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-   -   Hard starting XT600 (https://www.horizonsunlimited.com/hubb/yamaha-tech/hard-starting-xt600-105090)

gpower77 13 Feb 2024 16:32

Hard starting XT600
 
Hello,
I have an 88' XT600, and it is very hard to get started some times. Here are some things that are new on it, as far as parts.

1) New NOS Carb, found one in Australia on EBay, brand new in the box.
2) Intake boots are new, no leaks, verified with carb cleaner while running, no change in rpm, stumble etc.
3) Ignition coil looks to be new, does produce a bluish spark, regular while kicking over.
4) New spark plug

Cold start, I have tried it with choke on, and off both. If I do with the choke on, I will do 3 kicks, take the choke off, and it will pop off and run for about 1 second. You can kick till your dead, it will not pop off again, until you choke it again, kick 3 times, take choke off and it will pop again, one second and die. Eventually, after about 10 times of doing this, it will start and run, then I ease the choke back on, and it will run and idle at about 1500-2k rpm, until warmed up, then I take the choke off, it idles smooth and nice at about 1k rpm.

Hot start, no choke, have to twist throttle open about 1/4 to 1/2 turn open, and it will pop, after about 10 kicks, its running.

It is pretty frustrating to say the least. I have checked the decompression cable adjustment, it works fine, its not hard to kick over, I can hear the clicks, feel the resistance a bit, and I have noticed, if I go 2/3 of the way down, before "kicking" it, it does seem to help start easier, and not wear you out as bad. I am not sure what else to try, or tell you, but would like some ideas if possible. I would like to sell it, and be done with it, but I also dont want to sell it, if its not right.

Thanks

GP

Tomkat 13 Feb 2024 17:59

Check the compression. Poor starting performance can be caused by a burned valve.

Also consider selling it "as is" with the stated fault. You might get a low price but honestly at that age it's not worth much anyway, and you could spend a lot more fixing the fault.

gpower77 13 Feb 2024 21:35

Tomkat,

So I did go check the valve clearance, and only the LH exhaust was set correctly. The other 3 were tight. So I set them by the book, intakes a tight .004 and the exh at .005. Put it all back together and 3 kicks it was running. Let it warm.up good, and killed it. 1 kick it was running. I do have a light valve lash tick now at low 1k rpm, 1200 and up its gone. I'll run it a few days, and see how the starting acts, and listen/watch the noise. Thanks

xtrock 13 Feb 2024 22:34

Valves are 0,07-0,12mm inlet and 0,12-0,17 exhaust.

Grant Johnson 13 Feb 2024 23:06

Quote:

Originally Posted by gpower77 (Post 640687)
Tomkat,

a tight .004 and the exh at .005.

Note: That's in inches!

Quote:

Originally Posted by xtrock (Post 640689)
Valves are 0,07-0,12mm inlet and 0,12-0,17 exhaust.

That's in Millimeters!
----------------------

.07 mm = .0028 inches
.12 (or in Europe 0,12) mm = .0047 inches

.17 mm = .0067

So the two measurement specs are the same-ish.

Always good to note the measurement method :)

xtrock 14 Feb 2024 07:32

Just to point out i would slack the exhaust, have always adjustet on 0,10mm inlet and 0,15mm exhaust and never problem starting, the kicker was never a problem.

turboguzzi 14 Feb 2024 19:41

maybe some background will help, you are new here, we dont know you or how was the bike running/starting before, why did you change the parts you changed, millage, etc?


once its started, does it run well or other issues too?


have you ever measured the compression with a tester?



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