Fuel starvation

[poshscooter]

I am putting together a ts1 for a friend. It is a 225 with a Scorpion pipe and a TMX35 carb. i have fitted a rear exit fast flow fuel tap (camlam) and routed the fuel pipe near the engine bump stop.

I have started it no problem, and if I rev it slowly it seems to rev cleanly. The problem is when i snap the the throttle wide open it dies. i have noticed a large air bubble in the fuel pipe near the carb inlet and when I look into the carb mouth when I snap the throttle open no atomised fuel is leaving the main jet. Yet if i rev it slowly i can clearly see fuel leaving the main jet. Am I missing something abvious? or is there a problem with fuel starvation? any help will be appreciated.

thanks
Darren

[nelson pk]

As long as you have no air leaks your problem could be....

If your using the cheap crappy see through plastic fuel pipe, it can let air in between the joints on carb and tap and cause a vapour lock however this is more likely to happen on the open road when riding and not revving standing still.
Take pipe of carb and check fuel flow. If fuel flow is fine re connect pipe. It is then likely that your pilot jet or main jet is to lean, also putting the clip on the needle down a notch or two can cure this problem but you will be too lean somewhere on the jetting.
Once you have sorted out the leaness on your quick snap of wide open throttle on the stand you need to carefully jet the carb on the road or take it to a dyno specialist.
Hope this helps

[Grumpy225]

I am putting together a ts1 for a friend. It is a 225 with a Scorpion pipe and a TMX35 carb. i have fitted a rear exit fast flow fuel tap (camlam) and routed the fuel pipe near the engine bump stop.

I have started it no problem, and if I rev it slowly it seems to rev cleanly. The problem is when i snap the the throttle wide open it dies. i have noticed a large air bubble in the fuel pipe near the carb inlet and when I look into the carb mouth when I snap the throttle open no atomised fuel is leaving the main jet. Yet if i rev it slowly i can clearly see fuel leaving the main jet. Am I missing something abvious? or is there a problem with fuel starvation? any help will be appreciated.

thanks
Darren

To me this sounds like a float height issue.

I know if the float is adjusted wrong it will starve the carb for fuel or can cause flooding issues. It might be worth calling a grown up and see if they have any insight on that. At the very least look at the float height and see if it looks extreme one way or the other.

[nelson pk]

Well its definitely lean. A 2 stroke running lean will do this every time. A quick snap of wide open throttle on the stand will cause an engine to cough and die through an air leak, lean jetting, possibly float height if you've adjusted by accident when stripping the carb.
I actually use this as a test on jetting sometimes as your suddenly giving the engine loads of air intake very quickly and it will show up a leanly jetted motor/air leaky motor/weak slide by coughing and dieing very quickly.