Topic: Front Fork Damper Valve... anyone tried these???

[CBJoe]

I've seen a reference to these fork Dampers in another thread, but I cant find the thread now.   Has anyone tried these particular ones out??

From MikesXS

http://www.mikesxs.net/mikesxs-suspension.php?category_id=6.2

Regards
Joe

[turboguzzi]

these look exactly like race tech's gold valve emulators

highly recomended

read here

http://www.gunsmoke.com/motorcycling/r100gs/gold_valve/index.html

TG

[Terry in Australia]

That looks pretty good, I might buy a set!

[jaguar]

what would they do for a CB750?  what would it take to make them work?  im rebuilding my forks right now.  got progressive springs but for another 50 bucks to make them that much more ajustable would be nice. 
more info would be great

[CBJoe]

I found the original thread where I saw them referenced..... I'm dying to find out how they compare to the race tech ones...
they are definitely way cheaper

I'd like to see some pics of the installation of them.... Joe

[CBJoe]

forgot to post the thread...

http://forums.sohc4.net/index.php?topic=29117.15

[paulages]

there are lots of articles out there explaining the benefits of cartridge forks. damper style forks have a progressive damping rate, which can result in hydraulic lock at high speeds, and mushy damping at low speeds. with the SOHC4, you've probably all experienced this the most as the mushy fork-dive they can have coming to a stop (depending on the oil viscosity).



cartridge forks use stacks of shims to control both compression and rebound damping, and have the advantage of doing so at a consistent rate regardless of velocity or force of the fork movement.



the emulators bypass the compression damping by drilling out the oil passageways too large to do much of anything, and then controlling the damping rate though a series of shims like a real cartridge fork. the rebound damping is still controlled though the smaller holes at the top of the damping rod. the emulators can be tuned to control compression damping, while the viscosity of the oil still controls the rebound.






here is a good article explaining it all:
http://www.fjmods.btinternet.co.uk/emulators.htm

[MRieck]

 CB 750 forks are as sophisticated as your storm door closer. They go up and down with a little control but that's about it High speed damping (hitting a sharp lip which causes sudden fork compression is absolutely awful). Low speed isn't worth talking about either. The 4 emulator tuning components are spring preload, screw preload on the emulator, oil weight and oil level. Your forks have to be in good shape too. These things work very well but like just about every if you don't have a decent understanding of how forks work you may end up very frustrated.

[paulages]

CB 750 forks are as sophisticated as your storm door closer. They go up and down with a little control but that's about it High speed damping (hitting a sharp lip which causes sudden fork compression is absolutely awful). Low speed isn't worth talking about either. The 4 emulator tuning components are spring preload, screw preload on the emulator, oil weight and oil level. Your forks have to be in good shape too. These things work very well but like just about every if you don't have a decent understanding of how forks work you may end up very frustrated.

tuning seems like it could be frustrating. changing the oil to control rebound is going to affect the compression still. i haven't found any good literature on tuning them, but i imagine starting with the rebound is a good idea. once you have the appropriate viscosity oil for that, the compression can be dialed in with the adjuster screw. is this how you've done it, mike?

[jaguar]

what about the springs?  the guy building the GS front end said NOT to use the progressive springs.  why?

[fuzzybutt]

i cross referenced part numbers on racetechs site and the 77-83 xs650 uses the same kit as the 73 and later cb750. i'm ordering a set in the morning

[jaguar]

i ordered a set too.  worth a try i figure

[Terry in Australia]

I'm gonna order a set and make a couple of "adjuster rods" so I can adjust them from the top of my forks, it'd be a pain in the butt pulling the forks apart to "tune" them I reckon? Cheers, Terry.

[jaguar]

whats involved in making those "rods"

[fuzzybutt]

not a bad idea Terry, i'm going to have to look into that too. i love having access to a full machine shop.

[MRieck]

what about the springs?  the guy building the GS front end said NOT to use the progressive springs.  why?

