DR won't idle in cold

[warewolf]

Elaborating on ryan's comments... There's two "idle" screws... the idle mixture screw aka pilot (sealed with brass cap on USA bikes, but not local/euro) and the idle speed screw. Two-strokes have an air screw (in rich, out lean) but four-strokes have a fuel screw (in lean, out rich) which adds to the nomenclature issue. You can buy large-knob idle mixture screws for most thumpers, so you can adjust at will.

The idle mixture adjusts your rich/lean at idle, and for about the first 1/4 of throttle. This affects starting, idling and the response when you crack the throttle open off-idle.

If the mixture is bad, then turning up the idle speed will hide not fix the problem, and your off-idle response will still suck. Go to thumpertalk or keintech or something and read their Jetting 101. Essentially you want the idle mixture that gives the bike the highest idle speed, tweak from there. It will vary with temperature and altitude.

[NordieBoy]

I suspect not cause this is buried under a brass cap in the DR carbs. Start with the idle screw which is a plastic knob on the LHS (if I recall correctly).

Cheers R

Only the US spec bikes had the brass cap.

[Skinny_Birdman]

Had visions of it being petrol freezing in carb etc

It'd have to be a pretty cold morning to freeze petrol. -60°C, according to Mr Internet. Sorry, random act of nerdliness.

Cheers
A

[warewolf]

At the Brass a couple of years ago, it took two cups of coffee poured down the ignition switch to thaw it out before I could turn the bike on. The petrol was still sloshing about.

And that was about all their free coffee was good for.

[Taz]

At the Brass a couple of years ago, it took two cups of coffee poured down the ignition switch to thaw it out before I could turn the bike on. The petrol was still sloshing about.

And that was about all their free coffee was good for.

Surely they could have just given you hot water??

[warewolf]

I didn't discover either problem (bad coffee or frozen ignition) till back at the bike with both.

[meteor]

Good advice all round guys cheers, did turn idle speed screw up (about 3 or 4 hundred revs I spose) and no probs since, but here in AK it hasn't been that cold since... Don't want to muck around with fuel mix screw. Again to all, thanks. Oh and re the petrol freezing thing birdman, just a guess on my part but at about -3 degrees with cold damp air and riding at about 60 to 80 K with wind chill.. it's pretty cold! (still not minus 60 tho... cheers)

[junkmanjoe]

simple fix, all good.

[meteor]

Ok a techo question next. My 250 has the carby shown above so must be similar to the 650. Both have problems as I read it. Mine was a real pig yesterday, almost deadened the battery and if it didn't have a kick start I'd be walking! Question is... does the 400 DRZ or KLX have similar issues or are they a better set up. Dare I say it, it's a commuter and I'm thnking of the DRZ400 motard? any advice?

[Bass]

Ok a techo question next. My 250 has the carby shown above so must be similar to the 650. Both have problems as I read it. Mine was a real pig yesterday, almost deadened the battery and if it didn't have a kick start I'd be walking! Question is... does the 400 DRZ or KLX have similar issues or are they a better set up. Dare I say it, it's a commuter and I'm thnking of the DRZ400 motard? any advice?

It sounds more and more like a little bit of crap in the idle passage. Send me a PM and we will arrange for you to bring it around and we shall sort it out - about 10 minutes worth at a guess.

It is very common to get a little oxide in the fine passages around the top of the needle.

The fix is to screw the needle all the way home while counting the number of turns (sometimes this is all that is needed) so that we have a record of the original setting. We then take the needle right out and give the resulting hole a quick blow job with the air compressor. Put the needle back in and adjust to the original setting. Take it for a ride and check the bottom end response. I believe that there is a tendency for the manufacturer to set them pretty much as lean as they will tolerate in the search for economy. (The idle mixture setting can affect your economy as it is typically working, to some degree, up to 1/3 throttle.)
Setting it fully lean can make the motor a little reluctant to lug at low revs and so inclined to stall at embarrassing moments. It also makes them intolerant of even the slightest bit of crap passing through.
Most importantly, with the choke system that is on those carbs, it can make them a prize bitch to start, especially on cold mornings.
If I am correct (and that is often not the case), the difference in starting is like night and day.

[meteor]

Thank you Bass. I still can't get over the difference. It's a different bike. The longest it's taken to fire is about half a second...that was this morning, a bit colder and sat out overnight (under the carport) I haven't needed the choke since. You're number is now at position 1 on my speed dial, cheers.

[Newguy]

Wondering if any mechanical gurus out there have heard of this before... I commute on a steel tank DR250. Usually runs well. Can be a bugger to start from cold but if I lean it to the left for 5 secs an pick it up it's ok. But with this really cold snap (0 degees in the morning) bike starts, runs on choke and then without choke in the carport but soon as I hit the cold damp air it won't idle. At lights or even changing down it stall's, even if running on the choke. but in the afternoon ride home, runs sweet as again? Any answers or fixes you're aware of? Have you heard of it before?

Had the same problem on the DRZ, but on mine the problem was a burnt out coil on the stator. The simptoms of this is weak spark, which makes it n bugger to start and idle in the cold. you can test this by taking out your sparkplug and holding it close to the cylinder head. you should be able to get a spark of about 10mm if all is still good.

Glad you got it sorted

[Bass]

Thank you Bass. I still can't get over the difference. It's a different bike. The longest it's taken to fire is about half a second...that was this morning, a bit colder and sat out overnight (under the carport) I haven't needed the choke since. You're number is now at position 1 on my speed dial, cheers.

You are very welcome mate.
If it doesn't need the choke at all now, I may have set it a tad too rich. Better that than too lean, but get back to me once you have had a chance to check the fuel economy. It probably won't make much difference on a 250 as you don't spend as much time on low throttle settings as the bigger bikes. However, if it starts running-on when you turn the key off, it's definitely too rich

If that happens, bring it back and we will discuss a refund over a beer.