1986 Husky 430 AE Slipping in First Gear

I just bought a 1986 Husky 430 AE with a new first gear, stator, flywheel and I have a new piston in case it ever needs it. The bike was running sort of, needed adjustment. Got it going, idling properly so I can put it in drive. It starts out fine, until you hit about 15km/h then the engine revs up (If you leave your hand on the throttle) and you start slowing down. I have tried tying the lever in drive as far as it will go to see if it was just slipping the lever out but it does not seem to be the case. Any thought on what is causing this? Also it does not have the correct oil in it currently, it has some stuff someone at Esso said was the right weight, but I am not planning on leaving it in there. Could the wrong oil cause this?

Could you elaborate on this "new first gear" Which shaft is this gear on? Do you mean it got a new first gear clutch kit? The logic of folks buying these things without a source of first gear kits escapaes me. Thse kits which I seemed to need after five events or so consisted when available of three centrifugal shoes, three springs and one drum with six I believe bolts and locking nuts. It sort of sounds like second gear isn't engaging but the slow down part is contradictory to that theory. A centrifugal clutch grabs harder the faster it spins at least with all components working correctly.

Not sure oil would cause this problem. It does sound (as Fran...k. says) that second gear is not working, or at least not picking up the drive. Had the previous owner done any gearbox work ?? Sounds daft, but maybe they installed the sprag for 2nd the wrong way round !
Certainly worth pulling the cover and taking the mainshaft and auxillary out for a look. There could be bits missing or broken.

By new first gear I mean a new drum, pads, springs and I think a new center that mounts onto the shaft, one from a 500 with holes for 2 different types of springs, ones with hooked ends and one with a pig tail end. I also have a bunch of springs for it.

Also when it slows down, it slows down until first gear grabs again so if it slows down to 10km/h first gear grab again and it goes. Is second gear the problem then, not grabbing? I will have to check. The guy I bought it off of was happy enough to stay in contact and he has a first gear puller. Will I need that to get into it? I have owned it for a few days so I really haven't had time to dig into it really and don't know what I will need.

If it were me I would be pulling the cover off before I even thought of running it again.
You may be able to see what is amiss without removing the 1st clutch, but you won't be able to fix it. Check for broken springs on 2nd gear, and then check to see if the sprag clutches are working correctly. Also check the drive engagement. Although they are much better on later models, they can still wear.
Post up some pictures as you go.

You need to pull the center for the first gear shoes in order to get the forward shaft out of the transmission, that is the one with second and third gear clutches. The shaft with the freewheels or sprag or one way devices comes out via a plate at the sprocket for the chain.

The way I think it works is that none of the gear engagements ever drop out (up shift mode) just the next higher one comes along and spins the assembly faster hence the lower one free wheels or coasts. This also why it doesn't coast in high or third gear.

Yeah, I don‘t plan on running it again until I have fixed the problem. I had bought it running but not driving as it was idling too high too engage the transmission, I only drove it this time because I had got the idle adjusted , didn‘t know something ws wrong with the trans. I am out of town currently, but this weekend when I get back I am planning on taking the engine right out to work on. Would rebuilding the entire thing be a good idea? I wanted to paint the frame with plasti-dip so the engine has to come out anyway.

Hmm ... last time I just pulled an engine just to do the bottom end I ended up restoring the whole thing ! Couldn't help myself ......
That was the old KLX250 twin shock. Worth it in the end.

It is about a auto military 250, but it can help.
Some parts are different of yours.
http://www.teamnorrland.se/Renovera AE.htm
The 86-88 430 ae workshop.
http://www.yourhusky.com/files/86-88-Auto-shop-manual.pdf

That would be me in the end as well. I could never work as a mechanic as a job. I have a hard time going in and just fixing whats wrong without cleaning and tidying everything else up.

I was playing with the idea of 3D scans for the first gear drum and shoes and the left side cover that gets eaten when the springs go; parts that wear out faster. Having a computer file that can be editted on a flash drive for them and having a shop with a Computer Controlled CNC mill just cutting a bunch out as needed rather then having to try and buy them. Exact copies, as many as you want as you need them.

Thank you for all the links! Those will help a ton! Much appreciated!

ive never owned an auto but its clear that you must get it right inside or else big $$trouble awaits.
As the bikes are simple (Huskys in general), you might as well give it a good freshen up as they are well worth doing... that way you get a good run out of them before further work is required. I rebuilt my 400 three years ago and have had 3 years trouble free motoring. its comfortable to take it out on long rides knowing its ship shape inside....go for it

Have raced my 500 auto for three seasons at least and never had any trouble with the first gear clutch. I can't measure any detectable wear yet compared to a brand new kit. I only use it for VMX - wouldn't trust it on a long enduro loop!

I followed a couple of autos around the Harrow track yesterday and they were picture of mechanical elegance ( and hard to pass!)

Found the problem. Was going to post pictures of the entire trans (currently apart) but I happened to notice the problem. The shifter inside the case is worn down, it has 2 little "towers" that push the engagement gear back and forth to engage/disengage the transmission, and the tower on one side is worn down so the engagement gear can slide past. I guess when the bike gets going fast enough the gear slips out into nuetral without moving the shift lever. The engagement gear looks ok though. On the side where it can slip out the corners on the gear show a little wear (Probably from wearing the tower down) but not enough to be of any concern or require replacement (the wear is very minimal). I feel pretty lucky. I now have to go look for that part, knowing my luck it will be impossible to find! Haha!