Cleaned the carburettors. Changed the spark and charged the battery (now it works for 10 tries maybe more).

The mixture screw is 3 turns out now and it fires up almost each time but dies. After 2-3 attempts it picks up rpm and it's ok.

Engine seems to be running good but I still don't like something ...

If I stab the throttle (neutral) it bogs a little and died once (maybe it wasn't completely warmed up ...)

The weather is really cold now going bellow freezing most of the time. Should I try 4-5-6 turns out on the mixture screw ? The needles (both) are in middle position clip and the transition between carbs is running nicely.

I suspect the engine is not revving as high as it should (I have to test this - I've mounted a rpm/hours gauge and it recorded 4800 rpm and I did quite a strong acceleration) I think this engine should go towards 6000-6500 rpm will have to test ...

The signs is giving me it could still be leanish running since it takes 2-3 minutes to run on choke when started from cold and it has those start and die symptoms ...

Quite hard for me to tune it since I have to wait for it too cool down completly so I can try again ...

When its warm is really a pain in the ass to tune that mixture screw since I keep burning my fingers most of the time ... I've made a small tool to adjust it !

I don't know if I should try buy a second hand pair of carbs just to test it ... I can't figure out if the choke is busted or not ... but the tests that I've made tell me its working, for example if the mixture screw is 3 - 3.5 turns out and engine is warm and I pull the choke it almost dies from rich mixture ... is this normal ? I believed it could run on choke but at higher rpm ...

I don't know how much popping on the exhaust is normal on this bike. I can try go leaner and try to see if it starts better ...

Will have to test further and try to see if I can make it work. I just want it to start on 1st or 2nd attempt and keep running ... the engine fires up like I said but it dies and it doesn't pick up rpm ...

I've set my idle rpm higher like I've been told here ... now is at 1450-1500 rpm (when hot).

I just can't seem to figure out the dying at startup is from lean or rich but I don't think a rich running engine can die at startup it can only die if its lean or the compression is low or the spark is weak ... please advice here

Also the spark when I've looked at it it was yellowish not blue ...

Your lean on the pilot jet and possibly the left needle . I'd go up one size(for now) with the pilot jet and raise the needle 1 groove .



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'86 XT600/3TB motor,,, '88 XT600, ,,'92 XT600e,,, '08 Husky TE510,,, '05 DRZ463,,, '95 KLX650 ,,,'96 KLX650

What if I back out the pilot jet to 4-5 turns out ? The results won’t be the same as going a size bigger ? (I’m not trying to be cheap) but they are quite hard to find in Romania.

Please explain me why is the effect different ? The shape and construction of the jet itself?

I can go richer on primary needle no problem !

Please take in consideration that when I open the mixture screw the revs eventually drop since the mixture becomes too rich.

Please also explain me which part that I’ve said in my previous post made you say that I’m lean on the needle.

I’m trying to learn which symptoms are the best for lean/rich conditions on this particular bike !

Thanks a lot !

The screw will only adjust up and down about half a jet size (at most) its only for finetuning, you cant compensate for a wrong jetsize.

After 3-4 turns out, the passageway is fully clear, and you wont gain more by unscrewing it further.

Which viscosity oil do you run? Perhaps a heavy 20w50 (the first number beeing the important one in this case) will give the engine too much "drag" here at colder temps. This is not the main issue, but could be adding slightly to your problems.

Make sure you have the correct idlespeed, perhaps go up to 1400-1500rpm, and shut of the fuel-petcock a couple hundred meters before youre home. That way you start with fresh gas in the bowl, and have optimum conditions for a good start.

Having said that, I've seen the "problem" before, its not a big deal that you have to restart once or twice in cold weatger, but I can certantly understand why you want to get rid of it.

The oil that I use is Motul 7100 10W40 (do you think I should look for 5W or 0W ? not sure if its available for motorcycles... I'm afraid of the friction modifiers because I could easily find 0W40 from a car engine)

The oil has 1000 km and I consider that is in pretty good condition since its still pinkish color.

