Fuel starvation will be the end of me :(

[grazo22]

Right If you've read posts I've done before you will know the storey of my agility. Essentially it is now running extremely lean and the exhaust gas is burning to touch. The compression is absolutely fine as I've swapped over the piston and bore from my old engine which ran perfectly until the crank splines went. I've also got my old cylinder head so essentially the top end is how it used to be. I had my old carb on it and it ran really lean though, cleaned and everything it still ran lean. Now i've swapped over to my spare carb which is also completely clean and it still runs lean. I've got a fresh fuel filter and there are no leaks on the vacuum lines or the air intake. Timing is all correct so I'm wondering if anyone has any ideas. I've got a 120# jet on order just to temporarily solve the problem. I'm beginning to suspect the fuel pump on the tank as the fuel filter is a clear one and only rides half full of fuel. I'll post a video later on today of it. There is plenty of power low down though. There is just none in the high rev range when moving although it revs freely to high revs when on the stand. Engine runs insanely hot though so i can only test it for a while at a time.

Any idea of help would be greatly appreciated.

Gray

[art]

Not sure about your model but kymco has a filter in the bottom of the petcock on others I've heard of this kind of problem with some.The fix is to remove factory filter and run inline filters.to small a main jet or floats only thing else i can think of.

[zombie]

It's all in the jetting grazo, The filter can run at less than full. Mine is rarely if ever full. The 120 may be too big tho. What size are you running now?

[marioG]

dont know if jet size is problem...im new at this....

got my 125 kymco rejet from 102 to 120 with open air filter....but no luck there..

after 80kph just stall.......

think theres no problem with jet size or air filter....exhaust is too restricted...

small tube is just not enough....

[grazo22]

Well I had a really good look at my bike this week as I have done several thousand times before and basically I ended up changing every part I previously hadn't. So I swapped over the CDI and hey presto my bike is working extremely well now and as fast as ever before Essentially where i swapped over the engines, there is a difference between the 2005 timing marks and the 2007. The preignition the 2007 cdi was producing was giving a false lean indication so thats what it appeared to be.

However I had already ordered my 120 jet by then so I will wack it in with a performance air filter to see the results.

Thanks for the help guys. My bike is finally running properly. Next project is to up gear it so anyone who knows where I can get a final reduction kit from........ I'm really just looking for indicated 80MPH on the motorway