RT 125 TICK OVER

[welsh mz biker]

My sons RT 125 just wont tick over, had the bike couple of months now,wudnt tick over when we first had it, thought it was the pathetic idea of a plastic round choke on the left handlebear, sticking, but what with other problems weve had with the bike now were finally getting down to the lil problems, hence the tick over, ive stripped the carb down , seemed fairly clean but blasted carb cleaner in all jets, needles etc etc so inside is spotless (you cud eat yor dinner off it lol) soooooooooo only thing i can think of is the idle adj screw which lets u adjust tick over on side of carb is worn ?? dont think its the carb, not alot of mileage on board for that, whatever happened to the ole choke lever on the carb idea,which i had on my harley ss250, suzuki gt 550 & gt750 triples, & my kawasaki z750l1, such a simple & faultless idea........sorry was reminising then!! oh memories hahaha........any ideas guys ???????

[djsbriscoe]

Hi,
I'm having the same problem.
I've tried the following and still no joy.
1/ Replaced all metal hose clips on carburettor hoses (including crankcase breather hose) with nylon herbie clips (google to find out more) to reduce vacuum leaks.
2/ Tried adjusting the float height several times, this only made things worse.
3/ Replaced air adjust screw parts and choke plunger and 'o' ring, no change.
4/ Had the carb ultrasonically cleaned, no change.
5/ Finally bought a new carburettor but still the problem persists.
I have also just bought an ultrasonic leak detector to trace any vacuum leaks as the idle speed on my bike is steady when the engine starts but increases by about 250rpm when it reaches operating temperature.
If I find what the problem is I will post it here.

David.

[DAVID THOMPSON]

by tick over do you mean in usa English idle speed ?

mine i set to 1900 rpm (udm)
and the fuel to air is at 2 turns
make sure there is not much free play the the throttle cable
but that the idle set in the side of carb is in control of the slide
the cable should lift it only after you turn it a bit
set float by the book
and use a stock air filter and store no items under seat in the area around the air box intake
i had a plug wrench and a shop towel stowed and mine ran like crap till i got it out of there
seem it was messing with the air flow
also check fuel flow line from tank may not be flowing fuel fast enough

dave
rt125

[welsh mz biker]

thanks both for your feedback, firstly, simon yeh sounds like we got same problem, i shall wait curiously for your finds! plus dave mate yeh tick over = idle speed in american terms hehehe.....yes have checked all that you mentioned even tried it with air filter no real differance really, engine just sounds throatier, as if its got K&N filters on, but i have noticed that the fuel flowing from the tank by the on/off tap that the fuel filter which is inline is clean no blockages etc but petrol seems very lil its just a trickle thru the filter/pipe never gets full at all, maybe the petrol flow isnt strong enough to allow tick over ??

[DAVID THOMPSON]

in some carbs the vacuum at speed will make more fuel flow