500 Two-Stroke Tech

cidair wrote:Still OEM needles....

Ok
That will have an effect. The org needles are to rich in the midrange (4-5k rew).
When you open up thr intakeside it will be even more noticable.

I changed the needles just to be sure when I went for UNI-filters on the elephantears.
No stumble in the midrange but at low rews/ low throttleopening it was not fun to ride in traffic.
That made me rejett the carbs by input from here.

I discovered that at idle the bike was wery rich at tickover (was trying to balance the carbs) and my plugs went wet.
That´s why I changed the pilot air jet to 1,4 size to lean the mixture at idle.
That affected the next circuit so I had to go bigger on the pilot jets. Had org size 22,5 (or 25) and changed up to 27,5 but still wasn't enough.
Had to put in 30 size and then it worked fine.

The mains has been untouched.

As is now I can abrupt open the throttle at almost tickover and the bike will pull without any hesitation all the way to redline and more.

Good luck with your rejetting // Jeppe

Long time since last post.
Still working on to get the 5k-7k to work properly. It just stumbles when I open the throttle. Have Jolly pipes and open air filters.
Changed to #1.4 pilot air jet, #30 pilot jet. Have #210 main jets.
Now it also hesitates when I open up the throttle fully at around 8.5-9k....

I have #250 in the garage. Maybe try these? I'm getting more and more confused about this, the more effort I try to put in to solve the problem......

#250 main jets mounted. Much much better response. Just that last 5% missing.
Will check the position of the needles now.

#250 doesn´t seem to be enough. Will try #300 as next step.