more on MPG & carb settings

Bill Magitz corbie at
Wed Jan 16 10:34:27 PST 2008

Steve , thanks man , now that's not just stepping up to the plate that there's a grand slam !!!  as for the main , a " custom " needle was used I had the work done at Knevel Customs , oh those chopper guys hahaha. well he said no charge for the parts he used just a swap of parts and that sounded fair enough. Ed no longer works there and the shop cares not a bit about my parts now.  I'll dig through the carb parts link for the right bits and a friend has volunteered to help ( for the cost of a case or two ).  I know what you mean by the dealer , I went and they pulled out a calculator and said $400 to start any parts are extra and here's the kicker "we can't guarantee it will run better , it may run worse or it may stay just the same " almost the exact quote.   the bikes a good runner outside of those fumes , sorry Jerry.  but the mpg just makes it all bad.  Steve thanks again I sure hope I can cure what ails the ole GPZ.

> ----- Original Message -----
> From: "Steve Northrop" <blackgpz at>
> To: gpzlist at
> Subject: Re: more on MPG & carb settings
> Date: Tue, 15 Jan 2008 17:57:11 -0500
>      Bill, do you know what brand jet kit? It's important for the 
> main jet size. Do you still have the stock airbox or pods? If he 
> put in what I think he put in, NONE of which is available in a 
> standard jet kit for the GPZ, you are very, very, very rich. I'm 
> surprised Hugo Chavez hasn't sent you a personal thank you note. 
> The 35 slow refers to a #35 pilot jet, which is the stock pilot 
> jet. If he put in a #40 pilot jet, you are extremely rich in the 
> 0-4000 rpm range. In my bored out, 12:1, ZX11 cammed, pod filtered 
> motor, I only use a #38 pilot @ 1 1/2 turns out on the mixture 
> screws. A #40 pilot at 2 turns is way too much. If he gave you the 
> #35 pilot jets back, you need to put them back in, especially if 
> you have the stock airbox, and set the mixture screws at 3 turns 
> out. Now for the main jet (150 main). If it is a Keihin/Factory Pro 
> main jet, a #150 is way too rich. Again as a reference, in my 
> highly modified motor, I only use a #140 main jet. The jet size 
> numbers don't cross reference exactly between the Keihin/FP and 
> Dynojet mainjets but a #150 would still be too large. The Dynojet 
> main jet they supply in their Stage 1 kit to be used with the stock 
> airbox and a performance exhaust is a #108. This makes you very 
> rich in the 7500-11000 rpm range. There is no mention of replacing 
> the needles or even shimming them for proper mid-range (4000-7500 
> rpm) fueling. So, you're very rich on the bottom and the top and 
> probably lean in the middle. No wonder it runs like crap. I suspect 
> your bike was re-jetted with whatever they had laying around, 
> certainly not with a kit specifically for the GPZ. No kits for the 
> GPZ are supplied with pilot jets (you must purchase them 
> separately) and no kit has 150 main jets in it. The biggest main 
> jet supplied with Factory Pro's Stage 3 kit for the GPZ is a 142.
>      Alas, all is not lost. If memory serves me correctly, you have 
> a performance exhaust and the stock airbox. Keep your eyes open for 
> a Dynojet Stage 1 jet kit on ebay, it works very well for your 
> configuration. If you didn't get the #35 pilot jets back, go here 
> and buy four of them for a Keihin CVK 
> carburetor. When you feel up to it, I'll walk you through 
> installing the kit. It is not difficult at all, the hardest part is 
> getting the carb rack on and off the bike. You've learned the hard 
> way and I will reiterate it for everyone else's benefit here: YOU 
>      Bill, don't give up your GPZ for a $100 worth of parts and a 
> couple hours of your time. It'll run good again, really it will.
> Steve in Western NY
> '96 GPZ1100
> '02 Daytona 955i
> '08 KLR 650
> "You Can't Fix Stupid", Ron White
> ----- Original Message ----- From: "Bill Magitz" <corbie at>
> To: <gpzlist at>
> Sent: Tuesday, January 15, 2008 4:01 PM
> Subject: more on MPG & carb settings
> after reading the recent postings on mpg/miles per tankful I found 
> out what I already knew, my GPZ is not well. I had a jet kit 
> installed and after a few stops at mc shops I got it close but not 
> to my liking. I get about 110-120 miles before I hit reserve ( mild 
> riding , hitting the throttle will yield less than 100 mile tankful 
> ) which is @40 less than before jet kit and tinkering which 
> translates to 10-15 mpg less. also I'm spewing some serious fumes 
> wherever I go. see if this makes sense to anybody , the last 
> mechanic who set the carbs wrote this on the work order ,  35 slow 
> 40 slow 150 main and 2 turns out on mixture , I'm to the point if I 
> can't fix I won't keep it. will the proper setting help me get the 
> mileage I desire ?  thanks much to anybody who can pass info on, 
> the GPZ is a blast to ride and I'd prefer to keep it and upgrade 
> the Intruder 700.   --bill m  in joisey still getting out on the 
> weekends !!!!
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