HELP!! Engine keeps cutting out??????



Hope someone out there can help


My engine keeps cutting out Farting and spluttering. It seems to run fine for about 10 mins then it starts to cut out, if I toggle with the choke it seems to want to go but then cuts out then it just dies. Let it cool down for a couple of minutes then she will fire up again and runs fine???

Engine was running great, but I must admit I did open it up, once. The engine did cut out at high rpm, doing just under 40 km/h. When this happened I eased off the throttle and the engine ran fine. unsure if this may have caused engine damage, as it ran fine the next few rides but then started to play up.

Generally it has been treated with a great deal of respect, kept under 30 km/m and only ridden for a max of 20 mins at time.

List of things I have tried:

checked carby for dirt or grit, main jet seemed fine but gave it a blast with air just to be on the safe side!

Checked for spark when engine is hot and cutting out. spark is fine.

checked plug gap running at about .032.

Engine history.

Engine has done about 200km and I am currently running 20:1 fuel mix.

Any Help would be greatly appreciated!!!!
Sounds like a restriction in the fuel flow.
Remove the float bowl and push the float "fork" up, now turn on the fuel petcock. Have a bowl or can ready and let the "fork" down. Does it flow fuel well?

Check to make sure the tank cap is venting properly.
Check your intake gasket(s).

If all that checks out, buy a new, QUALITY spark plug. (see "Optimize for your application" for a list of plugs.)

Let us know how it goes.