You should listen to me. No, seriously, listen to me.
Join Date: Oct 2008
Location: Santa Barbara
Motorcycle: Blue 2006 GSX-R1000
Re: GSXR1000 loss of power and significant gas tank pressure
This is complicated because there isn't a good explanation of exactly how the EVAP system works and what is the function of the various parts. For example the Tank Breather Valve is actually a tipover shutoff valve, as is indicated in the K9 service manual. But not in the K5/K6 or K7/K8 manuals, even though it's the same part.
The E33 tank had three vents in K5/K6; a drain, a breather that ran to the gas cap, and a third that ran to the canister from a vapor/liquid separator in the tank. As best I can tell, K7/K8 only has two for E3 or E33. The service manual says that there's no breather hose but does have a line to the canister. However the E33 tank has a different part number. My best guess is that the drain line is identical but that the breather line is routed differently inside the tank. No guarantees but you might try looking for a separator mounted near the gas cap. This would make sense as the E33 tank capacity is smaller just as in K5/K6. Note also that the E33 gas cap is different. But I don't know how and have wondered about that for K5/K6 for some time. As far more E3 bikes were sold than E33, a used tank is probably an E3.
A relatively simple thing to try would be to disconnect the canister line to the EVAP solenoid and to the tank. Then plug the inlet to the solenoid and run a breather line from the tank alongside the drain line as is shown in 10-19 of the service manual. This should plumb things up like an E3. Test it and see how it works.
If it's not obvious, the E33 throttle body has extra hoses and the EVAP solenoid that are not present on E3.
Following along Samantha's theme, you ought to be checking for a kinked fuel line or clogged injectors. However in the later case I'd expect that to also show up in the fuel filter. Have you checked the fuel pump flow rate?
Last edited by BillV; 06-01-2013 at 11:23 PM.