Bump
Race Dog
Been "playing" again and swapped out the old CV carb on my KLR600 for a Mikuni VM38 round slide.
The Idea behind the carb swap is not for more HP but to get a throttle that gives better response when you twist the grip.
Unfortunately the KLR is not really a great candidate for a pumper carb as there is very little clearance to squeeze a flat slide let alone a pumper carb into the frame.
I am using some info I found on the net for a VM38 swap into a KLR650 and have taking his jetting specs as a starting point
But know very little about these types of carbs.
After installing the carb the bike started fine, let her warm up and set the air screw and idle.
On the first test ride the bike would pull cleanly from idle all the way to ~ 3/4 throttle and then bog down and blubber.
Roll the throttle off slightly and she would pull again.
This would suggest to me a over rich condition on the main / needle at the upper end of the throttle range.
Pulled the slide and dropped the needle by lifting the clip up one slot (now in slot 1 = top / leanest)
Test ride... she pulls through to ~3/4 throttle just fine but now just runs out of power. Rolling off the throttle does not have any effect in improving the situation.
This would appear to me as a lean condition?
Now I understand that up above 3/4 throttle the needle has less of an effect and the main jet is the major role player here so a couple of questions for the carb jetting Boffs....
1/ The needle has 5 slots. With the Clip now on it's leanest this has now leaned out not just the upper end but also the entire 1/8 to 3/4 throttle range.... am I correct in my thinking here?
2/ What would be the "best" clip position to start out at while playing with main jet sizes to get the full throttle fueling right and then adjust the needle clip to lean or richen the 1/8 to 3/4 throttle.... I am thinking center clip (3)?
Thanks
W
The Idea behind the carb swap is not for more HP but to get a throttle that gives better response when you twist the grip.
Unfortunately the KLR is not really a great candidate for a pumper carb as there is very little clearance to squeeze a flat slide let alone a pumper carb into the frame.
I am using some info I found on the net for a VM38 swap into a KLR650 and have taking his jetting specs as a starting point
But know very little about these types of carbs.
After installing the carb the bike started fine, let her warm up and set the air screw and idle.
On the first test ride the bike would pull cleanly from idle all the way to ~ 3/4 throttle and then bog down and blubber.
Roll the throttle off slightly and she would pull again.
This would suggest to me a over rich condition on the main / needle at the upper end of the throttle range.
Pulled the slide and dropped the needle by lifting the clip up one slot (now in slot 1 = top / leanest)
Test ride... she pulls through to ~3/4 throttle just fine but now just runs out of power. Rolling off the throttle does not have any effect in improving the situation.
This would appear to me as a lean condition?
Now I understand that up above 3/4 throttle the needle has less of an effect and the main jet is the major role player here so a couple of questions for the carb jetting Boffs....
1/ The needle has 5 slots. With the Clip now on it's leanest this has now leaned out not just the upper end but also the entire 1/8 to 3/4 throttle range.... am I correct in my thinking here?
2/ What would be the "best" clip position to start out at while playing with main jet sizes to get the full throttle fueling right and then adjust the needle clip to lean or richen the 1/8 to 3/4 throttle.... I am thinking center clip (3)?
Thanks
W
