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Discussion Starter · #1 ·
Ok needless to say this is getting really old lol. Hopefully the high compression piston will give me enough power to satisfy me for a while. But any ways my mods are in my signature and i have 38 pilot 3 turns out 142 main. Stutters a bit but just wondering what you all think about that? Sound right? And another thing do high compression pistons have any special break in periods?
 

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All pistons require a break in period but as far as the sputterig is concerned.... if you pull the plate up that holds the Needle down you should have a tiny washer installed on it when you jet these carbs. it will eliminate the sputter if it dosen't then step up on the pilot to a 42.
 

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Discussion Starter · #3 ·
Ok well my carb is completely missing that washer your talking about. But your saying step up on the pilot. I'll give that a Shot. Should I try to get this washer? On a completely different note should high compression pistons make more noise? It makes more engine noise while running then I remember it making before.
 

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Try the slow jet first. I wouldn't think they make any more noise the washer usually comes in a jet kit so you may not need it.
 

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lol im running a 40 pilot and a 142 main and i think 2 1/2 turns out i will run it tomorrow and see how she does
 

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Discussion Starter · #6 ·
Yeah but eric dont u have a 400ex? Ive got a 300ex lol. But i put in the 40 slow left the 142 main and put the screw at 2 1/2. And im gunna give that a shot. Hopefully it works. Still to early to fire it up though so ill report back when i fire it up. Thanks Guys for all your help.
 

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Discussion Starter · #7 ·
And the noise i think is the piston. But my brothers 400 fired up and sounded the same. Its kinda like a helacopter almost. The sound im talking about.
 

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Discussion Starter · #8 ·
Ok ended up turning the mixture screw back to 1 1/2 and it seems to be running good. Only could start it. Still to early to ride around. Damn neighbors lol. But it starts a hell of alot easier now. Do you think 1 1/2 turns out is enough moose?
 

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The way to set the air mixture is to warm up the quad turn the idle up about 100RPM more then turn the air screw all the way in until it seats. Back it out 1/2 turn at the time let it set for 10 or so seconds back it out another 1/2 turn ect ect. you are looking for the highest idle you can get without turning the idle screw. once you achieve that turn it in 1/4 and reset the Idle. Ideally you should be at or around 2 1/2 turns. good luck. Also remove the black cover on the carb side, check your cable if you have any slack you will get that sputter.
 

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Discussion Starter · #10 ·
Any special technique or tool for that? Cuz I got like about 2 inches between my carb and my starter lol.
 

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It's a PITA on the 300EXs for sure. you almost need a little tiny home made screwdriver to do it or one of those angled screwdrivers. It's going to take some time but you can doit
 

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I made a screwdriver to adjust those pilot screws with. I used a piece of speedometer cable and one of those tips from a screwdriver with interchangeable tips and a short piece of pipe that fit over the speedometer cable and over the screwdriver tip. I glued it together and glued an old screwdriver handle on the other end. I can't remember if I glued it with a two part epoxy or if I used Gorilla glue. Anyway, it works pretty good.
 

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Discussion Starter · #13 ·
Sweet thanks fellas i would be screwed with out you guys lol
 

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Discussion Starter · #15 ·
Haha i gotta say thats the truth..........................................LOL
 
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