Steering stem and fork swap

[TheLimey]

Hi, Newbie here, I have a 78 GS 750 and am refurbishing the front end, I ordered progressive springs, new seals and allballs tapered steering head bearings. I took off the front forks and the left is pretty bent and the chrome slightly cracked. (i knew it had been 'down' but its obviously worse than i thought, bloody PO) Anyways, I searched ebay and the best replacement pair that had dual disc fitment holes were from an 81 GS850, i got the forks and the steering stem/triple tree on the way.
Question1, will the 81 front end fit on my 78 without too much hassle?
Question2, will the bearings i purchased for the 78 work with the 81 and do i need to remove the old ball bearing cups from the frame? (and how is that best done?
Question3, progressive has a different part # for 78 vs 81 but the specs show very little difference, ie slightly different dia and lenghth. could i use the 78 spec'd springs in the 81 forks?
i spoke to the dealer where i purchased my new bits and i'm trying to avoid restock fees etc..
Many Thanks, love the forum, will post pics soon.

[Jason the terminator]

First off welcome to GSR.

I hate to tell you this but your 750 forks are 35mm and the 850 are 37mm so springs and seals are different. If the new stem is the same diameter as the old one the new bearings will work.

Good luck,
Jason