Engine stutter at high speed
 

G´day all.

Touring south america with a 2003 KLR650 with only 6K on the clock and in need of advice. When I roll on the throttle at high speed (120 km/h) I get what is best described as a ´bunny hop´ effect, which feels like the engine cutting out or stuttering. It only occurs at speeds +120. Has anyone experienced this or could suggest some troubleshooting steps.

Initially regulator was the suspect and changed, but problem still remains. Travelling with a mate on a 1993 KLR650 and we both recently did a pass of about 4500m. His bike had few problems with the altitude, aside from a little loss of power, while for me it was a real effort to keep the bike rolling, perhaps suggesting some carby issues?

Thanks in advance.

kind regards

Just a guess but are the post 1997/98? klr's jetted leaner to meet emissions this would possibly explain the stutter

Yes, definitely sounds like a jetting issue if the stutter is only occuring at altitude.

The first thing I'd be doing would be to compare main and pilot jets, needles, needle positions and pilot screw adjustments between the two bikes.

I do recall when I was up in the Andes that I had breathing problems in all gears at anything above 6ish, so no surprise here.

Garry from Oz.

update
 

Thanks for the time in reply, much appreciated.

I changed the air filter and cleaned the carby and it did make a big difference. Still painful at altitude and the real problem lies in the carby jetted too lean. I have not got around to drilling a hole to get to the mixture screw (really silly design)....no other complaints with the bike though.

Kindest regards