LF right setting on carb for YZ490

Posted by dm_js on January 3, 2007, 9:25 pm

please rate
this thread

Looking for the right setting on set screws for 1982 YZ490 2 stroke yamaha.
How many turns for air and gas???

Posted by e on January 3, 2007, 11:16 pm

turn till it starts to rev, then back off till it idles
smoothly. rev with the throttle and see if it settles down
to the same revs. after 100 miles check the plug.
easiest and best way i've found.

Posted by dm_js on January 4, 2007, 9:40 pm

I just installed a used carb and the set screws were turned in all the way.I
just need to know how far to turn them out so I can get it started...
I can adjust it after its running.

Posted by Fred W on January 4, 2007, 9:49 pm

dm_js wrote:

Ummm.  A little?

Start with 1 1/2 turns.  Tune from there.  Try using a Color-tune if you
can get your hands on one.  I had great success on a 4 cyl Kawi motor
getting the pilots set right using one of them.

--
-Fred W

Posted by e on January 4, 2007, 11:15 pm

you need the manufacturer's specs' try google.