Another nub jetting question

Ok very short background. 40 years old, mid life crisis, bought an old shitbox KLR250 rode it, fixed it rode it for about a year including maybe 3000k of dirt, wanted something with beefier suspension and maybe more grunt.

Bought a local 2001 DRZ400E that was in my price range (not much).

Im a newcomer to bikes but I managed to fix everything so far...but please be nice to me if I say something stupid.

Anyway its an Aussie E and I have a few issues / worries...

Firstly I think the bike has had a tough life from its PO (s). Remember that!

Ok so first problem. Surging, particularly cruising at maybe 1/4 to 1/2 throttle.

More than that it screams (its way loud) and goes like stink.

I pulled the carby and this is what I think it has

FCR (the slant one yeah?)

Main jet 165

Pilot 65 (???)

OBDXP needle 5th clip

Coast enricher still on

200 Main air jet

60 pilot air jet

Added a Wurz fuel screw and have tried it with different settings. At about 2- 2.5 turns out it touches the starter. Not good. I did drill the bowl to get the screw right in. (thanks TT)

The exhaust is stock. It had the stock baffle removed and drilled out and was basically straight through and freaking loud. I put a B&B end cap on it and its still loud, maybe not death levels now.

The bike starts ok cold, with the choke on and runs ok but until I hit the dirt I have to navigate about 10 ks of tarmac first, with traffic lights and its a bit of a handful. Once on the dirt its less of a problem and yesterday did seem to clean up a bit and would let me go easy rather than like a madman (which is fun, but out of my depth). For the second ride in a row, after an hours riding coming home on the blackstuff it stalled at every set of lights. Wouldnt start, so I pulled the choke and got home. I have some leak problems and other questions but this post is long enough to get me into trouble...


Fuel screw is for idle only.

I'll bet the needle jet emulsion tube (the part the needle slides in and out of) is worn. I'd also suggest trying a new pilot jet. While you have the carb off, check the float height, make sure the float needle valve is working properly and the float needle seat oring is in good condition.

Ok thanks William. I will check all that. Is it easy to get the tube out and what should I look for?

Is the OBDXP the stock needle and what difference do other needles make?

Brother in law has a CRF450 and said to check the float height too.

To be quite honest Id like to tune this bike for more mid range power rather than top end. I had a helmet cam on the other day and reviewing it later it sounded to me like I spent more than half my time in top gear about 70 - 90 kmh on sweeping and straight dirt tracks and was only using revs on small hills and tighter sections. That was backed up by the trip meter - 80km travelled in about 80 minutes, and there are some slower sections as mentioned.

Very easy to remove. Petcock off, drain float bowl. Remove the cap on the float bowl, remove the main jet, right above that is the tube. Be gentle.

You typical running speed is about the same for 80% of the riders.

Yes, the needle you have is stock, it is a good needle for your bike. Did you set the needle on the 5th clip opr was it there when you got the bike? What altitude and temps do you ride at?

Thanks again mate.

The clip was in the 5th postion when I got it.

Altitude not sure, but is not much above sea level. Its within 40km of coast no mountains or anything

I typically ride in the 20-30 celsius range, maybe less in winter.

It was 23C and 27C approx on my last two rides. This bike does seem to run a bit hotter than the KLR250 and the E has no fan.

How might the temp affect the bike if I want to ride it to work all year round (only 5km away), winter lowest is maybe 0 summer highest is maybe 40C (46 this year!)

William is going good.

Your'e in good hands Slug.

Have fun!

If the Aussie E exhaust is the same as ours in EU, its quite loud.

Both temp and elevation affect jetting sort of the same way. A hot day at the beach is cause you to be rich, a cold day at the mountains will cause you to be lean. If your bike is jetted for a cold day at the beach, you will probably be fine during a hot day at the mountains, within reason of course.

Hot = Less dense Air

High Altitude = Less dense air

Cold = Dense air

Low Alititude = Dense air

Make sense?

In your case, I'd set the clip on the needle to the 3rd from the flat/top of the needle. I'd also put a 160, possibly a 158 min jet in too.

William, I only got around to checking it out last night...damn it

The float bowl , valve looks good.

The emulsion tube seemed ok, theres some light scratching about 3/4 down the needle though.

But I realised that I stuffed up my original assesment of the jets. I thought I had a 65 pilot, turns out its the stock 45. The 65 is the choke jet. Yeah yeah, I know. Gotta learn somewhere. Anyway I cleaned up the jets. There was some crap in the pilot, a tiny spec. I set the needle to 3rd clip position.

Took it for a spin and it start great on choke, runs well on choke, but the problem is still there at 1/4 throttle. It idled beautifully though off choke. Fuel screw is 2.5 turns. Also, there seemed to be less bog when accelerating.

Do you think I need a 48 pilot or bigger even. Definitely seems lean at 1/4 - 1/3 throttle. Im going to get a new one today but want to know what size, and I'll pick up a 160 main as well as you suggested.

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