DRZ400 Carb re-jetting

[mattsdakar]

Hi there,
Any past or present DRZ400 owners done the 3x3 airbox mod and rejetting?
Not sure which size main and pilot jet needles to get.
My bike is the electric start model with a Keihin FCR39 flatside Carb
Any advise would be appreciated

Rgds Matt

[buggsubique]

Yeah I did the 3x3...sort of. I couldn't really justify cutting more out of the top of the box so I was happy just to remove the snorkel. Are you running a standard exhaust? I had a custom header & yoshi pipe which really opened the bike up from the standstill - the carb would give a squirt and she'd launch. My main jet was a 160 (quite big I think?), forget what my needle was. I probably could have played with it more as it did run rich, but on wide open throttle (ie the jet) that probably isn't a bad thing, just maybe could have sorted the mid range (needle setting) out a bit more

All in all I was happy with that and could't be fooked dynoing it etc.

[mattsdakar]

Cheers for that Buggs,
Have a T-4 pro circuit pipe fitted which came with a custom header which has the same diameter as the standard header???

[buggsubique]

check out my photo album and you'll see the size difference on the one I was running - it was fricken loud (and annoyed others) but it was great to ride.

[MXNUT]

Air box snorkel removed, rear muffler modified - needle standard and running a 155 main jet.
Noticeable power increase with minimum economy decrease

[dino3310]

http://www.kientech.com/
worth a look if you dont know them allready

[CrazyFrog]

Air box snorkel removed, stock rear muffler - needle standard and running a 155 main jet at present. I haven't pissed around with pilot jets at all.
It did have a Pro Circuit T4 on it jetted with a 161 main and needle on 5th clip, power was great but very rowdy and quite thirsty.
Put the stock pipe back on for road use (so not to attract cops attention) and was running too rich with the 161 jet, so down jetted to the set up I've got now. Power still good, economy better and quieter (boring but safe).
Google it on Thumpertalk and you'll find an array of setups for different power delivery, and common altitudes ridden.

[mattsdakar]

Thanks for the reply guys,
Have googled about all I can about re-jetting. Will probably buy a dyna-jet kit in near future and do mods by the book
Rgds Matt

[Morcs]

Dyno jet kit is a lot easier. Just put it in.. cut the 3x3 hole, remove snorkel and away you go

[Nda]

Hi guys I got a drz400e 2002 with fmf fcr39 slant carb..
What's a good jetting I read lots about jetting they a seem different. . I'm in Nz my main jet is 142. Polit is 45... just has a bit of bogging when I twist the throttle fast at any speed..... thinking of doing the 3x3 and rejetting. ..

[MXNUT]

Be careful about over jetting. Too many people go down this route and actually lose horsepower by the engine running to rich.

Standard jetting should be fine for a standard bike.

If you modify the airbox and put an aftermarket muffler on then you could try a couple of sizes larger 150 or 155 but I definitely wouldn't go bigger than that.

Start with the smaller size 1st, and see how that goes.....

[SVboy]

Thumpertalk is your go-to forum for DRZ400 info and jetting advice.

[Nda]

I was talking to a guy at a motorbike shop about the jetting, how I read on thumper talk about jetting he said that's in America other side of the world, he said the jetting in different he in nz, as the heat and air is different. .. and font jet to what they jet to... so it's got me abit lost really. ..

Sent from my SM-J120ZN using Tapatalk

[Nda]

I was talking to a guy at a motorbike shop about the jetting, how I read on thumper talk about jetting he said that's in America other side of the world, he said the jetting is different here in nz, as the heat and air is different. .. and dont jet to what they jet to... so it's got me abit lost really. ..

Sent from my SM-J120ZN using Tapatalk

I was talking to a guy at a motorbike shop about the jetting, how I read on thumper talk about jetting he said that's in America other side of the world, he said the jetting in different he in nz, as the heat and air is different. .. and font jet to what they jet to... so it's got me abit lost really. ..

Sent from my SM-J120ZN using Tapatalk

I was talking to a guy at a motorbike shop about the jetting, how I read on thumper talk about jetting he said that's in America other side of the world, he said the jetting in different here in nz, as the heat and air is different. .. and dont jet to what they jet to... so it's got me abit lost really. ..

Sent from my SM-J120ZN using Tapatalk

Sent from my SM-J120ZN using Tapatalk

[SVboy]

I was talking to a guy at a motorbike shop about the jetting, how I read on thumper talk about jetting he said that's in America other side of the world, he said the jetting in different he in nz, as the heat and air is different. .. and font jet to what they jet to... so it's got me abit lost really. ..

Sent from my SM-J120ZN using Tapatalk

DRZ400s are such a well known bike, and the affects of all the mods you can do on them that I would disregard the bike shops comments. I would imagine you can get a DYNOJET kit for your FCR that has all the needles and jets you would ever need. Fit as per forum recommendations. if it works great, if not experiment.