Best year for the 390?

I've been racing a 1974 250 mag for a couple years and having a great time. I know all there is to know about a 250 mag. I'd like to have something with a little more power and suspension (for my height and weight). The next class up for me locally would be GP1 (1975-81). A guy at the races today let me take his 1978 390 for a spin. I liked it. Can the folks that know the 390's from that period weigh in on the best year(s) to look for?

thanks John

Whilst this advice is probably correct for most people, I would argue that you ideally need to be quite a tall guy to enjoy the later 390 due to the very high seat height. If I were ever to get another 390 I would look for an earlier model for this reason, but then I am a bit vertically challenged

easy to "WR" the suspension and lower it. mate has used wr sliders, cr damper rods and slips a top out spring on to get rid of the poxy plastic washers and he ends up with a tad more travel than the wr standard.

I'm 6-2, and on a good day, weigh in at 250 + gear ...I like the input gents, thank you. I'm quite scrunched up when seated on the mag, but after racing it two years, I've adapted...but, now when I ride or race my modern 2011 KTM, I feel high and awkward. So maybe a 78/79 would be a good middle ground. putting around on that 1978 390 on Sunday, I felt good. So much more height (at least it felt so) than the mag and plenty of power. I'm tossing around the idea of selling the KTM to help fund the husky. That would leave me with no modern bike. Do any of you ride a 390 in modern desert/moto events?

ive basically given up on my kato 300. I ride the 400 or 510 pretty much everywhere. I find its only the brakes that are a disadvantage. if you wacked a good later model forks and disc you wouldn't be that badly off. they are a lot softer and plusher than the new bikes but they just ride over everything rather than picking your way through.

Depends on the type of riding you'll be doing.77,78 has a sharper steering rake than the later ones.High speed vs quicker steering

I know I'm biased, but I love the 78's. Both of mine are WR's and have plenty enough suspension travel for me providing I avoid the modern "slot car - jumper cross" tracks.
Drum brakes ..... if you want bad, just try racing a 73 CCM ! I find the Husky single leaders good enough.

The 1980 is the best. Most of this is for the motor. Husky beefed up the cases and I belief strengthened the rod/bearings. One could change
to the 420 top end back in the day. The earlier motors would have not been able to handle that. George at Up-Tite to this day converts the 80/390 to a
412 displacement if one desires. It also has longer suspension and overall length, making it very good for whoops and overall stability.
And yes, converting to the 40mm forks dual brake system is possible too.

The 412 bike you describe would be wicked as a WR ...

I am building a 390WR on the 1977CR /1978 Auto frame that will have about 10" travel front and rear. I have to rebuild the remote Ohlins and will likely put a set of 40mm WR forks on the front. I had a 1978 ACC 390 in 1981 and loved the handling. I had tried out a 1980 250CR that a friend had and the handling blew my mind. So when I had the opportunity to buy the ACC with a shot 2nd gear for $500 I grabbed it. As it turned out, the orginal owner never paid the sales tax and titled it(being a dealer) I could not register it without paying sales tax on the $2000 purchase price. I realize now that $100 tax to register it was a foolish stand on principle but then $100 then was worth a lot more than $100 today.

I would get a '79 or '80, basically the same chassis as up to '82 if you swap to the 40mm forks. Engine wise, the '80 might be the best but they are all very good.

79 OR! I love mine. 5'8 and it is low enough but way taller than an earlier model. Then swap the front end out for a 40mm disc front end. I've got an 85 front end on mine with the 85 bars too and it's a huge step up from stock.

I liked them all.

Had a 77 that came with purple tank. Raced at least twice and sometime 3 time a week. Great bike

It was painted black and added the Howerton laid down Fox shocks for the next year. Never was a problem with the bike ever. Well flat tires

Had just great fun on that bike

But enjoyed the 1980 390CR bike as well. Just so many good times and lots of racing. All were great.

Dont swap on a disc front brake if you plan to race vintage with it.

I have a few husky racers and feel the 1980 CR is far and away the best for MX and I love the 79 OR in the woods...my 77 is also a great bike....if I had to pick one for the class you mention riding in the 1980 rules the choices by far IMHO..

If your class is up to '81 an '81 430 would be even better, you could probably get away with an '82 since most organizations have a "like design" and they are basically identical other than tank color and the bare cylinder on the '82. If you want a 390 the '79 and '80 frames are basically the same. I would look for an '80 but dont pass up a '78 or '79.

The 79 does look a bit different to the 80 model, could you update the look of the 79 if wanted?

I think you can update the '79 to the '80-'82 style seat and side panels but you would probably need to weld on some captive nuts to mount the rear of the side panels. I'm not sure about the seat but I am sure the '80-'82 seat could be made to fit. The geometry of the '79-'82 frame is identical so the real difference is the forks and swing arms of the '80-'82 bikes.