DMC Alien Exhaust
- Thread starter Motocrossguy17
- Start date
what size jets do i need to find the correct one? just i am emailing a guy to see if he can get them for me in the uk. thanks
alright mate i got my jets today. im running 25:1 as well wondering should i still start with 300 main? also will i put the 35.0 pilot jet in as got a bigger pilot as well also running dmc exhaust,airbox lid off.
32.5 stock pilot will be fine.
You only need to change the pilot if you run a BBK, wild porting or exotic fuel.
25:1 usually requires a size bigger main jet, if you have a #310 fit it and play safe.
You only need to change the pilot if you run a BBK, wild porting or exotic fuel.
25:1 usually requires a size bigger main jet, if you have a #310 fit it and play safe.
thanks man
iv got 290-340. gonna try and do a plug chop but not sure if il be able to but il see 
Sorry to did up this old thread but I just bought this pipe. Are you saying that a #300 in combo with the needle on richest setting is where I should start?
300 or larger depending on your mods.
In winter I use the bottom slot in the needle , in summer I find it can come up one and my summer temps are around the 100 mark.
As always plug chop to confirm....
In winter I use the bottom slot in the needle , in summer I find it can come up one and my summer temps are around the 100 mark.
As always plug chop to confirm....
Uni air filter, vforce 4, needle is in the center, 32:1, stock airbox w/ lid no holes (I'm thinking about removing lid), soon to have dmc alien, main jets 290-330 are all in the mail. I'm in east TN... about 1500 in elevation.
So if I run the 330, think I can save myself the aggravation of moving the needle? I'm planning to plug chop right off thee bat.... I'm just asking about a starting place.
So if I run the 330, think I can save myself the aggravation of moving the needle? I'm planning to plug chop right off thee bat.... I'm just asking about a starting place.
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Your talking about two different jets. Your main (#330) controls 3/4 - wide open throttle.
The needle clip controls 1/4 - 3/4 throttle.
Here's a basic run down:
From 0 - 1/8 throttle is controlled by the pilot jet, and fine tuned by the air screw.
From 1/4 - 3/4 is controlled by the needle, and fine tuned by the clip position.
Main jet is 3/4 - WOT
Very helpful thank you, I learned something.
I moved the needle to the #4 spot so I'm GUESSING all is well. It runs great with the #330. I did a plug chop but the plug still looked new. I'm guessing it's because my straight wasn't long enough to peg out 6th? How much WOT time does a good plug chop need?
I moved the needle to the #4 spot so I'm GUESSING all is well. It runs great with the #330. I did a plug chop but the plug still looked new. I'm guessing it's because my straight wasn't long enough to peg out 6th? How much WOT time does a good plug chop need?
Contrary to popular believe, throw in a new plug and ride around for 5-10 mins and get the motor hot. A good chop should have WOT for 4-6 seconds in 6th gear.
Also, when you look at the plug, you have to cut away the threads and look at the base of the porceline. Even if the tip of the plug looks white, you'd be surprised by what you find after cutting through it. Only looking at the top won't give you a proper reading.
See picture above ^^
OK so I don't necessarily have to get the motor hot with one plug THEN switch to a brand new one for the chop. I can simply put it a new plug, ride with max amount of WOT, and then evaluate? I'm doing my best not to get on the road but it looks like I really should.
That pic, is that what I want or is it maybe a touch lean?
That pic, is that what I want or is it maybe a touch lean?
Great question! Always ask questions. The photos above in my opinion show a perfect main jet size for that given engine. A "light tan" to a slightly darker "mocha brown" ring about the thickness of a dime is perfect!
I don't know if you can see it but this plug just barely has a tint. It's not a dime, probably closer to a nickle. But it's so light!!! Did I not go far enough? I was on the road pegged out in 6th for a good 5-10 seconds then had to turn around and come back so there's 10-20!!! I'm not very happy. I would really like to think that my nickle thickness would have gotten darker than that.
The plug I took out for this chop was light mocha all the way to the tip.
The plug I took out for this chop was light mocha all the way to the tip.
Attachments
It is preferable to get the engine up to operating temperature with an old plug , then fit a new plug for the plug chop run.
Lookin
the picture is fine. It looks a little bit lean for my eyes. Grab a couple plugs and try again. How did it run? Any sputter in any of the RPM range?
the picture is fine. It looks a little bit lean for my eyes. Grab a couple plugs and try again. How did it run? Any sputter in any of the RPM range?
That's why I choose to leave the plug in the motor for 5-10 mins before a chop.just one WOT run isn't enough time to get a good reading. But there's more then 1 way to do a chop. Scurry through all the info you can find, and have fun!
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