. Facebook marketplace $1200 buy. It's a project bike. Not looking for super crazy racing magic, just overall reliability for general fun and ease of use. Carb, battery, tires, fluids and we should be at least running. So, we shall see. 
I’d recommend a Keihin 36mm PWK if you’re a slower, technical terrain guy, or a 38mm if you ride faster stuff. Get it from JD jetting. Best 2 stroke carb on the planet. Also, don’t ever sell your 2019!!!
If you don’t want to deal with rebuilding the carb, send it to JD Jetting or Tokyomods.
My bike has no carb at all. Was looking for a plug/play solution. I'm mechanically inclined, but choose not to go with stadard/FCR carb.
I was lucky enough to pick up 2019 Husqvarna TX300 about 6 months ago that only had 8 hours on it, which is the last year for the carb on TX and XC line.
If whoever you bought the bike from didn’t know how to adjust a carb make sure you check the top end and valves. The valves on Yamaha 450s wear tight and make for hard cold starts.Yeah, for me, I chose this because my Wr450f doesn't have a carb due to the previous owner breaking/damaging it while cleaning/tuning/replacing jets/whatever
My other bike is 2013 BMW G650GS that putters around just fine and dandy. Got some plans for that one too. Stay tuned
This right here. The titanium intake valves that are in common use in these hyper power 450s constantly rise in the head due to valve face wear into the seats. I once had a KTM 450 that went to just about zero intake valve clearance 3 times during my ownership. A common trait when intake valve clearance wasn't enough was extended crank/hard starting. I converted over to the 300 2-stroke after that and never looked back. I'd rather do a 2-stroke top end every 100 hours vs pulling cams on a 4 stroke to change out valve shims every 15-20 hours.
The valves were definitely an issue on the early MX 4 strokes, but they don’t really have that issue anymore, unless you’re riding a 250f and bouncing it off the rev limiter for its whole life… or not keeping the air filter clean.
I haven’t personally battled the KTM jetting but there is a 31 page/900 reply thread on Vital specifically for the carb settings. When people in mass are trying Kawasaki slides/Yamaha needles/Stic blocks etc. there is definitely an issue. It literally created its own little aftermarket. I’ve ridden 125 and 250 2-strokes from 97 and still do today and never thought of drastic carb swaps.
Neat. There’s also 900 page jetting spec threads for every other 2 stroke out there too. You’re dealing with people who didn’t trust the manufacturer oil ratio of 60:1, which is what the jetting specs were built around for the 2017+ 250/300 engines. This has an effect on overall jetting. So you can’t mix 32:1 or 40:1 and run the same jetting specs meant for 60:1 and expect it to run the same. There’s probably 10 MXA articles pointing to this as well with their test bikes. This is what a lot of people are doing, because many can’t let go of running 32:1 in our bikes when we were kids. Oils have come a long way since then. Again, you’re also dealing with people who don’t know how to jet, don’t understand what each jet effects, and don’t want to take the time to learn/test. The easy button is to take to the internet and let someone else figure it out. Kind of like lazy people do with reloading… You also have to remember that the manufacturer is going to give you richer than needed specs so you don’t burn up your motor. You can thank the lawyers for that.
Interesting that you mention a few swipes with a triangle file on the slide. I have been reading 100s of forum pages detailing the Graham Jarvis mechanic's mod for the Mikuni TMX carbs. It seems that making the slide cutaway larger at the bottom center of the slide creates a stronger airflow signal around the pilot circuits. A lot of folks have reported that this mod virtually eliminated the stutter from idle to 1/8 throttle. I'm getting ready to do it to the Mikuni on my 2019 300XC along with the JD Jetting kit.
Yep, there are a lot of people that have issues tuning a carb. Either they don’t want to hassle with it or simply inept or whatever the reason, that’s where the Lectron and Smart Carb become attractive. I immediately went to a Lectron due to gas mileage and our big elevation changes during a ride, but I’ve got to be honest, I didn’t give the Mikuni a chance.
It makes a big difference. I love free mods.
