JD Jet Kit with Stock Airbox

[CreativeMoniker]

Searched the forums and didn't find a direct answer to this, maybe someone can point me to where it is if I missed something ?

tldr: is there anything to gain from jetting without the 3x3, and will the JD jet kit be appropriate?

Long version:

I have an 06 SM with the stock airbox (no 3x3) and an aftermarket exhaust from the previous owner (it's Leo Vince, I believe it's the X3 and a full system, but I'm not quite sure how to tell - it might just be a slip-on). I'm satisfied with the overall performance in terms of power and top speed and I'm hesitant to perform the 3x3 mod because a) I don't like cutting parts of my bike, perhaps irrationally but still, b) I heard it will make it a bit louder and it's already louder than I'd like it to be.

I WOULD like to improve the throttle response - at times I feel it lurches more than it needs to from close to open and vice versa, and I would appreciate it if it popped less on deceleration. I'm wondering if a jetting is in order - as far as I can tell, it's never been jetted but I don't know.

So: what do you wise people of TT think? Will jetting help me? Is the JD jet kit applicable here? I know the DynoJet comes in two stages, one of which is specifically for stock airboxes, but I didn't see that written anywhere on the JD kit so I don't know if it will only work for me if I do 3x3?

Thanks in advance.

[Boshwa]

I don't personally have the JD kit, so I don't know if they have jetting specs for a closed airbox, but since the aftermarket exhaust leans out your engine, richening it up will help its performance, and I know the JD kit comes with needles that superior to the DR-Z's stock needle.

[cowpie]

jetting will help it regardless yes ... enlarging the hole in the top of the box 'is' a stock configuration on the E model and the recommended jetting in the JD kit is assuming the 3X3 opening is there to be the most accurate, enlarging the opening is easy and it will not make it noticeably louder .. i was hesitant to cut on my bike at first also, but do just do it, take your time and do it cleanly and accurately, and the JD kit is a very nice kit i'd get that, and you will have great results and be glad you did it ...

[ohiodrz400sm]

A very simply way to cut the box is to heat a putty knife with a

Bernzomatic torch.

 

As mentioned above jetting will still benefit even if you don't do the 3x3. The bike is delivered from the factory jetted lean. Having an after market exhaust only leans it out more. This will cause it to run hotter and likely less powerful than if it was stock. I don't know about JD but the Dynojet SM kits used to come with instructions on how to jet with or without doing the 3x3. They were marketed as stage 1&2 combined. I have to assume that is still how they are sold.

 

 

 

[bumtarder]

The original DRZ400's equipped with the 39mm FCR carburetor had the 3x3 airbox from the factory.The '06 SM did not.All we are doing here with the JD jet kit is emulating the performance of the early DRZ400/DRZ400E models by modifying the airbox to match those bikes,nothing more.This is a necessary step to properly jet your bike and not limit the tuning.It doesn't make the bike louder.You should wear ear protection when you ride anyway.

Edited August 20, 2018 by bumtarder

[CreativeMoniker]

1 hour ago, bumtarder said:

You should wear ear protection when you ride anyway.

I do - I wear earplugs that are supposed to reduce 32 dB of noise, which is the strongest I found. I still wish it was quieter....maybe I'm just old and grumpy? I dunno.

[Barry Ries]

The JD kit instructions assume that you will cut the airbox.   If you don't cut the airbox you may need to figure out your own specs, and when you get a jetting kit half of the value of the kit is having had that stuff figured out for you

[CreativeMoniker]

20 minutes ago, Barry Ries said:

The JD kit instructions assume that you will cut the airbox.   If you don't cut the airbox you may need to figure out your own specs, and when you get a jetting kit half of the value of the kit is having had that stuff figured out for you

Thanks - I know the JD kit is highly regarded here on TT, but I'm debating getting the DJ kit because their Stage 1 is described specifically for stock airboxes and lightly modified exhausts, which is what I think I have.

[Barry Ries]

25 minutes ago, CreativeMoniker said:

Thanks - I know the JD kit is highly regarded here on TT, but I'm debating getting the DJ kit because their Stage 1 is described specifically for stock airboxes and lightly modified exhausts, which is what I think I have.

If you want to leave the stock air box alone, DJ would probably be a better choice.   As I wrote,  a big part of what you are paying for is having stuff already figured out for you.   So get the one that has figured out the configuration you want to use.

[BillDirt1]

Thanks - I know the JD kit is highly regarded here on TT, but I'm debating getting the DJ kit because their Stage 1 is described specifically for stock airboxes and lightly modified exhausts, which is what I think I have.

Get the DynoJet stage1 kit, works good with stock airbox.