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-   -   black smoke (https://www.horizonsunlimited.com/hubb/yamaha-tech/black-smoke-5694)

waverider 22 Sep 2002 01:24

black smoke
 
hello all,

my 1VJ starts up very easily when cold, however when it has warmed up it is much more difficult to kickstart. i have to open the throttle full and kick hard. it starts up but blasts out a thick cloud of black smoke.

any ideas as to the cause of this.

thanks.

OXXT 22 Sep 2002 09:47

black smoke is generally fuel, sounds like when you open the throttle it gets a big dose of fuel which burns off when it starts. As to the reason why it needs so much to start i wound not know.

FredXTZ 23 Sep 2002 22:09


Your idle fuel/air mixture needs adjusting.
With hot engine, turn the small screw under the carb in until engine starts running worse, then turn it out until it starts running worse, then go back to a position in the middle.

------------------
Fred, XTZ660, Holland.

RichLees 24 Sep 2002 00:10

sounds like its running so rich that it will start from cold without choke, but then fail to start when hot. did you check the airfilter is clean? if its new, did you remove the bag ;-) is the choke cable properly adjusted?

FredXTZ 24 Sep 2002 15:04


Or maybe the choke piefie in the carb is stuck. Check that it's sliding in and out freely and fully [that's what she said last night too].

------------------
Fred, XTZ660, Holland.

david lambeth 26 Sep 2002 04:35

Hi.
Why are you having to use the kickstart anyway? A good 1VJ should start immediatly hot or cold on the electric start.
By now most 1VJs will have had so many carb "rebuilds" that you are bound to find somethihg that could cause bad starting.
Carb rubbers, float height, float needle jet o-ring (dries up and doesnt seal), choke plunger sticking or cable tight etc etc.
On the subject of black smoke on full throttle, most engines would do this anyway.
Also dont dismiss an ignition problem when warm - Quite common. Source coil windings usually, sometimes CDI unit.
Let me know what you find.
David Lambeth.


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