Any old timers or older husky riders here with the husky knowledge?

I always say never take a cylinder bore for granted till we measure it. Refresh, My as advertised husky 250 cylinder that I thought was a 390cc bore that I purchased turns out to be a 420cc bore. My saga for the 390 build continues on.
I know the cylinder is from an automatic 420. It has the same transfer ports as the last of the 390 cases. It can be ported so the older transfer ports will work on the newer husky cases.
I'm gathering my thoughts while I gather parts.

Did husky ever offer a six speed 420? Besides the auto 420? Was it common to put a 420 cylinder on a 390?

The other cylinder swap is the 86 400LC TO 430LC cylinder swap. I think in the early 80's like the air cooled 430 era there was a 500cc kit that was offered by husqvarna.

My problem is that once I port it to fit the newer husqvarna case it won't still fit the older 390 case/transfer ports. Plus I'm not sure how much to invest into spare cylinders/parts. I plan on working on huskys till my grave. But my son will carry the big H torch once I pass it to him. He loves the huskys like I do too.

I hope I'm not being a pain asking and researching for the 70's & 80's husqvarna knowledge. If so tell me I'll go away.

I find the newer early case where husqvarna put a 250cc to 500cc cylinders on to be bullet proof if the oil level was maintained and the gears didn't crystallized from over heating from no oil. The Swedes hit a home run on the design.

Ok older husky guys? Newer husky guys with knowledge? Any young husky guys?

I have a few 420 cylinders and they appear to be the same as the 430 air cooled with some shaved off the top and bottom, not all done the same way either. I do not have any Husqvarna 390 motorcycle stuff go from 360 to 420/430. (There is a current 390 husqvarna chainsaw with porting similar to a 430 l/c of this section in many ways) No standard shift 420, I think the difference ought really be more than 10 cc as they are both 86mm bore and 71 vs 74 on the stroke. The auto crank is narrower and far from full circle like the 430. My 360 has a crank similar to the 420 perhaps called pork chop shape. There is some stuff buried in the service bulletins on here in the reference section which seemed to me to take 390 and do something I thought became stock around the liquid cooled 430. I am pretty sure the later cases 82 or so hold larger bearings in some spots.

There is no kit to go from anything to a 500 as the stroke and crankshaft is significantly different. The cases are the same for the 400, 430, and 500. The 250 is essentially the same with smaller crank area. The auto cases are aluminum and I have been told they were sourced in a different manner than the magnesium two stroke standard shift ones.

There was a 500cc kit offered that came with the crank, piston, cylinder etc from husky to make the 430 a 500.

I guess I might go with a 430 crank and case for the 420 cylinder I need to install a 1.5mms spacer on the base gasket. This would also advance the port timing.

Perhaps you are talking about the 470 PC Kit.

http://www.cafehusky.com/threads/470-pro-circuit.36840/

We had a older husky dealer here and when the 500 were offered husky offered a 500 kit for the 430. It was cheaper than buying another bike.

The only 420 was the Auto, no manual bikes had the 420. It was not common to put a 420 cylinder on the 390 because it is nothing more than an '80 390 bored to the standard 430 bore, all you had to do was bore it to 86mm. It would be pointless to put a 420 cylinder on a 430 bottom end since its identical to a 430 cylinder with the wrong deck height to fit the shorter stroke of the 420, just port the 430 cylinder you already have. I have never heard of a 500 kit, PC sold quite a few 470 kits, but this is the first I ever heard of a 500 kit.

I believe there was a 420 kit for all 1980 390s available from Husqvarna. I think that was from an old service bulletin that is in Vintage Tech.

looks like the hot setup would be to just run a 430. if you really want a 390 build one of those as well

This. You already have a 430 and in the Husqvarna tech bulletin for 1982 they say to either use a WR cylinder, or if you have a CR to put a WR liner in it. I dont remember exactly what it was but there was something better about the shape of the transfer ports on the WR and once you raised its exhaust to equal the stock CR (I think 1mm) it was the best overall package.

Kart wheel, you right, use Wr 430 jug. Then there is still some cleaning up to do inside and you gonna have heck of running machine.

Ok the wr cylinder ported sounds good. I just found out the other 430 case and transmission I purchased is a 87 430 cr. Now I have the 82 430 wr but the choice of a cr tranny too? Which one?

I really enjoyed my cr390's. Maybe ill like the cr 430 even more.

All my left over parts ill box up and label.

Ok do I port the 430 cylinder the same as the 420 suggestions?