Motor problems

[Paulyboy]

Hi there
I was just havein troubles with getin my 125 thumpstar started and wondering if anyone has any advice to help
It has spark and compresion and fuel getin to it and it still wont kick over or clutch start
Any idears?

 

[my67xr]

Welcome to Minirider's

First thing, drop in to our introductions thread and say hello
http://www.miniriders.com/general-chat/20824-introduce-yourself.html

How long have you had the bike, and has it been adjusted or tuned lately?
Last time you rode the bike did it have any problem's ?


Cheer's, Craig

 

[Paulyboy]

I have only had the bike about a month i rode ot then didnt go to ride it till 2 days after last ride it and it wouldnt kicker over or clutch start

 

[my67xr]

When you say it won't kick over, do you mean it won't fire like it's about to start?

While you are kicking it over trying to start it have you tried using the choke?
Any difference?
The carby has a good clean, oiled, foam filter on it yeah ?


What carby is on it, any of these ?

China Mikuni 22/26mm copy

Or a Jin-Ke, Shen-way, PZ19 or PZ22 china Keihin copy

After trying to kick it over, pull the spark plug out and see if you can notice petrol on the tip
Also when you say it has spark, is the spark bright blue/white or orangy yellow ?
And is the spark plug an NGK C7HSA or a crappy chinese Torch brand A7TC ?

 

[Paulyboy]

The carbie i have on it is the top one the japan one thats
I have tryed starting it with choke and it doesnt make a diffrence still dosent want to go
When i pulled spark plug out it was firein the colour white
The last ride i had on it was goin good it was rainin and abit wet could that have anuthin to do with it?
Thanks

 

[tmcpherson]

I would clean the carb and put FRESH gas in the the tank. give it acouple kick and see what happens. Next I would check to make sure make sure the gas is on, not turned off (iv done that a few times). I would try using starting fluid to start it and maybe get it running that way. Worst case, check timing. 99% of the time its fuel/air so triple check all carb related things.

 

[motodevo]

New plug first (epecially if its the chinese one it came with) even if it sparks outside the engine doesn't mean it will under compression. If it still doesn't fire you can eliminate spark as a problem, spray some aerostart into the carb while holding it open and then let go and kick it over, if it starts you most likely have a dirty carb. The pilot jets get blocked easily on pit bikes as do choke enrichment circuits, pull the carb down and clean it meticulously, fit an inline filter to the fuel line before you run it again to save yourself future dramas. When your finished riding from now on turn off the fuel tap and let the carby run dry, and then loosen off the drain screw at the bottom of the carb to be doubly sure there is no fuel left in the carb. Todays fuels tend to create a sticky yellow varnish in the bottom of your carb when they evaporate that will block up the smallest of holes (jets,fuel passages) in small bike carbs.
If there's still no joy, check your valve clearances, they might of closed up and and you may have a valve not fully sealing and therefore not allowing you to get full compression.

 

[Tig]

Any update on this?

I don't see this being as suggested, but check the kill switch. Mine was fried and caused the bike to not start no matter what. Just unplug yours to see if it will work when the K/S is disconnected.