450 Sx

[munch]

Any 450 SX ride reports ?

 

[TMXrider]

Just got mine out for the first time yesterday. Feels light and fast, but got quite a bit of popping and backfiring when I let off the throttle. Not as much low end as I thought. Seems like all power is in mid-range. Possibly, I need to change jetting. Any suggestions?


TMXrider

 

[Shaw520]

TMX, The popping on decel is an indication that at least the pilot curcuit is lean, I would go larger on the pilot, If its popping on top end with throttle open, that is indicating the main is very lean,  it cant hurt to go a bit larger on the main, or raise the needle a couple notches. Let us know how you make out.

 

[munch]

I've been considering an sx for some motocross, but probably more harescrambles, Like the light weight but i'm worried about the 4 spd.
I understand that it can be converted to a 6spd relatively cheap.
Any input would help

Thanks

 

[flynbryan]

munch I think it'd be alot easier/less expensive to buy the 450exc. Plus you get the trip metter, a light, and six gears(stock). Just ignore them when they laugh at you for having a headlight on an mx track. I think it was motocross mag. that pretty much chewed up and spat out the 450sx. Under powered, soft forks, and big gaps between gears. I would stick to people that have ridden the bike though it seem that all the mags like to bust KTM's balls. Back to the subject I would go w/the EXC models if you can find one. The six speed would be much more beneficial if they offer it.

 

[dstktmusa]

Here is the jetting that works the best in MY 450SX try it and deceide for yourself.

42p
OCEMN in the 2nd clip position
160m.j.
1.0 turns out on the fuel screw.

No popping on decell and much improved MPG's. Rev's VERY quick and you can whack the throttle open at very low RPM's.

 

[emoney]

Is the OCEMN needle only available through the dealer. I usually get my Kehin parts from SUDCO, but they don't carry that needle in their catalog.

 

[Shaw520]

Sudco carries the EMN, give em' a call.

 

[TMXrider]

Thanks for the re-jetting info. Will let you know what works the best.

 

[emoney]

Timing chain on my 450SX broke after about 1.5 hours on the bike. Still trying to sort out where and why it broke. Side cover bolts were loose on both sides and there was some grainy sludge that came out of the radiators and water jackets. Will post more info later as we tear into the motor.