DT125 Main Jet Troubleshooting

[darkangel]

Does anyone know the recommended main jet size for a de restricted DT?

I am having all sorts of problems getting the jetted sorted out.

The stock jet for my bike (year 2000) is a 240 mikuni jet
Basically with that jet full throttle does not rev out, it will refuse to go past 9k and make no power if it does.

I Richened the needle and changed to a 260, mid range improved, no noticeable difference to WOT good or bad.

With the 260 in i then went for a ride without the airbox cover on, at small throttle positions it went like mad, actually going upto redline and making power past 9k, it made the difference of 10mph each gear.

However twisting the throttle past 1/4 made a boowaaang noise which i am quite sure shows it being lean, needless to say it did not run well past 1/4 throttle and twisting the throttle slowed the bike down.

So then i went for a few rides each time restricting the airflow (from completely open airbox) but i just cant get WOT to rev out, 3/4 throttle onwards makes less power then just sitting at 3/4.

Do i really need to upjet further? to a 270 or 280? it seems allot for a small engine