Timing Or Carb ? On Techno 250

[nevilletanner]

Hi,

previously my techno has had a problem where the engine kickstart kicks back seriously bad and often say under heavy braking the engine will actually run backwards,

also at low revs the engiine is fine but at high revs it just splutters and there is no power or increase in rev.

TODAY - i have pulled the flywheel and noticed the stator is set almost completely anti clockwise hense the vicious kickback and running backwards problem, i have set the stator to a middle possition and have completely eliminated

the running backwards problem,

But i now notice there is a dead spot at low revs (about 1/8th throttle) once above this is feels fine until you give it 3/4 to full throttle then theres nothing - no increase in powerand no revs.

also the engine is overheating - this has never happened before, the best way to describe it is that it feels like its on choke all the time (never uses choke even from a cold start).

I have stripped the engine down and noticed that there is quite a heavy amount of carbon even the spark plug (2 hours of use from new iridium plug) has this heavy coating of carbon aswell,

this evening i have removed all the carbon from the piston, head and barrel, there all shiny new now.

the carb has been cleaned and all the jets etc seem to be clear.

the mixture screw is set at 1.5 turns out from fully in , the carb needle is set in the middle groove, are these the correct settings and any idears what is going on ?

bike is mainly used 100 to 400 mtrs above see level.

many thanks

Neville

additional ::

the other thing i noticed is that the exhaust is getting very very hot - to the extent that after shutting down the engine its still burning off oil (exhaust still smokes)

the bike is a 97 model with a mikuni carb.

Edited May 2, 2010 by nevilletanner

[copemech]

Sounds as though you may have set it back abit too far. Find the mid point of the two, that should be closer as I recall.

Maybe someone has a diagram.

[dan williams]

What year Techno? Carb? Mikuni or Delorto.

The iridium plug is a waste of money. They are meant for use in cars that go 100,000mi on a set of plugs because the iridium is extremely hard and doesn't erode from the spark. In a premix engine you'll have to change the plug long before there's any advantage.

[stork955]

Gday, clean the exhaust system front to rear. If the internals were well coked up your exhaust will be as well and so cant breath. The bike is over 10 years old so it needs it anyway. Your carb and timing sounds right at this point however someone has been "fixing it" so it may pay to check they have not changed jets from standard -it seems rich too especially if it needs no choke to start. 100-400 meters above sea level will make no difference, you will see more change in atmospheric pressure from hot to cold days... Double check timingwith a timing light to confirm if you wish. Idle mixture screw will not effect full throttle, 1.5 turns is pretty close for a techno. Fuel/oil should be 70:1.

Keep us posted!

Cheers,

Stork.