yoshimura R77

[petersmith69]

I need some advice please. I've changed my stockpipes to a 4-1 yoshi (R77) sounds great, but now I'm getting a bit of backfiring. does anyone know what needs to be done or should be done (remapping, jetting...)? performance is great so far.

thanks

[TimF]

The popular thing to do is to block the pair valve. But my bike still backfires occasionally and it has been remapped and had the pair valve blocked.

image taken from www.busanation.com

[petersmith69]

thanks, i will try that.

[fasterfaster]

Tim check for loose joints in exhaust system could be drawing air in. Map could be to rich also.