Mikuni off an '82 WR250

Hi there, I've searched this great site but cant find what the 'basic' settings/jet sizes etc are for the above bike, it is a 38mm yes? When I re-assemble the carb I would like to configure for a temperate climate for starters and work from there.
Also, anyone have an IPC for this carb? Thanks again, much appreciated!!

1982 wr 250 carb setup or starting specs.

Mikuni 38mm

Main jet #410
Needle jet # Q4
Idle jet #45
Needle position #4 slot
Needle 6 DH 16
Air screw 1 1/2 turns from bottom
Throttle slide 2.0

This is a starting point depending on your mix ratio and altitude. The orginal mix ratio was 20:1 castor oil.

The premix ratio is not relevant, the difference between 20:1 and 100:1 is so tiny it will have no impact on jetting. The formulation of today's fuel though is very different from the fuel when those specs were used so expect that to be a starting point.

20:1 isn't like 40:1. 20:1 is more oil less gas. 40:1 is less oil to more gas. We reject to the ratio of gas to oil.

I had a box of seezed pistons because I was using the wrong ratio and 2t oil. In the beginning decades ago.

One of my coworkers runs 16:1 in his 88 Honda cr250 he raced it and beats the snots out of that bike. It's still orginal. The riders style matters.

My son on his Honda 125cr I built in the beginning, I leak down tested it over night it held crankcase pressure. I bored it, ported it, I ran 40:1 ratio super M maxima. High test gas. My son rides very hard. This bike was beating the 250's. But seeking pistons every so often. It lasted longer with jetting. But I think there wasn't enough oil for his style of riding. The kid takes no prisoners. He's full on. Funny he does great practicing. But chokes on race day he gets intimidated. I coach him not too.

I found an engineering error on my sons KDX220 transmission. The input shaft opposite the clutch there's a needle bearing that's covered by a larger diameter flat washer. We blew the needle bearing twice. I ended up grooving the case so oil can flow behind the thrust washer into the bearing as the shaft turns. I did spiral grooves. I contacted Kawasaki engineering since I worked for a engineering group in the states here it opened the door for them to talk with me. They said they never had a problem. Again my son rides hard. Any weak link will show up.

Note, the best bike he ever rode was my 83/430wr he couldn't hurt that bike.

this post has NOTHING to do with anything the guy is asking.
not sure why you keep saying everyone here runs the wrong oil ratio, when alot of our bikes last with hours on them.....why do you keep saying 20:1 when if you do check the manual it states 4%? simple math says thats 25:1..
sometimes the manual even states "3-5% depending on oil"

for 82 250 wr, the manual states "use oil manufacturers recommendations"

false information...myths...oil ratio has so little to do with jetting..

Bill, when it comes to jetting the difference between 20:1 and 40:1 or even 100:1 is infinitesimal. It's there but it's insignificant especially when compared to other factors like altitude, temperature and the chemical traits of the fuel like specific gravity. Oil ratio is absolutely irrelevant to jetting.