'85 500 engine vibration cure?

I am rebuilding my '85 500 to do some racing....

I would be very grateful if anyone could tell me how to cure or at least reduce the amount of vibration that this engine produces?

I'm about to strip the engine and replace the main bearing etc as it hasn't run for at least 15 years so this would be a ideal time to do any work necessary to deal with this problem.

If nothing can be done engine wise are there any other suggestions?

Many thanks in advance.

If your crank cheeks are round then should cut them to 87 specs. Looks like cutting a L shape on both sides of the big end pin. This removed some weight and gave a better balance factor to the crank. I've got the specs if you call give them to you. Later George

The inserts that go inside your handles bars,made by Fasst[spelling] help alott. I've never had much luck with silicon or rubber bar snakes.Make sure you always check motor mounts and swing-arm bolt. I've always felt the first single shock Husky's vibrated more then the older twin-shockers.

'serious competition' is only in my mind at the moment but you never know, there might be life in the old dog yet

Thanks for the suggestion I'll certainly give that a go. Ta.

I would be interested to hear about this mod so if you could PM with a number to call that would be great.

I raced an '84 twin shock 500 as well but can't remember if it suffered as much... pain fades with time....

I'll look Fasst up. Ta very much.

There is no cure. George built my 500 and did all that plus more but at the end of the day they just vibrate too much. Husky shoulda mounted the engines with at least 1 more mount under the cases plus head stay. The bar tricks are a waste of time (tried 'em all). You can hang on for a 15 min moto but back-to-backs aren't fun.

My Dad has a 1985 WCSS 500 and we put an additional motor mount directly under the crank..worked well..a trick told to me by the guys at Up-Tite Racing..

I'm willing to try anything (apparently.... but that's another story) but I do listen to personal experiences.... I must admit I did 'Gulp' when I was told the price of the Faast Co Flexx bars... £330 plus del which is about 1.5 times more expensive than in the US... I think that might be a last resort with a try before I buy...

BTW: Used to have an '82 500 like yours... we called it the Silver Streak... would love to get one back again.

As I am in the first stages of rebuild mode it would be an ideal time to do something like that. Would you care to past on how it was done?

Cheers.

Yes please share that one!!

I spoke to George at Up-Tite Racing last night (my time) - thoroughly nice chap.

He said that the extra mount should be directly below the centre of the crank but as my cases are Magnesium this could be a problem getting the mod done. He also suggested that I lower the compression by machining more material out of the head. He said that in view of the intended use power was not a priority - hanging on was couldn't agree more....

So watto450 could you take some snap shots please when you next see your Dad's machine and pop them in here that would be great. Ta.

compression

Hello Husky37, did George say how much material to remove from the dome in the cylinder head? I'm thinking of doing this mod so any detailed guidance would be useful.

Am I being stupid, I know the 500 is tight on clearance between the cylinder fins and the exhaust, but couldn't you just use a thicker gasket to lower the compression?

Cheers
Luc

Hi Luc,

Sorry but he didn't say how much to remove but when I find out I'll post it. Mine's a water-cooled '85 so I'm not sure if that makes any difference as to how much 'meat' you can remove for either my head or an air-cooled head.

I thought the same as you with regard to a thicker head gasket but I'm un-sure if that will give you enough of a change in the compression ratio to make the difference.

I do have somebody in the UK who can do this... just checking all the details. Will post when I have them.

Would this approach sound sensible: remove 2.9cc of material from the dome to lower the compresison from 9.5:1 to 9:1?

Cheers
Luc

Rajobigguy speaks the truth. If you raise the cylinder you mess up the port timing and widen the squish distance. My own 500 1984 had:

1. Stock height cylinder
2. Crank trued and balance mod
3. Head mod for lower compression
4. Timing to 1.5mm BTDC
5. Boyesen reeds

It went from an unbearably vibrating mess to a tolerable vibrating mess.
It's a significant improvement but it's still not a sewing machine. I don't remember where I got my crank specs, but if George has some that's the way to go. And extra mounts would be icing on the cake!

Hi Rajobigguy,

Did you put the extra gaskets at the base of the Barrel because I thought of putting the extra gasket between the head and the Barrel which would not effect the port timing... just might cause a problem sealing the head properly.

Thanks for the heads up though (No pun intended )

I always try to learn of other people mistakes but never seem to learn from mine.... such is life.