Jet Kits

dragracer1951 · Post by **dragracer1951** » Thu May 13, 2004 7:55 am

I just got my jetting sorted out, so I thought I'd share what I did... I have a 95 FZR1000, Wiesco 1040 kit with stainless Manley valves and spring and shim set from Orient Express and Clutch backet, V&H slip on with the EXUP still there, Dynojet stage one and I did the head work. The instructions that came with the kit said to start with the needle in the fourth groove from the top and the pilot air screw 3 turns out. (the kit comes with 120, 124, and 128 mains) Oh and by the way...these main jet numbers are Dynojet numbers and in NO WAY are the same as Mikuni numbers!!!! Well, I started with the 128 mains and it ran pig rich. Went to the 124's and clip in the third groove with the pilot air screw 4 1/2 turns out. ran fair on bottom but not well on top....went to the 120 mains, foutth groove, nad ran pig rich on bottom. Infact it fouled plugs in less than a mile.... Somethings wrong here!! Cleaned carbs. Went back to stock jets. (removed the air correctors in the intake bells... ran pig rich. Clean, clean, clean!!! put the 120's in clip in 2nd groove and pilot air screw 1 1/4 to see if I could get it to run lean, Yup...ran lean!!! Final setting with jet kit was 120 main, third groove and three turns out on the pilot air screw. Idles cleanly, no stumble off idle, no flat spot, and runs strong on top. This is at sea level and the temps were mid to high 60's Hope this helps someone else through the same situation!! Jim

dragracer1951 · Post by **dragracer1951** » Thu May 13, 2004 7:59 am

The key thing to getting this thing to run right for me was removing the air correctors from the intake bells! Just thought I'd clarify that Jim

exupturbo · Post by **exupturbo** » Sat May 15, 2004 3:40 pm

I'm struggling with jetting on my bike at the moment, I need big main jets to ensure some safety under boost but get missfire below 4000 rpm due to over rich mixture. I did have the stage 3 dynojet installed which had some small bungs that were fitted to the front of the carbs. These have now been removed and my main jets are 150 at the moment, but I still get some missfire under 4000 rpm when the bike and weather are hot. What controls the fuelling below 4000 rpm ? I've tried dropping the needles as far as they will go but still have not got it spot on <img src=http://www.ezboard.com/images/emoticons/embarassed.gif ALT=":o"> Mark

dragracer1951 · Post by **dragracer1951** » Sun May 16, 2004 7:19 am

Mark Have you tried turning the pilot air screw in a bit? if it runs worse when hot, it's rich. How many turns out are you and what size pilot jets also I thnk you are refering to the air correctos on the carb bells? Jim

exupturbo · Post by **exupturbo** » Sun May 16, 2004 2:14 pm

I have not touched the pilot air screw and it is as it left yamaha as for pilot jets, they are standard as far as I know. The carb bells have me confused. When you look directly into the opening on the carb at the bottom of the inlet are two holes, with the stage 3 dynojet kit you put some brass bungs in the left hand holes. These are what I have removed. Do you think turning out the air corrector screw would stop my bike from overfueling under 4000rpm with 150 mains jets? It is most definatly running rich at low rpm, but do to some teething problems I have not had any real time out on the road to tinker with the carbs. Thanks Mark

dragracer1951 · Post by **dragracer1951** » Sun May 16, 2004 3:46 pm

Yes those are the air correctors I would try cleaning the carbs a couple of times before I started thinking about pilot jets...And you turn the screws in not out to lean the pilots... My carbs got cleaned a couple times when I THOUGHT <img src=http://www.ezboard.com/images/emoticons/eek.gif ALT=":eek"> they were clean... Is your bike a big bore? if so then that could also account for some richness ...bigger suck at the venturi I would also see about lowering the needles one groove at a time. But in the mean while....clean, clean, clean..... Jim

exupturbo · Post by **exupturbo** » Mon May 17, 2004 12:48 pm

Thanks <img src=http://www.ezboard.com/images/emoticons/happy.gif ALT=":D"> I must have cleaned them 20 times, so I know they are clean. It has a 1040 big bore kit as well as the 150 main jets so I will try turning in the screws to see if that helps. I have had the needles as low as they will go and it did not make any difference, I'm now 1 clip from the lowest setting. Mark

cterror · Post by **cterror** » Mon May 17, 2004 3:14 pm

dragracer1951 i have the same configuration in my std 1000fzr engine. full sebring racepipe. 120 mains of the dynojet serie, needle in 3,5 groove (i have the plastic dividers). screws open 3. as im currently in the middle of the bigbore project, i was thinking along same lines... as to get the 128 mains at least!! thank you very much for this info.

dragracer1951 · Post by **dragracer1951** » Mon May 17, 2004 9:27 pm

I gotta tell ya... them 128's are gonna be WAY too rich start at the bottom of the scale with the 120's, no kidding Jim

cterror · Post by **cterror** » Tue May 18, 2004 4:42 am

just a thought, what´s the sizes of jets in an dynojet kit stage-1 for yzf 750 r? im going to see an yzf750 motor today and if the guy sells it for a reasonable price, im going to buy it. the 1040 engine will be put together eventually but i need the bike and an spare engine is allways good

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