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3x3 & jetting again...sorry

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Just reading through the dozens of threads on jetting and checked out the database. I see some run 140, and some 142.5 with the 3x3 mod and DJ kit.

I contacted Keintech and am ready to order the DJ kit and other parts. Jesse indicated stock jet should be okay for me. I'm just not clear on what main jet is stock.

I haven't opened my 's' carb up yet, so please excuse my ignorance. I just want to make sure I order everything I need, at once. Should I be ordering some other main jets?

I'm in Ontario at about 350ft elevation. No other engine or exhaust mods, although I might install an 'e' exhaust.

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stock should be a 142.5 main and 22.5 pilot.

the 142.5 is good if you have an aftermarket full exhaust. The 22.5 will need to be replaced with a 25 pilot.

Run the 140 main at your elev,, with a stock or modified stock exhaust

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Bronco,

What effect, if any, does the TEC insert have on my jetting selection. I have a 2003 S-model with a Yoshimura SS full system. I like to run it with just the screen, but in a lot of areas/ rides with sound tests I use the medium TEC insert. I switched to the new style insert (the cylindrical screen, not the hemispherical screen) recently.

Will performance differ much if I switch back and forth on the TEC inserts?

Today I am going to do my 3x3 mod and install DJ kit, keintech fuel screw, 25 pilot. I can't wait to ride it.

BTW, sorry to hijack the thread, but its a somewhat related qeustion.

Thanks!

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Having not seen or used the new TEC insert,,I'm just making educated guesses here :cry:

The med insert should not effect jetting,,, much if at all. Using the smallest insert,, will most likely require a smaller main jet.

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stock should be a 142.5 main and 22.5 pilot.

the 142.5 is good if you have an aftermarket full exhaust. The 22.5 will need to be replaced with a 25 pilot.

Run the 140 main at your elev,, with a stock or modified stock exhaust

Thanks Bronco. Now just waiting for my order from Jesse.

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Did my 3x3 mod this morning...working on the DJ kit now. So far so good, but I'm only 1 for 4 on the float bowl screws. :cry: Those things really blow. Time to get out the drill. Glad I got the allen head screws from kientech.

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Alright--got the float bowl screws drilled out. A tip for anyone else who has to drill 'em out; tape over every opening in the carb before drilling. Fortunately I had the sense to do this or there would be metal shavings everywhere.

Otherwise, the whole project went just the way everyone describes it here. But geezo, its not so easy to get the carb back in. There is really no easy way to reach the boots. But its all back together now.

The good news: it fired up right away, idled fine with the choke off, and sounded pretty good revving up in the garage. :)

The bad news: its been raining all day in southern california, and I'm not about to go through the gears on the street, in the rain, with knobby tires. i don't mind getting wet, I just have an allergic reaction to asphalt.

So hopefully tomorrow I'll be riding and comparing the performance of the mod vs. stock. :)

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I took a dremel disc to the screws than used a normal flathead, works great and there is less risk of damage to the bowl, then replace for allen screws!!!

As for the insert, I have a Muzzy and the quiet insert did not make much difference in the jetting, just the volume!!!

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Doesn't if seem like it's putting a fine point on things to distinguish between a 140 and a 142.5 main jet? My experience with jetting on my Sportster (which has a 40mm CV carb) is that it takes a drag strip or dyno run to see a difference between two adjoining mainjets in a series. and that's 1 or 2 mph in the traps but you CAN NOT feel the difference in the seat of the pants. Every serious drag racer I talk to felt the same. Of course, things happen much faster and violently on my Sportster then my mild mannered little S. Assuming the jet number has to do with cross-sectional flow area then we are talking about less than 2% difference. What happens when a 142.5 is used on the DRZ with stock exhaust compared to the Forum wisdom 140?

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it can create a rich stumble.the slide jumps up very fast and the main jet is in effect much earlier than you would think.

jetting a dirt bike has many more aspects than jetting for wide open throttle at the drag strip.if wide open throttle was the only area of concern,then yes the difference between 140 and 142.5 is minimal.

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"it can create a rich stumble."

Welllllll...OK. Are we talking about a really non-linear system here? My real point was the two jets are almost the same size. I still have a hard time seeing why a minutely larger jet would create this "slide jump". BTW, as with dirt riding most street riding isn't WFO and the same issues with part throttle jetting exist (believe me). Changing the main is just the start of the process.

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doesnt have anything to do with being linear.has to do with the slide being fully open long before the motor is at peak rpm.what little difference one jet size is at 10,000 is a big difference at 5000 rpm.

im not talking about part throttle,steady rpm.

take it or leave it.no issue for me.

feel free to do your own testing. :)

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