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Discussion Starter · #1 ·
This is what I have found out on my 2 500's
I modified both machines exhaust and air intake for more fresh air. The 03 500 has the dyno jet kit on, works great but pricey. So on the 05 500 I just bought larger jets, and shimmed up the needle .030. It's noticeably faster than before but it has a problem with the main exhaust/header pipe. It still gets so hot that it bends and eventually hits the carb and boils all the gas out...NOT GOOD! (stock main jet 142 after mod's 160) also larger pilot jets for both machines.
So I purchased another dyno jet kit for the 05 and compared the stock needle to the new needle. The dyno jet needle is quite a bit slimmer and the main jets they give you with the kit are different than stock jets( the part thats machined to size is shallower) These 2 differences make a huge difference in mid range for running richer, which is where we run our quads most of the time.
I always thought re-jetting was the answer (w/ stock style jets) now I think the jet-kit is well worth the price.
Feedback???
Tell me what you think...................tigger
 

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It sounds like what your saying all we need for the kit is the needle? My stock main is a 138 and I run a 155 main now, 45 pilot, and washer shim on the stock needle, 2 in snorkle and hmf exhaust with quit core in. I havent had boiling gas issue.
 

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Discussion Starter · #3 ·
Well, yes on the needle and yes on the new main jets also. It too hard too photograph and hard to explain. The screw in end of the dyno jet main jets is larger than a stock one (on the inside)same size threads. Even if the machined jet size's were the same, the inside part that isnt part of the jet size is still larger on the dyno jet. Not sure if it would make a difference or not. All I can really say is that comparing the 2 jets side by side, there is a difference. I'm guessing that there would be a difference when running a dyno jet needle with a stock style main jet.
 

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I think I know what your talking about. I have a Kehien main jet and a mukuni main jet in 155 and the mukini head is a little bigger but the same thread as the keihen. I found out because I got my pool of jets mixed up by accident.
 

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I have a DJ kit in both of my ATV's but in my DVX I am actually running a Mikuni main jet with the Dj needle, found it to be the one that ran the best. The adjustable needle is the way to go and yes the DynoJet main jets do have different taper/cut to them as well. Just out of curiousity what size DJ main jet did you install with the kit tigger?
 

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i have always runned dj kits, yes a bit pricy but they do the randr so i don't have to guess, just follow the instructions and away you go. a few have had issues with the dj kits but i have run a good 8-10 kits in same amount of different machine's with no issues
 

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Factory manufactured jets all the way, no way Dynojet can test all machines under all conditions per the instructions. I have rejetted all my quads and sleds all my Ski-Doo sled used Mikuni, quadracer used Mikuni, and my Pairie and AC 650 have had Kehin jet changes with great results. The carb manufacturer has a lot more time and engineers to get these parts correct.

I always modify everything I own (personal defect I guess) I used Dyno jet twice on friends machines (400EX and Ski-Doo MXZ-800) and I will never again.

My 2c for what its worth.
 

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Discussion Starter · #8 ·
In the 05 500 auto I used the 148 dj. This is the second header pipe to bend on this quad. It has to be running too lean in the mid range. The dj needle is quite a bit more slender and hopefully it should take care of the mid range lean condition, the 5 slots will help with further adjustment if needed, also Its too cold out to try it yet. I have had great luck with first kit, I think they are over priced though.....tigger
 

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Discussion Starter · #9 ·
Took it for a test ride, 25 mile per hour tops,
Removed carb again, the diaphargm on top didnt seal quite right, repaired that( and that's not easy) replaced carb and it goes again! runs really good. Now my temp light flickers a bit, no worry, its still has warranty.
 

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Randy have you ever had the cooling system checked out on the new 05? I wonder if there is an air pocket in it or bad thermostate casuing it to overheat and not the jetting?
 

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Discussion Starter · #11 ·
Well, it starts flickering at start up, and when its warmed up completely, I can see that its circulating just fine and not too hot. I think the temp sensor is on the fritz. In the mean time, it runs great.
 
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