Just finished my first engine rebuild on my 2001 SUV 1200 that I got for free with an almost blown motor. Actually went quite well. Finally blew about five weeks back, just finished rebuilding it last Thursday. Aside from engine I also rebuilt the carb although the parts I chose probably wasn't my best choice. It was $94 and the seller was 100% feedback on ebay. I would post a link but cant. I only found out that OEM kits are best just recently.
About carburetor: Mikuni SBN series.
At first it would never start, unless I dripped fuel down carb neck. Then after correcting the mistake I made, engine was receiving way to much oil premix (guide says 3oZ per gallon, but that seems like a lot and I didn't rebuild my crank so shouldn't really need premix), after draining gas and adding fresh non premix engine ran decent (more details below). Took carbs out and realized two things 1) One needle was missing the clip that goes around lift arm and 2) accidentally did pop off pressure according to lift arm color. (oops). The current carburetor config is using all stock jets, seat is 1.2 (probably my first issue eh?), H and L screws set to stock, and the correct pop off pressure it set at 47 psi.
The new rebuilt top-end has a 1.5 overbore (adjusting carb H and L screws didn't really fix issue), has new head as well as gaskets. M cylinder (front) has 100 psi, C has 98, and PTO has 100, seems pretty damn healthy to me
Reeds are in good condition still, no light passing through and they snap back into place instantly.
Issue im facing more in depth:
Okay, so the jet ski idles great in and out of water. When out of water I can rev it pretty high, but am afraid of going full tilt with no cooling. When in the water I can build a tiny amount of speed around 10mph then anymore throttle and it drops RPM and cant rev past 2/8 throttle. When I had the premix in I tried my best to tune the high and low of carb with no success and when the time came to put new fuel in with no oil it was getting dark, and didn't have time to tune. Still, it struggled to accelerate. Looking at my spark plugs they seem to signify good engine operation. So yes, it still could need just a little tuning especially because of overbore, but I would appreciate any other ideas evolving around this issue. This is my first ever carbureted two stroke engine that ive owned and worked on so I'm a little lost. I guess while I wait for the next weekend to go to the lake I'd like to hear what y'all have to say. Thanks!