Why is there a plastic tie around the carb and the side stiffener? More below...
But first!
Bobby Watson: Thanks! You're tip on adjusting the LSN really helped me a lot today.
If you've been having a "run on" problem when going off-throttle (i.e. the idle doesn't come down right away or doesn't come down at all), it may be an idle screw problem, not a HSN/LSN problem like you might think. Try turning your idle screw two turns counterclockwise (or more if that doesn't work) and see if your "run on" problem doesn't go away. You should be able to see the difference on the starter box when you blip the throttle - the idle should drop immediately. You know you've gone too far if the engine loads up and dies after 15-20 seconds. If adjusting your idle screw doesn't solve your problem, it may actually be your HSN/LSN.
The engine ran great with the new inlet and button head today. I didn't really have a problem putting the filter on (I use GQ) and per the CNC button head instructions, I used 0.3mm shims. Used 30% O'Donnell fuel and a CRF 7 plug. I could have used a 6 plug for more power, but the 7 was more than fast enough today for a first time run with the new parts. I will try a 6 plug the next time I race.
Now for the plastic tie (aka "the fun part"
)
I replaced the carb insulator AND the retaining screw assembly and the new carb still rotated on me. On the MTX-4, the carb's rotation positioned it right on the brake disc - and the brake disc was so unhappy about the situation, it started to grind the carb body and the spray nozzle screw head. Cool, huh?!! Imagine having a drag brake all the time! Needless to say, I was P.O! The first time it happened, I was in the middle of a qualifier. After the qualifier, I had to yank the engine (a real bitch of a task on the MTX-4) and tightened down the retaining screw. Well, that didn't help and the carb rotated again at the end of the second qualifier, but since the carb was already ground down a bit, it wasn't so bad and I was able to finish the heat.
So here I am, in between the qualifiers and the mains asking myself, "How am I going to prevent the carb from rotating? Obviously, the retaining screw is not holding the carb." That's when I came up with the idea to use the plastic tie. Certainly not the best course of action, but it prevented the carb from rotating and I did end up placing first in my Main.
Never had problems like this with the original carb.
Anybody else having problems like this?