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Jetting order?

  • Main, needle, pilot, screw.

    Votes: 7 58.3%
  • Screw, pilot, needle, main.

    Votes: 1 8.3%
  • I don't do jetting and just want to know.

    Votes: 4 33.3%
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Discussion Starter · #1 · (Edited)
So I have heard some different things about jetting. I have my quad jetted pretty close but want to finish dialing it in. What is the proper way to jet it... start with the main and work your way down the throttle position? Or... do you start with the pilots and work your way up? Several people have told me both ways. Please post your reasons why if you choose one or the other.
 

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Discussion Starter · #3 ·
Yes I am pretty close. I changed all my jets down a little and its closer. Going riding tomorrow so I wanted to know where I should really be paying attention to. I guess I'll be looking at WOT tomorrow.
 

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I am unique
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If you are using an A/R meter, watch the meter when cruising at a steady throttle after a couple seconds, this will allow the ratio to stabilize, and you can tie the accelerator pump up so it will not affect the readings.............
 

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Discussion Starter · #5 ·
OK. So you are saying take the accelerator pump arm and disconnect it?
 

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Master of the Electron
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For those that didn't read his sig (as I first didn't) he's running FCR carbs which do have accelerator pump, stock carbs don't have them.

I prefer to guess at best jetting and install. Then I work on getting it to idle well, then work at WOT via mains, then mid-throttle via needles.
 

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you get it roughed in then start at the top and work down. What happens when you get the screw right then change a pilot jet? You have to go back and adjust the screw. Same for the needle you get it right then you might have to go back and change the pilot jet, then adjust the screw since you just swaped pilots. Well then you get the right main found then have to go back and adjust the needle wich then could require you to swap pilots, and lastly you fine tune the screw.

you will end up working from the top down. Just depends on if you want to do it the hard way or not.
 

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Discussion Starter · #9 ·
OK that makes sense. I had always thought you started at the bottom and went up because the jetting was a cumulative volume (WOT was all the volume from mains, needle, pilots and screw). The way you explained it makes sense though.

Willy - How am I supposed to test it at WOT? When I did a WOT run yesterday my RPMS got up in the 8500-9000 range and were still climbing? I don't want to blow this thing up.

BTW- my WOT run was racing a YFZ450... we raced a couple times on different surfaces. Neck and neck though 3rd gear. As soon as I grabbed fourth I would just walk away from him :eek:. When I was about 3-5 lengths ahead of him I would be just going into 5th :D The first time we raced I didn't think that he was trying. Then when I asked him about it he told me, "I was giving it my all but you just pulled away... do you have anything done to that?" :D
 

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OK that makes sense. I had always thought you started at the bottom and went up because the jetting was a cumulative volume (WOT was all the volume from mains, needle, pilots and screw). The way you explained it makes sense though.

Willy - How am I supposed to test it at WOT? When I did a WOT run yesterday my RPMS got up in the 8500-9000 range and were still climbing? I don't want to blow this thing up.

BTW- my WOT run was racing a YFZ450... we raced a couple times on different surfaces. Neck and neck though 3rd gear. As soon as I grabbed fourth I would just walk away from him :eek:. When I was about 3-5 lengths ahead of him I would be just going into 5th :D The first time we raced I didn't think that he was trying. Then when I asked him about it he told me, "I was giving it my all but you just pulled away... do you have anything done to that?" :D
The rev limiter should shut it down around 9300 rpm..............
As far as high rpm usage, my oval tracker pulled right up to 9300, I thought that was high enough, so that is where I programmed the rev limiter to shut it down, I believe yours is similar......
One more thing to note is running at WOT throttle doesnt mean you need to hit the rev limiter, it just means you need to have the throttle wide open in the upper rpm, say 6000 and up, and do your A/R readings.
The statement you made about all the jets suppling fuel is accurate at WOT, but the pilots are so small compared to the mains that you shouldnt notice it if they are to small and then decide to go larger at WOT, most needles are designed to flow adequate fuel at WOT unless you do not have the proper needle in the first place as comparing stock to aftermarket needles.
For instance, if you use stock jetting and install an aftermarket exhaust, airbox elimantor kit, and do some porting, your engine may not even want to run and should you get it started, it wont rev up, this I know from experience, so now if you install large mains say around 200s you may get the bike to rev up using stock needles if you have them to the top and have increased the pilots accordingly, but since the needles wont supply enough fuel at WOT when they are adjusted properly, so you will have a compromise here. What I did in 2001 when I purchased my first Raptor was to sand down the stock needles at the tip to allow more fuel at WOT, later I purchased aftermarket needles, which allowed more fuel flow at WOT throttle and also were a bit thinner in the mid part of the needle so I had better fuel control throughout the entire throttle range..............
 