I will try just for the sake of it to set the idle screw at 3.5 - 4 turns out and try to start the bike again.

I've bought a digital rpm gauge that attaches to the sparkplug wire and I've set the idle to 1450 rpm. Will set it to around 1500 rpm (when hot ?) and test again.

I will look for a 50 idle jet since 48 is what I think I have installed (but have to check first).

My needle jet has a very thin pointy end is that for the fine tuning ? and the holes in the jet are calibrated for exact delivery ? something like 35 units from the holes in it and the rest of 13 by screwing it in or out ?

I ask this because if I remember correctly the tiny pointy end was a little bent last time I took it out (it actually fell out because I forgot to count the turns ...)

Thanks !

This is a photo that contains an idle jet that is 99% similar to mine:



L.E. I just started the bike with the mixture screw at 4 turns out. It did start a little easier died 2 times and the 3rd time it managed to keep on running. Before it was 3-4-5 times it died then it started ...

This is a lean condition like I've been told and I have to find a bigger idle jet. At 4 turns out the idle is "stronger" (not higher) and I hardly need to use the clutch when moving the bike around at very slow speed.

Idle rpm dropped a bit and I had to set the idle higher to make it 1450-1500 rpm (maybe a half turn on the screw)

I will raise the needle (drop the clip) during daylight when I can take off the carburettors without freezing. Sadly I'm working outside and its quite cold.

As said that mixture screw is maybe equal to 1/2 jet size , you need a bigger pilot jet . The 48 should be fine , I can't remember what I have in all of mine but I know none are bigger than a 48 , more like 45 . You could have an airleak somewhere which is requiring a bit more fuel to make up for it . otherwise your fuel can just be that way and require a richer mixture. If you have a set of jet drills you can drill out the 48 about .001" and then file a slash across the number to remind you it has been drilled , I've done that a few times if it saves a bunch of messing around.

I generally have my idle set up around 1700-1800 , too low and these big singles get hard to keep running .


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'86 XT600/3TB motor,,, '88 XT600, ,,'92 XT600e,,, '08 Husky TE510,,, '05 DRZ463,,, '95 KLX650 ,,,'96 KLX650

I run 5w40 during winter, again, this is not the casue of your problems. I buy it from Louis.eu in Germany.

Ok cool thanks ! I will try to look for jets on LOUIS.eu or .de

Regarding the idle speed it's close to WR450 the setting that you use. I think it's 1700-1900 rpm for it.

Will try myself that and see how she starts

Thanks.

No jets on Louis for this carb, that was for the oil. KEDO - Performance Products have jets.

A #48 idle should be fine. Mine was #46 stock on my 2003 model

Theres cheap carb rebuildkits on ebay, something around 20-30$ for a complete kit, mine has worked flawlessly.

you dont mention checking the carb float level. surely you did this first before doing anything else?

I didn't adjust the float level. I think its only adjusted by eyeballing it few months ago.

I have the service manual for the bike and will check the float level and adjust accordingly.

It 8mm IIRC , you can put a clear fuel hose on the drain screw nipple and hold the other end up along side the carb going above the carb some. When you open the drain screw the fuel will fill the tube up to the level in the bowl . It should be 8mm(5/16" or .313") below the parting line of the bowl and carb body . So you won't have to take the carbs out of the bike to check.



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'86 XT600/3TB motor,,, '88 XT600, ,,'92 XT600e,,, '08 Husky TE510,,, '05 DRZ463,,, '95 KLX650 ,,,'96 KLX650

I started mine today after it sat in the cold for a while, it needed 2 restarts. No problem tho'

So I should just stop tormenting myself about 2-3 restarts ? And just live with it ? The bike is running great and during the autumn and summer was 1st start all the time.

I was riding 2 strokes in the past and being lean on 2 smoker is not fun at all.

My riding days are quite far apart recently ... I only start it once a week maybe once in two weeks and connect the charger to the battery to keep it in good condition.

I use the XT for mild off-road mostly and some long "walks" in the countryside.

Will definitely give this a try ! it's easy and like you've said I don't have to take the carbs off just for this.

Thank you !