Fork mods

tz375 · Post by **tz375** » Sun Nov 16, 2008 1:43 pm

From what I can see from the parts lists, it appears that the 72 forks are a "shuttle valve" design rather than "damper rod" so they can't be easily modified to use these.

Can anyone confirm that please?

Arne · Post by **Arne** » Sun Nov 16, 2008 2:02 pm

tz375 wrote:From what I can see from the parts lists, it appears that the 72 forks are a "shuttle valve" design rather than "damper rod" so they can't be easily modified to use these.

Can anyone confirm that please?

Cool, thanks. I'll have to read a bit more about front shock setups as I don't know much about them.

Arne

rngdng · Post by **rngdng** » Sun Nov 16, 2008 6:08 pm

The early forks were referred to as "Ceriani-type". They are very different. If they are really copies of Cerianis, they shouild be pretty good.

Lane

GT Tim · Post by **GT Tim** » Sun Nov 16, 2008 6:35 pm

The 72 GT750 forks are fine, relatively. It's the shox that sux!!!!

tz375 · Post by **tz375** » Tue Dec 02, 2008 6:55 pm

When I fitted the cartridge emulators and assembled the forks there was a lot of stiction with NOS LeakProof seals, so I just stripped the forks and fitted a pair of new seals from Mike's XS along with a pair of seal washers and fork boots.

What a difference - at least in static mode. We'll know in spring when the snow recedes if they are an improvement in the real world, but I have high expectations.

rngdng · Post by **rngdng** » Tue Dec 02, 2008 7:33 pm

I just bought a set of the emulators, myself. Eventually, I'll get around to installing them!!!

By the way, "Leakproof" seals are the only seals I've ever had problems with: they suck!!! Stay with OEM.

Lane

tz375 · Post by **tz375** » Tue Dec 02, 2008 10:51 pm

Lane,

I know, I know.

They were old and lying on the shelf so I thought "why not", after all the only two times I used leakproof seals before, they were a total disaster so third time was supposed to be lucky.

They are now appropriately filed in the garbage bin.

iceman_ca · Post by **iceman_ca** » Sun Jul 31, 2011 11:10 am

Old thread I know, But is everything functioning properly.
I read somewhere else the forks became to stiff with oil in them.
Have there been revisions since this thread was created?

thanks guys

tz375 · Post by **tz375** » Wed Aug 24, 2011 2:49 pm

Yes. After I fitted the adapters things started to clear up and now they move nicely. They are fairly stiff but I took a lot of weight off the bike and didn't adjust spring rates for that change.

They should be fine as they are now.

vmxwinn · Post by **vmxwinn** » Thu May 14, 2015 10:24 pm

tz375 wrote:Yes. After I fitted the adapters things started to clear up and now they move nicely. They are fairly stiff but I took a lot of weight off the bike and didn't adjust spring rates for that change.

They should be fine as they are now.

Hi TZ375, Would you mind sharing your current fork setup?

My GT550 suspension, for a better lack of words, sucks! Forks have fresh seals and oil and the are so soft under damped and springing that its dangerous. Shocks not much better but that is pretty easy to fix. Just buy good shocks.

Anyways thanks for your input.

markush · Post by **markush** » Tue May 26, 2015 4:04 am

Hi!

another mod: air support at GT380-Fork

see also:
http://www.mariolange.de/wbb2/thread.ph ... #post12083

( https://translate.google.de/translate?h ... 3post12083 )

Markus

tz375 · Post by **tz375** » Tue May 26, 2015 8:38 am

vmxwinn wrote: Hi TZ375, Would you mind sharing your current fork setup?
My GT550 suspension, for a better lack of words, sucks! Forks have fresh seals and oil and the are so soft under damped and springing that its dangerous. Shocks not much better but that is pretty easy to fix. Just buy good shocks.
Anyways thanks for your input.

Set up now is two inches shorter than stock to lower the bike for drag racing

But the original forks have Emulators sitting on a short spacer to allow oil to pass around the adjuster nut. Damper rods were drilled out as normal for emulators and I also brazed the small rebound damping holes and redrilled them to work with the Progressive Suspension fork springs. I also use a stiff fork brace to stiffen the front end up a bit.

They are still heavy and small and not anywhere close to modern forks but they seem to be much better than they were. If you need to buy a set of sliders for a second disk, it might be smarter to look into an SV650 front end. The older models look much like a GT and you could use a GT hub with SV disks and calipers but would probably need spacers to get the disks in the right place relative to the calipers.

I have not measured a set of SV forks but that may be the way to make a huge difference.

Fork mods

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