1999 KX250 gear shifting issues ?

[swordcombat]

Hey all , I have what I would consider a strange issue
With my 1999 KX250 shifting.
Now the engine has been fully rebuild with new bearings
Seals and every clip replaced aswell as Wossner and  new clutch basket
And EBC dirt rider clutch.
Now the bike is on stand half built and
Not running yet.
So when I try and shift into first there is nothing there
But when I shift into first whilst moving primary drive it shifts into first?
But without using the primary drive it shifts up through all the gears.
Now the shifting forks and drums were all inspected and were fine.
Does this mean I need to take the whole engine apart and what could be the issue?
As I would like to do this before I put any oil and coolant in it.

[umberto]

Does it go into first and stay in first?  Does it upshift normally from there, or do you need to keep moving the sprocket?

[swordcombat]

No! Basically you move the sprocket it goes into gear
Then you move it some more and it then clicks likes it's in gear.
It then lets you shift up and turn the sprocket a little and then goes into gear
Because the sprocket stops moving and so on.

[swordcombat]

Also yes it stay in first and then let's me go into
Neutral and then I have to move the sprocket to
Go through the other gears

[umberto]

If it shifts smoothly with no extra effort and stays in gear, I think you are fine. A couple of the bikes I've owned are like that where you have to turn the sprocket to get them to change gears. It's never an issue when riding, just when sitting on a stand.

[swordcombat]

right so after messing about I realised I was doing things wrong.
I was moving the sprocket then stopping and changing gear.
But with the sprocket continously moving it went
Through all the gears and stayed in all the gears.
So does this mean all is ok and I don't have to strip apart
My freshly built engine ?