Cartridge emulators for 1970s forks

Found a cool product? Want to let the rest of us know about it? Do it here!

Moderator: Moderators

David Lahey
Champion
Champion
Posts: 3397
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Cartridge emulators for 1970s forks

Postby David Lahey » Sun Sep 15, 2013 11:05 am

I've been wanting to try a set of cartridge emulators for quite a while, and finally gave up waiting for someone else to give them a go in an old trials bike.
I bought a set of Gold Valves last week and have just fitted them in the TY250D forks that are on my Godden 250 Majesty.
They are meant to make the compression damping rate-sensitive, and to achieve this they use a spring loaded valve that opens relative to how fast the forks compress. They don't change the rebound damping. Standard 1970s forks have fixed size orifices for compression and rebound damping, so the compression damping is a compromise between resisting bottoming during slow compression, and not being too harsh when the suspension is compressed quickly.
So far I have tried them with the standard settings on the Gold Valves, and 15WT fork oil, standard fork springs and 50% sag, and there is a noticeable improvement in the way the front end feels when riding rocks. When I have done enough testing with these standard settings, I'm thinking of trying heavier oil to increase the rebound damping
Attachments
IMAG2059.jpg
IMAG2060.jpg


relax, nothing is under control

sharvie
Expert participant
Expert participant
Posts: 323
Joined: Wed Feb 09, 2005 4:38 am
Location: Maitland NSW

Re: Cartridge emulators for 1970s forks

Postby sharvie » Sun Sep 15, 2013 1:28 pm

Hi David,

I have been running the emulators for about 3-4 yrs, which was part of a total fork revamp carried out by Izzy at Suspensions R Us.

At first I wasn't 100% happy, so returned them to Izzy who reworked them, now great.

Using 2.5 wt oil & have the pre-load on the valve spring wound right back

A bunch of other TLR riders have done the same


Sharvie ~ Maitland NSW

eagle
B grade participant
B grade participant
Posts: 86
Joined: Sun Jul 12, 2009 1:55 pm
Bike: Honda tlr 250
Club: oakleigh
Location: Nyora

Re: Cartridge emulators for 1970s forks

Postby eagle » Sun Sep 15, 2013 3:54 pm

Hi Sharvie

What colour sping do you use & what amount of oil do you have ? are they gold valves or the copy 1s & what length does the spring end up at ?



David Lahey
Champion
Champion
Posts: 3397
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Re: Cartridge emulators for 1970s forks

Postby David Lahey » Sun Sep 15, 2013 6:45 pm

sharvie wrote:Hi David,

I have been running the emulators for about 3-4 yrs, which was part of a total fork revamp carried out by Izzy at Suspensions R Us.

At first I wasn't 100% happy, so returned them to Izzy who reworked them, now great.

Using 2.5 wt oil & have the pre-load on the valve spring wound right back

A bunch of other TLR riders have done the same

So what sort of riding do you think they made the forks work better for?


relax, nothing is under control

sharvie
Expert participant
Expert participant
Posts: 323
Joined: Wed Feb 09, 2005 4:38 am
Location: Maitland NSW

Re: Cartridge emulators for 1970s forks

Postby sharvie » Mon Sep 16, 2013 5:08 am

eagle wrote:Hi Sharvie

What colour sping do you use & what amount of oil do you have ? are they gold valves or the copy 1s & what length does the spring end up at ?


The spring is sliver, off the top of my head either 172 or 272 . . . would have to check my book

The valves are a copy, not sure what length it ends up, didn't measure at the time, but there is virtially no load on the valve spring.


Sharvie ~ Maitland NSW

sharvie
Expert participant
Expert participant
Posts: 323
Joined: Wed Feb 09, 2005 4:38 am
Location: Maitland NSW

Re: Cartridge emulators for 1970s forks

Postby sharvie » Mon Sep 16, 2013 5:24 am

David Lahey wrote:So what sort of riding do you think they made the forks work better for?


The faster rebound makes it easier to get lift from kickers etc, it is easier to hop the bike. From big drop-offs the landing is much easier on the body - no jarring of the wrists etc.

The travel is much more supple in the initial 1/2, resistance to bottoming is far more progressive and it rarely bottoms. Rebound is significantly faster, but no nasty top-out. Performance characteristics are similar to that of a modern trials fork which when matched with rear units makes the bike feel much lighter.

I think the bike requires less physical effort to ride than previous to doing the mods.


Sharvie ~ Maitland NSW

David Lahey
Champion
Champion
Posts: 3397
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Re: Cartridge emulators for 1970s forks

Postby David Lahey » Sat Sep 28, 2013 4:48 pm

I've been doing test'n'tune with the gold valves today and just like Steve and Izzy found, backing off the compression damping is the go. Standard pre-load on the gold valve spring was 3 turns and I ended up on 1 turn of pre-load and very happy with the results. Still using 15WT oil, 50% sag and standard springs.
I reckon they have improved to the point where they now work similarly well to Bultaco Betor forks and TY mono forks.


relax, nothing is under control

eagle
B grade participant
B grade participant
Posts: 86
Joined: Sun Jul 12, 2009 1:55 pm
Bike: Honda tlr 250
Club: oakleigh
Location: Nyora

Re: Cartridge emulators for 1970s forks

Postby eagle » Sat Sep 28, 2013 6:26 pm

G'day David just reading your first post& i'm thinking you didn't drilling the existing compression holes any bigger or add any more hole as it says in step 3 of the gold valve instructions or have i miss read you, i'm going to play around with mine soon as well will back the spring off then try light oil & what ever else i think might work



David Lahey
Champion
Champion
Posts: 3397
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Re: Cartridge emulators for 1970s forks

Postby David Lahey » Sun Sep 29, 2013 7:55 am

eagle wrote:G'day David just reading your first post& i'm thinking you didn't drilling the existing compression holes any bigger or add any more hole as it says in step 3 of the gold valve instructions or have i miss read you, i'm going to play around with mine soon as well will back the spring off then try light oil & what ever else i think might work

I did drill four extra 6mm holes, making six holes in total and I cut off the tops of the damper rods. The only place I deviated from the gold valve instructions was I didn't remove the centre section of the roll pin.
What forks are you using yours in?


relax, nothing is under control

eagle
B grade participant
B grade participant
Posts: 86
Joined: Sun Jul 12, 2009 1:55 pm
Bike: Honda tlr 250
Club: oakleigh
Location: Nyora

Re: Cartridge emulators for 1970s forks

Postby eagle » Sun Sep 29, 2013 9:25 am

I've got to Honda tlr 250's that i playing around with the suspension




Return to “Product reviews”

Who is online

Users browsing this forum: No registered users and 1 guest