Still battling tuning this FCR Carb, need some other folks knowledge
Finally got to the track with the quad to really try and tune this thing and I am not sure if it’s jetting or if I am having other problems.
I will start with mods/build. 05 with fresh build. OEM crank, CP piston 13.5.1 compression and web cam (grind # 961-962). It has a 06+ FCR Carb. NCVQ needle with the clip set at 3rd notch down. 52 pilot jet, 160 main jet and 55 leak jet. Also has CRF ignition, flywheel and stator installed on it. The valves I am not sure as the work was already done when I bought it. It looks like it might have mild port work. I have attached a photo looking into the intake side of the head so you can see what you think in regards to port work.
So originally I was having a start issue. This has been corrected by cleaning the carb and installing all new gaskets in it.
Now, onto the current issues. Finally got to take it to the track and really run it. Several things I observed and/or happened.
First, it seemed to run pretty good other than sometimes it would bog for a quick second when I would get back on the throttle as I was getting ready to land from a jump. I thought maybe the pilot was too big so I dropped it down to a 48. After installing the 48 pilot it still was still doing the same thing but after a few laps it started bogging more and ended up shutting off on me. It took it a few minutes before I could get it to fire back up, when it did I just went back to my truck where my tools were.
I was revving it in neutral and listening to the exhaust. When I would really rev it, it was popping and would shoot out a flame on decel. So I thought maybe I needed to adjust my fuel screw. It was set at 2 turns out so I turned it out to 4 and slowly started going back in. I only went half a turn and the idle picked up. So I backed it off a 1/4 of a turn and did some revs in neutral again. This time no flames and it sounded a lot better. Since I was out beyond 3 turns on the fuel screw I thought well I need to bump up my pilot jet. So I put a 52 in it but then when I was doing the adjustment with the fuel screw I couldn’t find a spot where the idle would pick up. I started 4 turns out and slowly kept going in until it was the whole way in. So I set it at 2 turns out and figured I would give it a try. Went back out and still the same thing, intermittent bogging and it eventually shut off on me.
Next I tried bumping the main up to a 170 and I took it for a ride down the road on pavement so I could really just run it through the gears and rev it out. It accelerated great but when I would let off the throttle and start coasting it would pop real loud and carry on. Even shut off at times but if you pulled the clutch in and let it back out it would bump start right back up.
I have read the thread on the FCR carb and also the thread on jetting but I need some suggestions as I am really striking out.
Do you think that this is a jetting issue? Or do I maybe have a two things going on here, jetting and something electrical?
Any help is appreciated, sorry for the long post. Just trying to give you as much information as possible.