into the airbox. And if you T it and leave it open, you would suck fresh air into both the intake and exhaust... same result... run like crap and backfire.

alright.. so i did my best to plug vaccum ports 1 2 and 4 on the carb.. 3 is the vaccum to the petcock.. I just put electrical tape to block the hole in the airbox.. i rode it lightly till the motor was warm and i could see that gas was leaking from the petcock at fuel line connection, i also got more oil in my airbox as well again. it starts up no problem, but does not idle strong

Have you had the carbs off? Those are CV carbs. I would do the thumb test on the ports top back of the carbs to see if the slides drop fast or slowly. If fast the diaphragms are hard, torn or otherwise faulty. You don't have the stock exhaust on it so it may be too lean. Pics of plugs?
Steve

hey steve,,
ill test the carbs again, they were off the bike and the drops were consistant but i didnt test with the ports covered!! the intake and airbox boots were all hardened so if those were messed up im sure it might be a problem!! i put new plugs in a few days ago and will upload a pic in a sec.. thanks for the input

Personally, I would sort out the petcock first.
1- For safety's sake. I am pretty sure you do not want a giant fireball between your legs as you hum down the hiway.
2-If the petcock is not shutting off properly, it could be filling the crankcase with raw fuel when the bike is parked. This could explain the oily liquid in the airbox and the poor performance. It can also lead to more expensive problems.
3-If the vacuum diaphragm in the petcock is leaking, fuel can be sucked into the carburetor that the vacuum hose is connected to, causing poor performance.

If the carb holders and intake boots are hard, they are most likely leaking. They will need to be replaced before the carbs can be properly dialed in .