Motorcycle Racing Forum

Motorcycle Talk => Wrenching => Topic started by: bloodpressure on May 23, 2008, 03:55:20 PM

Title: 04 gsxr 750 forks
Post by: bloodpressure on May 23, 2008, 03:55:20 PM
just wondering......what does it mean when, on rebound, the forks sound like they are sucking in air? is this a definative symptom of a common problem with the forks? i can't say that i've noticed a difference in suspension performance but i'm not a very experienced rider. i do know the fork oil has never been changed although i haven't riden all that much in four years.
thanks
Title: Re: 04 gsxr 750 forks
Post by: Super Dave on May 23, 2008, 06:32:26 PM
Well, I can't hear it from here, but some times a fork with some work on it where the fluid is "working" to get through the orifices makes that kind of sound.  Not a bad thing in that case, but I can't hear it from here.
Title: Re: 04 gsxr 750 forks
Post by: cardzilla on May 24, 2008, 06:08:15 AM
I've built plenty of forks and while this isn't based on fact, it seems that the best setups all make that noise on rebound.  The shape of the piston orifices, shim stack, fluid dynamics all play a role, but as to the EXACT cause I couldn't tell you.  Rebound damping is the easiest setting to get right IMO because when it's wrong it's very noticeable... so if you like the handling don't let the noise bother you.
Title: Re: 04 gsxr 750 forks
Post by: bloodpressure on May 27, 2008, 09:51:11 PM
the thing is, these are stock forks. i thought maybe a seal was bad but there isnt any oil leak that i can see.
Title: Re: 04 gsxr 750 forks
Post by: wolf44 on June 12, 2008, 09:00:01 AM
I've had stock and worked forks make that noise.   Its normal fuild movement through the valves as far as I'm concerned.  If you change your rebound setting is it still making the same noise? 

The 04 750 forks I have on my sv make the same noise and they have FG valves in them
Title: Re: 04 gsxr 750 forks
Post by: bloodpressure on June 13, 2008, 09:09:14 AM
with slower rebound settings the noise diminishes. i think everything is ok as long as everything continues to function. i do plan on having my stuff resprung and revalved soon anyway. ive been talking with the guys at traxxion. any recommendations for those guys?
Title: Re: 04 gsxr 750 forks
Post by: benprobst on June 13, 2008, 03:04:10 PM
Quote from: bloodpressure on June 13, 2008, 09:09:14 AM
with slower rebound settings the noise diminishes. i think everything is ok as long as everything continues to function. i do plan on having my stuff resprung and revalved soon anyway. ive been talking with the guys at traxxion. any recommendations for those guys?

The guys at Traxxion are some of the best in the country. I think a couple of people out there have a little more to offer when it comes to tuning and trackside support, like LE and Thermosman, but when it comes to sending your stuff off to get worked on the traxxion guys are great.
Title: Re: 04 gsxr 750 forks
Post by: cardzilla on June 14, 2008, 05:07:23 AM
I would have to say that LE is the overall best choice just because of the type of guy Jim is... you will get top notch treatment regardless of how fast you are and you're getting YEARS of factory level experience.  All the top guys are good so I'm not slighting them in any way, just relating the great experiences I've had with LE over the years.