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Discussion Starter · #11 ·
Ok. I'm using the needles you recommended in my setup. As far as the WOT, it revs so fast on the top end that if I were to measure the A/F at 6000 rpm I would probably only be about 1/2 throttle. This thing is an absolute monster above 5-6000 RPM so if I push it to WOT in that range it jumps to max RPM really really quick... to quick to get a stabilized reading.
 

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You need to do it while riding, not revving in the garage.
 

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Discussion Starter · #14 ·
This is while riding it. Maybe if I was 50lbs heavier and had brand new tires it wouldn't just break the tires loose. Even on asphalt the rpms/bike just take off. Maybe I'll try a different timing curve to see if that keeps it from revving so fast.
 

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This is while riding it. Maybe if I was 50lbs heavier and had brand new tires it wouldn't just break the tires loose. Even on asphalt the rpms/bike just take off. Maybe I'll try a different timing curve to see if that keeps it from revving so fast.
Your not supposed to complain about it revving to fast. I just run mine down the road at WOT tot get the reading but things start going by real fast at WOT. I don't have a RPM gauge though to tell my RPM's. I haven't perfected my jetting yet as I'm getting other stuff done so I can ride at the Rally this weekend:metal: I have 152 mains in mine with 62 pilots right now and it runs fine. Could be alot better I'm sure but it is close. Just gotta do some fine tuning and I think I could drop my mains to 150's but I don't have any...
 

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Jetting a 3 pluger is a bit diffrent than jetting a stock plug 660 Raptor. I found that smaller is somtimes better in the jetting. I droped a few sizes on my mains, still run #25pilots & DJ needles work the best for me, WAY better than the old GYTR needles I was running. & the revving is soooooooo friken fast & sooooo friken high, I cant wait to get my 3 pluger up & running again..
 

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Jetting a 3 pluger is a bit diffrent than jetting a stock plug 660 Raptor. I found that smaller is somtimes better in the jetting. I droped a few sizes on my mains, still run #25pilots & DJ needles work the best for me, WAY better than the old GYTR needles I was running. & the revving is soooooooo friken fast & sooooo friken high, I cant wait to get my 3 pluger up & running again..
Whats taking so long. I'm always fast getting my stuff back together. Only took 6 months this last time;).
 

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Discussion Starter · #19 ·
Banshee2Raptor - Do you have a trailtech or some way to see your RPMS? I still don't have the "bottom end" that I was thinking (<4000rpm). I guess I am starting to learn to ride it higher in the RPM range though. At first it was strange since I have been driving a diesel truck for a while which redlines way below my normal cruising RPM's with this! Top end is unreal though!
 

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Banshee2Raptor - Do you have a trailtech or some way to see your RPMS? I still don't have the "bottom end" that I was thinking (<4000rpm). I guess I am starting to learn to ride it higher in the RPM range though. At first it was strange since I have been driving a diesel truck for a while which redlines way below my normal cruising RPM's with this! Top end is unreal though!
I have ( or should I say had) a TrailTec, till it went south on me..My 3 pluger has more than enof low end power & as all 3 plug owners no the top end is amazing & they rev with athority. One diffrence between my build & your's is I run stock carbs & your running aftermarket.Not sure if that has anything to do with it..
One thing to keep in mind as to my ridding habit's, I rode a Banshee for 10+ years so I am used to "finding" the power. With a Banshee (any build) once the power is "found" youd better be hanging on because they are all or nothing, With this set up I dont haft to look hard ... at all:D
 
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