Race Tech....and most other shock people (Traxxion, Ohlins etc) use single rate springs. The progressive springs rate obviously changes as it is compressed. These guys want a single rate spring and use the oil level to provide an increase in compression damping. i.e. more oil in the tube the more resistance as the fork is compressed, less oil(greater air space) in the tube less resistance as the fork is compressed. That basic air spring stuff. With the progressive spring you are entering another variable. It can be done you just have to adjust your oil level to accomodate the spring. It will get much stiffer faster at the end of it's travel. I notice Race Tech doesn't offer springs for the CB though something in the .7kg or .8 kg range would work well for an average weight guy. I'll give them a call and see if what they say. We have used one straight spring and one progressive spring in Roadracing 600's as a side note.

[MRieck]

I'm gonna order a set and make a couple of "adjuster rods" so I can adjust them from the top of my forks, it'd be a pain in the butt pulling the forks apart to "tune" them I reckon? Cheers, Terry.

Are you going to use a "click" type adjuster to make sure damping is equal on both sides?

[jaguar]

i noticed that the progressive springs are just alittle bit shorter then the stock springs that came out of the forks.
by "stiffer faster"  what will that do to the way the bike handles?

[MRieck]

i noticed that the progressive springs are just alittle bit shorter then the stock springs that came out of the forks.
by "stiffer faster"  what will that do to the way the bike handles?

The bike should handle fine....it just becomes less compliant near the end of it's compression travel. Anti bottoming cones due the same basic thing by covering the compression holes in the damper rod as it gets close to bottoming out. It will not abrutly "lock up" the fork  (unless you are jumping the bike) or something to that effect if that 's what you're thinking of.

[jaguar]

im just trying to build a nice good handling(even at the sake of comfort) bike.
also im new at the hole this part might work thing.  so im also tring to be safe. 
what im looking for now is fork tubes that will work
what do you mean by "lock up"  i hear that ofter about forks and also the flex in the front end(reason for brace/fenders)  figure now is a good time to as questions and learn

[Terry in Australia]

I'm gonna order a set and make a couple of "adjuster rods" so I can adjust them from the top of my forks, it'd be a pain in the butt pulling the forks apart to "tune" them I reckon? Cheers, Terry.

Are you going to use a "click" type adjuster to make sure damping is equal on both sides?

Yeah I might Mike, I might see if I can find some old GSXR forks and rat them for damper adjusting rods. The probably won't be long enough, but I can fix that. Much better idea than pulling your forks apart to continually adjust, uuuurgggh! Cheers, Terry.

[Geeto67]

what do you mean by "lock up"  i hear that ofter about forks and also the flex in the front end(reason for brace/fenders)  figure now is a good time to as questions and learn

at high speeds, with the way the cb750 forks are setup as stock, when you hit a bump the fluid can't get through the hole fast enough to dampen so it tends to act like your fork is solid (called hydraulic lock - basically the fork is compressing and rebounding so fast the oil is not moving). With emulators the oil passages are made larger so the restriction is not an issue since the emulator's shims are what controls compression.

the front flex you have heard about is something totally different. Any lock up you have heard about related to that is called stichtion (sp) and is because the slider is not moving parallel to the tube but is cocked.

Jag, I don't know if these emulators work with 77-78 F forks. Someone will have to confirm that the later F fork internals are the same or similar to 73+ K bike internals.   

[MRieck]

what do you mean by "lock up"  i hear that ofter about forks and also the flex in the front end(reason for brace/fenders)  figure now is a good time to as questions and learn

at high speeds, with the way the cb750 forks are setup as stock, when you hit a bump the fluid can't get through the hole fast enough to dampen so it tends to act like your fork is solid (called hydraulic lock - basically the fork is compressing and rebounding so fast the oil is not moving). With emulators the oil passages are made larger so the restriction is not an issue since the emulator's shims are what controls compression.

the front flex you have heard about is something totally different. Any lock up you have heard about related to that is called stichtion (sp) and is because the slider is not moving parallel to the tube but is cocked.

Jag, I don't know if these emulators work with 77-78 F forks. Someone will have to confirm that the later F fork internals are the same or similar to 73+ K bike internals.   

They are the same Geeto.

[jaguar]

soo many big words...lol 
the knowlage here is amazing.

[jaguar]

just got mine in the mail...
went to slide them in the tubes to see how everything fits.....its a smaller diamiter then the damper tube.  so does that mean that they are too small?