40 Mm Forks/ Oil Wt. And Volume

[highdez1981430cr]

225 lb. rider sans gear looking to keep them high in the stroke for the sand dunes, what do you guys suggest?

And what is the best way to do it? fully collasped springs removed or just fully drain and fill?

 

[Ron]

I used 15wt Bel Ray, 16 ounces in each leg with .48 kg Race Tech springs and 1/8" preload.
Same rider weight, they work great.
Tried 20 wt first time out, but they were to harsh, 15 wt is much better.

 

[highdez1981430cr]

That is one beautiful 79 390!

That was my first Husky.

So you have 40 mm forks on your 79?

I think that is the only thing that 390 needed.

Is that a 67/68 camaro in the background?

 

[Ron]

I built that bike for my son. Finished it about a month ago.
I put a set of 40mm WR forks on it.
I think the extra inch of travel on the CR forks would have raised the front end to much and made it hard to corner. We haven't noticed any lack of travel so far.
The car in the driveway is a 67 Pontiac LeMans with GTO front clip, interior and power train (400ci, turbo 400 trans and 3:73 safe-t-trac Posi). A real GTO is way out of my reach.
I guess they call it a clone. Hasn't run in several years.
We flip flop from bikes to cars, but mostly bikes.
My son was getting a little to serious about desert racing back when he was about 18 yrs.
So we got into the cars for awhile, kind of a diversion. I got the LeMans and we built a
73 Firebird Formula for him. 462ci with a Munice 4 speed and 3:55 posi rear gears.
And I was afraid of him getting hurt in the desert. LOL
He recently sold it to some guy that shipped it to Norway.
I guess blowing the doors off his rice-burner friends cars got old.
Anyway he just got married in April and needed cash for their honeymoon and a place to live.
Pretty much broke even on it at $10,500, not counting good old Dad doing most of the work for free. Had lots of fun with though.

 

[highdez1981430cr]

We need to get a Cafe Husky group together for Elsinore!

Anyone else out there ready to hum on any sunday and get lapped by Malcolm?

 

[highdez1981430cr]

View attachment 10289 I used 15wt Bel Ray, 16 ounces in each leg with .48 kg Race Tech springs and 1/8" preload.
Same rider weight, they work great.
Tried 20 wt first time out, but they were to harsh, 15 wt is much better.

 

[highdez1981430cr]

If i want it to ride a little higher in the stroke should i mix 15 and 20 wt fork oil or run 15 wt. and increase volume?

 

[Ron]

If you want to increase the ride height you need to add preload on the fork springs or heavier springs.
Increasing the preload does not make the springs stronger, it only increases the force required to compress the spring.
Increasing the amount of oil will only have an effect as the forks get closer to bottoming.
More oil decreases the air space in the fork and causes a faster increases in air pressure, but again it won't be noticed until the forks are close to bottoming.

 

[highdez1981430cr]

Thanks Ron,i will bump up the preload.

I think i have some PVC pipe laying around that i can chuck up in the lathe to keep her riding high.

So what do you think about Elsinore?

 

[motortechniek]

sae 15 will do the job, but make sure the plastic slider that is on the innertube is new, this is the sealing part as this is worn out you the fork loss lots of damping, i never use volume to fill the fork because specialy when changing oil you never be sure all the oil is out of the fork. Best way to refill the fork is whit removed coil spring and the outer leg in its lowest stand, fill up the leg until the oil level is between 120 and 170 mm from the top, make sure when filling the legg you pump severall times whit the fork leg to allow the oil filling al the chambers.
170mm from top is big air chamber= soft fork and easy botteming
120mm from top is small air chamber= hard fork and hard to bottem.
less than 120mm will damage the forkseals easely.
if you are not happy whit the damping quality from the husky fork, an easy conversion is to fit the inner ( damping) tube from the marzocchi fork like is used standard in KTM's dimensions are the same so minor mods have to be done.
on my latest fork i have a cartridge damping system from a much younger bike fitted into the original 40 mm fork, now i can adjust compression and reboud whit several clicks.

succes and cheers

 

[highdez1981430cr]

Thanks for the info.

I am chaging the oil today so i will do the springs out fully compressed method.

Do you know what the torque specs are for the triple clamp pinch bolts and screws for the 40 mm forks?

 

[motortechniek]

I think its 18 Newton Meter

 

[scoott]

sae 15 will do the job, but make sure the plastic slider that is on the innertube is new, this is the sealing part as this is worn out you the fork loss lots of damping, i never use volume to fill the fork because specialy when changing oil you never be sure all the oil is out of the fork. Best way to refill the fork is whit removed coil spring and the outer leg in its lowest stand, fill up the leg until the oil level is between 120 and 170 mm from the top, make sure when filling the legg you pump severall times whit the fork leg to allow the oil filling al the chambers.
170mm from top is big air chamber= soft fork and easy botteming
120mm from top is small air chamber= hard fork and hard to bottem.
less than 120mm will damage the forkseals easely.
if you are not happy whit the damping quality from the husky fork, an easy conversion is to fit the inner ( damping) tube from the marzocchi fork like is used standard in KTM's dimensions are the same so minor mods have to be done.
on my latest fork i have a cartridge damping system from a much younger bike fitted into the original 40 mm fork, now i can adjust compression and reboud whit several clicks.

succes and cheers

So what cartridge are you using that fits into the 40mm stockers, if you don't mind saying?

 

[highdez1981430cr]

Stock

 

[motortechniek]

if You meen for my adjustable fork?, thats a problem there are no secrets, I'm not a comercial, i like to create and bild some things to find out if its an improvement or not, but i don't now what brand or what year of bike it coms, i have found a showa fork on the shred, it was a 43 mm fork i think from kawasaki or suzuki somwhere middle of the 90's, and i have turned the cartridge to a size that it will fit in a original husqy fork, and than i have made a fiew mod's to let it work properly.On the outside you can hardly see its adjustable, i send you som pictures in the weekend
cheers

 

[highdez1981430cr]

Nice work mate,being a machinist i love to fabricate my own things too.

look forward to seeing your work.

Darrell

 

[firecrackerkid]

I am looking forward to pics too. It is amazing how ingenious members of this group are.

 

[highdez1981430cr]

Hey Cracker,your money order should hit you today or thursday.

Got any bottle rockets for sale?

 

[motortechniek]

here are some pictures from my coverted front fork, lucky i can better handle a lathe and milling machine than taking pictures a top viewtop view whitout the rubber cap, now you see the hexagone nut whit the valve what is the adjusting wheel ( std it was round shaped, i milled a hex shape to have the original rubber cap
View attachment 10638 side view whitout and whit cap, by turning the cap you can adjust the rebound damping .
bottem view from side
bottem view ( bad picture) in the center of the hex, there is the compression screw that can be turned by a srew driver
on the outside you must be a die hard to see the mods.
my adjustable rear shocker
my 570 cc engine (oil pump type) whit home made inlet manifold ( cilinderhead from a 1985 monoshock engine)

 

[motortechniek]