O9 450 X rough at low revs

[raoulduke]

Just got a brand new 450X. Love the bike except that at low revs it runs terribly. Very hard to set a constant idle speed, you seem to get it right then run it for a bit and it's too high or so low that it stalls out all the time at low speeds. I was looking to keep the bike standard, don't need more power, but will I have to jet and do air box mods just to sort this out?? Thanks.

[FORMA MOTO]

4-Strokes with slipper pistons don't like to be lugged, so you should take care there. Partial throttle is ok, but go up in rpm's for more torque, rather than opening the throttle more.

Jetting is critical to a smooth running motor. A very lean engine will not settle down to a smooth idle.

Read the 'stickys' at the top of the forum to find out what others have done successfully.

[Justin Hambleton]

will I have to jet just to sort this out?

Yes. Always. Any bike needs to be jetted properly. Stock, the 450X is dangerously lean, although I don't know how they come in Portugal (assuming that is where you are located).

[raoulduke]

The bike is standard UK spec. A bit dissapointed to have to re-jet immediately on a 'competition' machine to get it running right. Mid range and top end are great but when it gets slow and technical this low end fuelling is a pain in the a**. Will get reading the stickies and get the jets out i suppose...

[HRPFNSTF]

I'm having the same issues with a new 09. Hoping you'll post your results, since I'm also hoping to keep things mostly stock and simple and not get sucked into Major Modification Hades.

I have read on this forum, and heard personally from one owner, that it may be as simple as going up on the main to 165 and changing the needle to NCVS, but I'm still stock (with JB Weld smog block off completed), so don't take that for gospel!