Problems cold starting 660

[atlej]

Hi

My black Panther 2002 is has problems starting when less than 8 deg C.
I bought it used one year ago. It has race can and "maybee" carb modifications. The previous owner didnt know for sure. Her is a description of the problem:

The choke is very sensitive. To start (cold in summer time) i always have to have full choke and then turn it completely of 3-5 seconds after it has started. Otherwise the engine stops again. When the engine is hot i can run it with the choke on again if I wanted to.

Now when the temperature is around frezing point it wount start at all. Around +5degC it may start but only if I give it just a litle bit choke. then If I am lucky it will idle for a minute until i can start to ride it. If I touch the choke or give it som revs it stalls again.

It semees to me that the engine is very sensitive to the fuel/air ratio. Why it doesnt start on full choke I have no explenation. The normal reason i suppose could be that it is to leen mixture ? But then full choke should solve it ?
By the way, if I use start gas from a can it will start even below freezing temp.

What should I do ???

[DAVID THOMPSON]

one problem i have found with cold starts is do not open throttle
any when cranking ... my rt125 and saxon tour get real upset with
open throttle at startup even with warm wx..

and almost every bike made has tooooo small of battery..
on the rt125 i use the ori battery to run bike and hook starter to
a booster pack in the winter so that the spark coil has a full 12 volts
when trying to start

also the rt125 is very fussy about the idle fuel air mixture setting..

the spark plug may not be helping
i use dpr8ea-9 on the rotax 500cc some i think use it on the 660 yamaha
motor

ar dave

[phlat65]

first thing is to check basics. replace the spark plug regardless of condition. make sure all the air boots are secure.

remove the choke plunger and clean it, and apply a small amount of silcone based lube to the 0-ring.

check basic carb adjustments.

is the air filter clean and properly (not overly) lubricated with good quality filter oil (not engine oil)

because it stalls upon throttle aplication when cold, I would suspect a lean pilot jet, or air screw.

mine will start on full choke @0 deg C. after 3-4 seconds, I can turn the choke all the way off, and it will run fine. that is what the manual says should happen.

sounds like someone has been mucking with the carb settings. I would go back to stock, and go from there.