question on servicing '88 Husky forks...

[everfree]

Hey guys,
I'm servicing my '88 430 WR forks... Husqvarna forks not the White Power forks.

They would always bind initially and seem to drag too much and I'd like to fix that. Upon disassembly, I noticed the culprit seems to be the top off washer on the inner spindle.

As you know 88 forks have some differences from the 87 forks. The top off washers and spindles are different and so are the part no's. There's other part differences as well.
15-12-373 : 87 top off washer
15-12-487 : 88 top off washer

Anyone have a problem like this on their '88 forks? The 88 washer is wider and stiffer... more drag?
I will try the 87 top off washer for fit.

 

[everfree]

'88 fork spindle with top off washer...


comparing 88 washer (lower one) with 87 washer (top one)

 

[justintendo]

interesting..never noticed a diff in parts..just thought the dual piston brembo forks were the same inside for the most part..i believe ive only ever seen the normal top out washer. the one that looks like a thick band is strange!
i personally run synthetic atf in mine, 450-500 ml per leg..i weigh 240 with gear and this works well in the woods and trail. only when really pushing hard in 3rd and 4th will the springs let you know you should the correct ones for your weight..
check your upper and lower teflon bushings to make sure the coatings are still there..

 

[2premo]

it appears to be tapered so the area affected should be similar
but good question

 

[everfree]

interesting..never noticed a diff in parts..just thought the dual piston brembo forks were the same inside for the most part..i believe ive only ever seen the normal top out washer. the one that looks like a thick band is strange!
i personally run synthetic atf in mine, 450-500 ml per leg..i weigh 240 with gear and this works well in the woods and trail. only when really pushing hard in 3rd and 4th will the springs let you know you should the correct ones for your weight..
check your upper and lower teflon bushings to make sure the coatings are still there..

The thick top off washer from the 88 is strange. First time I've seen it too. It is not just plastic, it has wire in it. I wonder if orientation matters, like 2premo noticed.
I'm used to the 87 plastic top off washer.

I run 7.5wt to 10wt fork oil, 470 cm per leg. The owners manual calls for 450 to 470ml, 5wt fork fluid.
In my experience, 5wt gave too light damping. I was going to try 10wt.
Getting the spring right is important too.
Old magazine reviews of these forks talk about cutting off 1 turn of the spring for stiffer spring rate and adding a pvc spacer to get the static sag right.

Good suggestion to check the bushings. I noticed they are coated on the inside... makes sense, the fork chrome tube slides against the fork slider lower body.

 

[justintendo]

thats what i did, cut my stiffer pair down and added spacer..helped alot for more aggressive stuff..but i would like to get proper springs.

 

[GaryM]

Would like to see the top of damping rod without the larger ring installed just to see any difference. Also is the bottom of the
damping different also ? The 87 has much different set also with that floating/sliding valve in a cage in the bottom. How about a pic
if possible ?

 

[everfree]

Would like to see the top of damping rod without the larger ring installed just to see any difference. Also is the bottom of the
damping different also ? The 87 has much different set also with that floating/sliding valve in a cage in the bottom. How about a pic
if possible ?

Gary, good suggestion. I have a set of 87 forks to rebuild as well. I'll get some comparison pics.

Someone sent me the '88 Parts Manual, which I didn't have... I only had an 87 Parts Manual.

In comparing the differences, these parts have different part numbers:
1. damping spindle
2. top off washer
3. damping valve housing ('88 added a bolt hole to keep damping holes aligned. For valve bolt below)
4. damping valve bolt (only on the '88 forks)
Note:
Above list is only for comparing '88 and' 87 forks of XC or WR type.
XC and WR forks have part differences, because XC forks are longer and have more travel. In '88, there was no CR with Husky forks and no 500cc bike sold (at least the parts list doesn't show it).

 

[hva-factory]

The later part is NOT a top - out washer. It is a sliding seal that makes the oil go through the fork valves. If you were to use it on the earlier forks, you would not get the one - way valve effect of the correct top out washer. I will add some pics of the later fork that does not use a top out washer - as it has a top out spring....

Andy.

 

[hva-factory]

 

[hva-factory]

 

[everfree]

Thanks for the correction, Andy. The pics are great, and the fork cut-outs really help show the components.
This was helpful to visualize how the fork works.

 

[Joe Chod]

the pre 87 washer controls the flow

the post 87 does not...it is actually a seal and the rod does the dampening and flow like most other forks

Andys pictures help alot...thanks Mate!

The shape on inner circumfrance of the pre 87 washers actually relate to the flow of oil on dampening.

 

[slosh]

Bit off topic, but were the later forks much better than the plush early ones?

 

[2premo]

Bit off topic, but were the later forks much better than the plush early ones?

the valving of the earlier forks was plush, but the seals are WAY better in the latter ones
you can migrate the valving into the newer design

 

[Joe Chod]

My opinion on the 86to 88 forks is not high. not as prone to leaks but the double bushing made for a mid stroke harsh that I hate.

Just my 2 cents

 

[2premo]

My opinion on the 86to 88 forks is not high. not as prone to leaks but the double bushing made for a mid stroke harsh that I hate.

Just my 2 cents

they did add a tick of harshness, but the 86 were still the early design, it was only the 87-88

 

[hva-factory]

There are issues with all 85 - 87 forks in that the later chrome stantions were updated to have 4 x 6mm diameter holes around the bottom. These allow the oil to flow between the fork and up to the seals(and back), giving the oil somewhere to go and not to pressurise the seals or cause cavitation. If you have a milling machine and carbide cutters, you can modify them all to work fine by cross drilling them(they are hard!) - you need to do the corresponding parts too as shown in the pic attached. Also, whilst you have them apart - replace the aluminium tapered Valve ring with one of our Bronze ones… Use 7.5w oil and 400mL is enough, as all the valving is at the bottom of the fork, they only need oil there… If you put 500ml in you will blow the seals.

Hope this helps.
Andy.

 

[GaryM]

Yes already have them drilled. Recomended from race tech and went to 10 wt oil but will try going to 7.5 wt. With the 10 also lowered the oil amount. Also
found rough bore on on old fork legs and very carefully honed the interior bore. Slide much better.

And well - a little secret a bit a Tungsten Disulfide (WS2) nano powder burnished into the bore also.
Even talked to the Nasa guy who invented/ discovered this product. WS2 is now in many places on my bikes.

 

[everfree]

Yes already have them drilled. Recomended from race tech and went to 10 wt oil but will try going to 7.5 wt. With the 10 also lowered the oil amount. Also
found rough bore on on old fork legs and very carefully honed the interior bore. Slide much better.
And well - a little secret a bit a Tungsten Disulfide (WS2) nano powder burnished into the bore also.
Even talked to the Nasa guy who invented/ discovered this product. WS2 is now in many places on my bikes.

This is interesting. Maybe that's why my '88 fork motion is sticking. Where's the potential friction? Rough on the inner fork legs or inner chrome tubes?
WS2 is $330 for 50 grams.