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...
Trouble after changing cylinder head..
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Re: Trouble after changing cylinder head..
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
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
93 Yamaha FZR 600 - Track Project
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88 FZR1000, 90 FZR 1040, 03 Suzuki SV1000S, 06 R6 50th Anniversary
-in NOT AS MANY pieces for track, beater prep
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- ragedigital
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Re: Trouble after changing cylinder head..
+1haunter wrote:I cant imagine the cams would be differnet enough to make it like a whole crappier bike
Sounds like a carb issue. Either they're not on all the way or air is getting in through a loose carb boot.
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Re: Trouble after changing cylinder head..
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?

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

Re: Trouble after changing cylinder head..
never dealt with that cali stuff before....
if you give it a bunch of choke does it run even worse?
if you give it a bunch of choke does it run even worse?
93 Yamaha FZR 600 - Track Project
-in NOT AS MANY pieces for track, beater prep
SOLD
88 FZR1000, 90 FZR 1040, 03 Suzuki SV1000S, 06 R6 50th Anniversary
-in NOT AS MANY pieces for track, beater prep
SOLD
88 FZR1000, 90 FZR 1040, 03 Suzuki SV1000S, 06 R6 50th Anniversary
- megaloxana
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Re: Trouble after changing cylinder head..
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.
'92 FZR 600
Airtech R1 kit \*/ 520 conversion \*/ 14F-47R gearing
K&N pod filters \*/ Stage 3 jet kit \*/ Factory Pro shift kit \*/ Full V&H SS exhaust
Custom '02 R6 undertail \*/ YZF gas tank \*/ Raised via dogbones \*/ custom flush turnsignals
Full R6 brake set-up \*/ SS lines \*/ Progressive fork springs \*/ ZX2 coilpack
ADD YOURSELF TO THE OFFICIAL FZRONLINE GOOGLE EARTH MAP

Airtech R1 kit \*/ 520 conversion \*/ 14F-47R gearing
K&N pod filters \*/ Stage 3 jet kit \*/ Factory Pro shift kit \*/ Full V&H SS exhaust
Custom '02 R6 undertail \*/ YZF gas tank \*/ Raised via dogbones \*/ custom flush turnsignals
Full R6 brake set-up \*/ SS lines \*/ Progressive fork springs \*/ ZX2 coilpack
ADD YOURSELF TO THE OFFICIAL FZRONLINE GOOGLE EARTH MAP

