GPZ on the Operating table Again

[The Big Spank Daddy]

At 76K miles it is finally starting to show its wear. Since I've had it, it has fould the plugs every 8K miles or so. At $15 each, it gets expensive. The bike was rejeted before I got it and has always run way too rich. After fouling a plug on the last SMR I finally decided to rejet it back to stock. I've been wanting to rejet it for a while just to get better gas mileage. It averages about 38mpg, 36 on a hard day and 40 it I baby it. I think it should get about 43+.

Fortunately I have the original jet kit with the original jets. So I get the carbs off. Every screw on them were loose. One bad throttle cable and the air box was just trashed! I disassembled the air box and finally figured out why it uses oil. The design of the PVC system litterally sucks the oil out of the case up through a special area in the air box through some tubes into the throttle boddies. Wierd set-up unlike any I have ever seen.

I cleaned the air box spotless. Cleaned the carbs inside and out, got the jets changed and put the original needles in the slides. Got the air box and carbs back on. All took about 6 hours, which included removing the tank and all the plastic.

Tomorrow, I plan on getting the plugs cleaned and installed. The petcock vacuum system does not work. The fuel is on all the time, so I'll get it disassembled and repaired why I have the tank off. Then we'll see if it runs any better. I think it is running a bit rough, but its one of those deals where it has happened so gradually that I really have not noticed it.

[pacman]

I love those GPZ's. I just can't resist a big engined Kaw. :-P

I wonder if the plug fouling problem might have been solved by the overhaul job you just did while keeping the carbs jetted at the same time? Ditching the PCV system and getting the carbs and petcock straightened out might have turned that machine into the smooth running beast it was meant to be.:trust:

[The Big Spank Daddy]

Yes, I should have done the carbs back when I did the valves several months ago, just got lazy. I love this bike it has always run smooth as glass. At 85mph you cannot tell the engine is even running, all you can here or feel is the wind.

It has an absolutely flat torque curve and has no "peak" power. It just pulls steady at all rpm in a nice linear fashion. The actual model designation is a ZX1100E. It has the same engine as a ZX11 with the exception of the cams and smaller carbs. That robs about 40hp but produces a glass smooth power delivery at any rpm. Over all the bike is a bit heavy, but it cruises like a Goldwing. A lot of people consider it a "crotch rocket" because of its looks. In reality it is very comfortable with bar risers, Corbin seat, euro windshield and factory simi hard bags.

[The Big Spank Daddy]

Got it all back together today and it runs noticbly smoother. Filled it up with fuel and now we'll see what kind of mileage it gets.