Hi All

I have a 2010 txt 50 boy.

Last weekend while my boy was riding, he was going flat out up a hill and it started bogging and back firing and popping. Low - Middle revs was ok.

So I have stripped the carb and used an airline on it, main jet is a 70.

Checked fuel pipe not twisted

Checked all electrics for dampness and all contacts correct

Sprayed contact cleaner in behind the flywheel but everything seemed dry i.e. casing.

Took off silencer and check for blockages

Checked the reeds all ok

Plug was looking a bit black but after clean does seem to be going a brown colour on the ceramic.

But still when I put the bike on the stand and rev as quick as I can and let off it seems fine, but as soon as its 3/4 it starts bogging like fuel starvation or when a bike is running too rich.

I am not really much of a mechanic, but I dont think I have done anything silly, and the bike has only really done about 6 hours work.

Any thoughts would be really appreciated !!!!!!

Cheers

Smudger

try a new plug,could be breaking down under load.

first stop a new plug must be tried

I have checked the gap and also the spark but agree I will go and get another plug today and test...

Thanks, I will let you know if it does work tonight.

One other thing I did notice is that the water level seems to have dropped I have filled back up not much needed to be added but will keep an eye on that aswell as I am guessing a water leak somewhere may effect performance?

Cheers

Smudger

Edited October 15, 201015 yr by smudger984

hi, you might try temporally disconnecting the kill switch. some styles have a tendency to short at high revs when they age.

good luck, Tim

Tank not venting

Fuel tap partially blocked ?

I have checked the fuel and that seems fine could blow easily down the breather...

The latest .....

Put a new plug in and after speaking to Gas Gas UK they recommened I run it at 100:1 50ml to 5 litres. So I have mixed up 5 litres with 50ml of oil and also changed the plug, the bog is almost gone and too be honest I think a fine tune tomorrow and the bike should be running nice....

Not very pleased with the plug cap it come off when taking out the old plug and the end is a wire coil (fits around the top of the plug) but the other end is just pointed like a nail and pushes into the HT lead, really thought it would have been made better than this.

Can anyone recommened a better plug cap or are they all like this?

Also little bit worried about only 50ml of oil in the petrol was running 75ml to 5 litres but I must admit lots of oil spat from the silencer and got all over the bike.

Got a trial tomorrow and will take my petrol as well mixed at 75:1, I will check the plug mid trial and see what it looks like.

Thanks

Smudger

I have checked the fuel and that seems fine could blow easily down the breather...

The latest .....

Put a new plug in and after speaking to Gas Gas UK they recommened I run it at 100:1 50ml to 5 litres. So I have mixed up 5 litres with 50ml of oil and also changed the plug, the bog is almost gone and too be honest I think a fine tune tomorrow and the bike should be running nice....

Not very pleased with the plug cap it come off when taking out the old plug and the end is a wire coil (fits around the top of the plug) but the other end is just pointed like a nail and pushes into the HT lead, really thought it would have been made better than this.

Can anyone recommened a better plug cap or are they all like this?

Also little bit worried about only 50ml of oil in the petrol was running 75ml to 5 litres but I must admit lots of oil spat from the silencer and got all over the bike.

Got a trial tomorrow and will take my petrol as well mixed at 75:1, I will check the plug mid trial and see what it looks like.

Thanks

Smudger

I too was suprised at the lack of oil to be premixed on modern trials but i suppose engine tolerances and materials have come along way since the 80's and also the bike doesn't spend 80% of its time flat out at sky high revs like road two stroke.

The only thing i could add is check for exhaust or carb inlet leaks. two strokes are very sensitive to an exhaust leak at the cylinder or soon after, my old ts would not run with only a tiny split in the expansion chamber.

I too was suprised at the lack of oil to be premixed on modern trials but i suppose engine tolerances and materials have come along way since the 80's and also the bike doesn't spend 80% of its time flat out at sky high revs like road two stroke.

The only thing i could add is check for exhaust or carb inlet leaks. two strokes are very sensitive to an exhaust leak at the cylinder or soon after, my old ts would not run with only a tiny split in the expansion chamber.

I will check that today .... I probably need to repack the exhaust silencer as well as I reckon if that much was coming out the end it must have soaked the packing???

Thanks once again for all your comments much appreciated when pulling your hair out with a bad running bike (and believe me I havent got much of it left )

Edited October 16, 201015 yr by smudger984

Last report

The bike did the trial and the colour of the plug is a nice tan colour !!!

The bike sounded sweet all trial and did not pop or back fire once.

The only disappointment is that the oil has gone milky again so I will need to strip and check the pump...

Cheers

Smudger