125-200cc Struggling to find 1st gear

My husqvarna wr125 has started to play up when trying to select 1st gear.

It hasnt been run for a few weeks but when i fired it up it seemed to have a little grind as i went into gear, i thought the oil may just need warming up, but after riding for a little while it just seemed to get worse.

I did change the gear oil after my last ride.
I followed the manual which said 800ml but then i took out the bolt on the side for checking the level and about half of it came straight back out.

Have i done something wrong? Im thinking i should have maybe put the bike in gear and given the box chance to spin up and let the oil settle first... every other gear is fine and crisp at changing its just 1st Hope ive not shafted it!

Can anyone shed any light on what this might be?

I topped up the oil last night and its the same. It seems to find first easier when its rolling but can sometimes jump into neutral from 2nd, could it be a clutch issue or is it more likely to be the gear itself? or syncro (if this has one?!). Or even gear selector? I don't really know how it all works too well

It sounds like a clutch dragging issue to me. Did you change the kind of oil you were using? Have you inspected the clutch plates, basket and hub lately? There could be some notching going on.

Thanks, yes i changed the oil to motul 2 stroke synthetic oil recommended by my husky dealer. Im not sure what was in there before as ive not had the bike long and that was my first oil change.

I have noticed when you go into gear with the clutch lever pulled in the bike feels like it wants to pull away slightly, and adjusting the cable hasnt changed this, so i will have the clutch off and see if thats where the problem lies. Thanks

Clutch seems to be working ok so i don't think its that.

Has anyone done a guide on looking into the transmission?
Is there anything i can do without having to split the crankcase.

Ive noticed that the problem is dropping down into 1st from neutral. If i start the bike in neutral, go up into 2nd then back down it will engage 1st gear fine?

Could it just be the selector?

On my WR250 I had problems getting into second, and it kept popping into neutral. Your problem seems slightly different, but in my case there was a loose part in the shift mechanism. I took the clutch cover off, took the basket out, and behind a little plate there was a shaft with an allen head that was finger loose. I took it out, cleaned the threads, red loctited it, and haven't had a problem since. I've seen a few others online with the same problem. However, like I said, your problem sounds slightly different. May still be worth a try though if you don't find anything else.

Thanks for the advice mate, it looks like i need to take my gear selector shaft out as the teeth are worn on the outside. I will take the clutch and basket out first tho and see if theres anything i can spot

IIRC the part to look at is the shaft the star gear rotates on. You have to take a small plate off to get to it. I hope that's it because it's an easy fix.