KR-1S.co.uk Forum

Hi Guys,

After getting my KR1S on the road I had issues with it bogging down between 4k and onwards with it being a little better at top end.

I took the main jets out and they were stamped 137. I have replaced them with new standard 135 jets from Kawasaki and tested. It seemed much better but still seems to stutter between about 4k and 7k. I figured possible over fuelling and moved the needle clip up one to second from top. I have tested again,and initially I thought the stutter and throttle response was better, but it now seems to have less top end punch and won't rev passed about 9k. Is it now too weak?

Starting and idle are fine.

The carbs have been ultrasonic cleaned, new float valves, floats set to correct height, new std jets, standard air box, standard air filter (I think) and standard exhausts. The fuel tap has also been stripped cleaned and rebuilt with new seals. Spark plugs and fuel hoses are also new.

This is the first KR1S I have owned and I have not ridden another, but from footage on YouTube the seem very smooth and happy to redline.

Has anyone else had this or similar?

Help!!!!!

maybe too much carbon built up in the stingers from the exhaust. if the hole is to small for the exhaust gases to escape, it also gives a stuttering engine.

JanBros wrote:maybe too much carbon built up in the stingers from the exhaust. if the hole is to small for the exhaust gases to escape, it also gives a stuttering engine.

Hi Jan,

Thanks, do you mean expansion chambers or silencers?

both.

but mainly expansion chambers, especialy the stingers

Hi Ian,

Had a similar problem at the beginning, pretty much in the same rev's you do.

It was the KIPS system that wasn't well adjusted (well it was completely desolate ).

Have a goog look at it!

Cheers
Mouser