07 KTM450 exc - few issues, any help is appreciated.

Hey, checking to see if anyone has had any or all of these issues. 2007 KTM450exc...an easy 29 hours, 950kms, not raced. ridden for fun. valve adjustment done at 15 hours. regular oil and filter changes. exhaust cut mod done, emission crap removed, JD jet kit installed. Bike has gotten progressively worse the last 8-10 hours (200kms) or so.

1. overheats like a b*stard....last Sunday, 10 degrees, slow to medium trail riding with my 7 year old...had to stop twice while it boiled over. Flushed the rad before we went and put Engine Ice in, still overheats? Fan is an option I realize but 10 degrees and no load and still over heating on what is arguably the best trail bike?

2. bike will only run with the fuel petcock in the reserve position. I've removed the petcock, cleaned it (wasn't dirty), no idea?

3. bike runs rough at low speeds. when full throttle banging through the gears no issues pulls like a train. anything trail speed and below its like riding an 78 Kawi 2-stroke, constant revving to keep it running, sputters then takes off...almost pitched me over the bars a couple times when its dies out mid throttle while standing going through the woods.

Of course the dealership says bring it in but I'm handy and not afraid so I'll try things on my own first but I don't just want to start throwing cash into it. Any input is appreciated. Thanks,

Might need to re jet because of colder weather.

Check advrider.com, odsc.on.ca, and thumpertalk.com.

check the rfs section on ktmtalk.com,

I'd probably start by checking the spark plug, and plug wire.
jetting must be off or clean inspect carb, did you bleed the air out of cooling system?
shouldn't need a fan, mines a 05' exc and never boils over on me.

gas cap vent?

Sounds like a significant fuel delivery problem. If it is running really lean at part throttle, it explains the dodgy throttle response and hot engine. Full throttle obviously seems fine. I'd take the carb apart and make sure everything is clean.

I know a few others with the same model, with the same problem. Basically they've been told that they have a race bike and it should be ridden like that, and not for leisurely slow rides.

not exactly a race bike by race bike standards, longer stroke, heavier crank, diferent cdi, lower compression.
should be able to ride at a tame pace no problem, but..
don't let it idle, need air flow past rad, stopping for a min, shut off, e-start nice.
don't over fill radiator (unless using a catch return tank) just over fins inside is fine.
jetting needs to be setup right, lean from factory

sounds like either carb is pluged up (pilot jet) (fuel screw)
or valve adjust at wrong tdc,

I must of got lucky, bought my 05' used, no fueling problems or over heating. but riding on street lately SM.