Jetting advice please
Posted: 07:10 pm Jul 23 2014
I just recently bought a '90 KDX200. The seller stated he thought it needed rejetting for 3/4 to full throttle, he said he knew little about bikes but had cleaned the carb as the bike has been sitting for a couple of years.
It was dripping gas rapidly out the overflow so I took the carb apart, inspected the inlet needle and seat. The needle looked good, the seat looked like it might have some old gum from fuel on it. I made a small ball of very fine steel wool and cleaned the seat by turning the wool with a screwdriver.
The float was way low, about 22mm or more, he probably did that trying to stop the fuel overflow. The needle clip was in the top groove, again I expect an attempt to stop the overly rich condition caused by the too full float bowl. The idle mix screw was 1/2 turn out.
The carb has a R1172N needle, 50 pilot, 130 main. Airbox is stock. Mix is 40:1 dino oil.
The pipe is an FMF Gold Series Fatty with a Turbine Core muffler.
I set the float to 16mm, moved the clip to the 3rd groove, set the idle mix screw to two turns out.
The carb does not overflow now at all.
The bike has a lean spot as throttle is opened about 3/4 or full until it comes on the pipe. It doesn't stumble or blubber, just goes flat with poor acceleration. If I pull the enricher out the flat spot goes away while of course it is rich at lower speeds. With the enricher out it pulls smoothly right on up to on the pipe.
It pulls hard at lower rpms and hard after getting on the pipe with the enricher off.
I live and am riding at 9,300' elevation but the 130 main seems too lean to me, can't imagine who put it in there as the bike came from about 5 to 6,000' elevation.
The engine never four strokes, even wide open in first gear or even in neutral at full throttle. It just screams.
So, since I've not had a two stroke in many years, my thought is to go to about a 140 main and maybe still move the clip on the needle to the fourth slot down.
If the 130 main is not considered too lean at this elevation I can still set the needle higher, to slot 4 or 5.
Advice appreciated from you folks more familiar with the KDX200 than I am. L. D.
It was dripping gas rapidly out the overflow so I took the carb apart, inspected the inlet needle and seat. The needle looked good, the seat looked like it might have some old gum from fuel on it. I made a small ball of very fine steel wool and cleaned the seat by turning the wool with a screwdriver.
The float was way low, about 22mm or more, he probably did that trying to stop the fuel overflow. The needle clip was in the top groove, again I expect an attempt to stop the overly rich condition caused by the too full float bowl. The idle mix screw was 1/2 turn out.
The carb has a R1172N needle, 50 pilot, 130 main. Airbox is stock. Mix is 40:1 dino oil.
The pipe is an FMF Gold Series Fatty with a Turbine Core muffler.
I set the float to 16mm, moved the clip to the 3rd groove, set the idle mix screw to two turns out.
The carb does not overflow now at all.
The bike has a lean spot as throttle is opened about 3/4 or full until it comes on the pipe. It doesn't stumble or blubber, just goes flat with poor acceleration. If I pull the enricher out the flat spot goes away while of course it is rich at lower speeds. With the enricher out it pulls smoothly right on up to on the pipe.
It pulls hard at lower rpms and hard after getting on the pipe with the enricher off.
I live and am riding at 9,300' elevation but the 130 main seems too lean to me, can't imagine who put it in there as the bike came from about 5 to 6,000' elevation.
The engine never four strokes, even wide open in first gear or even in neutral at full throttle. It just screams.
So, since I've not had a two stroke in many years, my thought is to go to about a 140 main and maybe still move the clip on the needle to the fourth slot down.
If the 130 main is not considered too lean at this elevation I can still set the needle higher, to slot 4 or 5.
Advice appreciated from you folks more familiar with the KDX200 than I am. L. D.