FZRSupport: the FZROnline Archive

I recently changed my cylinder head on my 1990 FZR600 to a newer head from a 98 model. It started fine and idled great but when taking it on a spin i noticed the rpm couldnt go higher than about 5k and it runs like poo. When I changed the head I noticed I have some sort of emisson tubing going from the exhaust port to the airbox and cyl #1. This is something the cali model has, but I don't think I have a cali model, theres no exup at least.
I decided to dismantle this tubing and plug the hole in the airbox and change the rubber boot on cyl #1 (so theres no hole there).
I'm running the 98 head with my 90 (cali model?) cams.... I've checked my CDI and it does not have the wire that the cali cdi has.
Could it be possible my fzr used to be a cali model and the old cams wont work with the 98 head? Remember, it runs fine in neutral, when I rev it and everything, but when I ride it it runs badly.


Update: Ran the bike today and it seems better (might be the fuel hose was kinked previously), but it sounds differebt. A little deeper and it feels lazier...

jetting?

a bike runs easier in N as it has no real load........


I cant imagine the cams would be differnet enough to make it like a whole crappier bike

haunter wrote:I cant imagine the cams would be differnet enough to make it like a whole crappier bike

+1

Sounds like a carb issue. Either they're not on all the way or air is getting in through a loose carb boot.

The stuttering around 5k was due to a kinked fuel hose...


It now runs okay, but I'm pretty sure it's lacking some power and it sounds richer. does anyone know I removing the emission tubing makes the carbs require readjustment?

never dealt with that cali stuff before....

if you give it a bunch of choke does it run even worse?

Your new heads may be more efficient in the way of valves sealing, etc. Therefore its a good chance you might need jetting. I went with from a 38k mile motor to a 3k mile motor, but I still used same jetting setup and the 3k motor was running really lean.