Hi,

I recently bought an 84 tt600, and it is not running properly.

The previous owner has had the bottom end completely rebuilt, but had only ridden it for about half an hour before deciding a tiny oil leak needed fixing - it then sat around for about 12 months. It has an aftermarket exhaust can.

I have completely cleaned out the carby and fuel lines with chemicals and air (there was lots of crap in there) and reset all the settings to factory. I cleaned the air filter, and the spark plug indicated that it was running rich.

It starts well and idles fine, but at about mid throttle range it starts to sputter and hiccup like it is running out of fuel. I played around taking the air filter off and it had no effect.
I then disconnected the black pipe that connects the secondary carby to the air box, and it now it runs really well, with more power across the range.

Obviously, I cannot run it without an airfilter - there is a problem here somewhere - what could it be, and what are possible solutions? I have been assured that it ran well, but tired, before it was rebuilt (and I do believe him...).

It now has heaps of compression (can barely turn it without the decomp) - could this and the aftermarket exhaust now be sucking too much air through? Will airfilter pods cure this? Is the jetting now wrong?

Any help would be much appreciated.

Depending on the aftermarket can and how much more free flowing it is adjusting the carb settings back to stock could be your problem. Sounds like a jetting flat spot to me.

Is it just a can or full system. You could try looking up settings for the can on the net.