Hello! I have an 04 TC450 with the TMR41 carb on it. I'm well aware of the reputation these carbs have received mounted on this particular bike. Anyways, the bike is new to me and I figured I'd form my own opinions about the carb as for whatever reason, they seem to hold high regard in other applications. Go figure. So, the bike hauls absolutely righteous ass as it is. Starts super easy and wheelies everywhere. It did however pop on decel with the Leo Vince muffler on it and felt lean off idle. So I put a pilot one size bigger in and have the pilot screw turned 3 full turns out (could have perhaps gone two sizes bigger). That fixed the popping on decel and the slight surging off idle (it also made it idle smoother). The issue I noticed now that the pilot circuit is sorted is that if you whack on the throttle from idle, it sometimes pops and dies. My guess is that the accelerator pump is timed too early and it floods the girl now that the pilot circuit is tuned. Before, when it was lean. it didn't have the problem. Now It runs nicely through the rpm range. Plenty of low end grunt and smooth all the way up to the top. If I can fix the throttle whack stall I'll be quite happy for now. Only time I ever uses throttle whacks when riding are when there are logs on the trail. You chop the throttle to get a little weight transfer and then whack it open to lift the front end (saves the clutch) I was just wondering if anyone had any experience with adjusting the accelerator pump timing. I did a search and didn't find anything. Once I get this sorted I believe the carb will run spot on. main jet and needle height are stock position.
Well, did some google search and found that tuning to remove popping is actually backwards. Popping on decel is quite possible on even a perfectly tuned motor. So, tune for performance and not to remove popping on decel. I did two things. Put the idle mixture screw at 1 3/4 turns out. Yes, it still pops on decel here, but very little. Here the idle is the highest and smoothest spot, and it doesn't pop and stall no matter how hard or often I chop/whack the throttle. I also adjusted the accel pump linkage as far out as it goes so the pump action is delayed. This makes the bikes start super easy, idles great, has nice throttle modulation and absolutely hauls ass with no flat spots. Hope this helps someone.
