Just a quick question looking for a few pointers. 
 

Been out on the bike a couple of times since I got it up and running. Starts fine, couple of kicks when cold, sometimes need to hold throttle open when hot but no biggie. 

Noticed that when accelerating, or part throttle under load, there’s a lot of popping in the exhaust. I’ve had a play with the carb screws to try and alter the mixture but no real change. Everything has been set to standard apart from the timing slightly retarded. 
 

Any pointers on what might be causing the popping? 

Cheers

Popping?  Is it 4 stroking?

 

2 hours ago, arthritic said:

Popping?  Is it 4 stroking?

 

Interesting, I hadn't heard of that before but having googled a few videos I wouldn't say it sounds like that, it's much louder pops, more like regular ignitions in the exhaust but not as often as every second stroke.

It's a 2005 bike so the silencer isn't repack-able unless I cut it open and find someone to weld it back up again. I'll have a look for any air leaks too just in case but it's got new gasket and o'rings for the exhaust.

I'm not sure what your experience is with trials bikes but they sure don't sound quite like other motorcycles, my 280 2 stroke has quite a pop sound as well and is completely normal. Otherwise I'd be possibly changing out a pilot jet? With a rich pilot circuit I have had very erratic backfiring (on a 4 stroke)

1 hour ago, Glayne said:

I'm not sure what your experience is with trials bikes but they sure don't sound quite like other motorcycles, my 280 2 stroke has quite a pop sound as well and is completely normal. Otherwise I'd be possibly changing out a pilot jet? With a rich pilot circuit I have had very erratic backfiring (on a 4 stroke)

Not too much but my sons Gas Gas sounds absolutely silent in comparison.