Unless the ignition is way off backfiring is usually a sign of a lean condition , if it is running lean it won't make full power.
The 32T raider - Waveventure engine is something I have a lot of time tuning for different setups.
Running lean would also explain your bogging condition , are the low speed screws really only 1 1/4 turn out from fully seated ?
Stock settings are at 5/8 a turn which is way too lean , they will barely start up without running the battery down at those settings .
I usually set those at about 1 turn to 1 1/4 turns from the factory settings then those engines actually crank up without the choke and run well especially out of the hole , how hard is the ski to crank , do you have to use a primer to start it , if so again for that particular engine too lean.
That stock 701 61X pipe is most likely not going to run that well with your particular engine, it needs something that breathes much better, even the stock 62T pipe has way less restriction and better scavenging than the stock 61X exhaust system does , you are choking that engine way down by running that pipe. what you have is kinda like sticking a small pin in an X2 with the 650 pipe and manifold , way less than optimal performance guaranteed.
I can't give you good jetting instructions for that setup but set the low speeds at 2 turns out and see how it starts and runs, if that's too much go in 1/8 a turn at a time till it pulls off the bottom cleanly , at those low speed settings you will have to readjust the idle speed up some to get it to idle, try it, what have you got to lose ?
