GSXR or R6 front end on a GS Frame

[Guest]

Looking to swap out the front end on my 80 GS750e for a new style front end with clip-ons for better suspension and better brakes. Does anyone know if a newer R6, CBR, GSXR front end will the GS frame or will the triple clamps off those bikes need to be machined to work?

Thank you

[mmattockx]

This has been done many times. Some of the 90's GSXR front ends will fit pretty easily but much newer than that means work on the stem to fit the new front end with the old bearings so it will fit into the GS steering head. Search "gsxr" in this forum and the performance mods forum and you will find dozens of threads to look through. One thing to note is that new forks are much shorter than the GS era forks, leading to severe ground clearance problems. If you keep the 17" front radial then you will need to fit a matching 17" radial rear wheel and tire in order to keep the handling safe and manageable.

If you simply want better suspension and braking performance it is far easier and cheaper to rework the GS forks with new springs and cartridge emulators (or a complete cartridge damping retrofit) and install salty_monk's brake upgrade kit than to make a different front end work.


Mark

[limeex2]

I have heard of emulators, but what is a complete cartridge damping retro fit?

[ericeder141]

Mark I got on the race tech website as I usually use them for my dirtbike suspension and progressive rate springs but I didn't see anything for the GS, do you know of anyone that has stiffer springs and also revalves these forks? here in jersey we have a lot of pot holes and I see the suspension taking a beating every time I ride it and I am constantly bottoming out the forks.

This has been done many times. Some of the 90's GSXR front ends will fit pretty easily but much newer than that means work on the stem to fit the new front end with the old bearings so it will fit into the GS steering head. Search "gsxr" in this forum and the performance mods forum and you will find dozens of threads to look through. One thing to note is that new forks are much shorter than the GS era forks, leading to severe ground clearance problems. If you keep the 17" front radial then you will need to fit a matching 17" radial rear wheel and tire in order to keep the handling safe and manageable.

If you simply want better suspension and braking performance it is far easier and cheaper to rework the GS forks with new springs and cartridge emulators (or a complete cartridge damping retrofit) and install salty_monk's brake upgrade kit than to make a different front end work.


Mark

[mmattockx]

I have heard of emulators, but what is a complete cartridge damping retro fit?

The vintage racers have been doing transplants where the cartridge damping system from a modern fork is installed into an older damper rod type fork. It gives you full cartridge damping with the external look of the standard fork. Not nearly as cheap as springs and emulators, though. The lowest price I know of for this work is around $500 USD and it goes up from there. It does give the best possible performance you can get from your forks, though.

Mark I got on the race tech website as I usually use them for my dirtbike suspension and progressive rate springs but I didn't see anything for the GS, do you know of anyone that has stiffer springs and also revalves these forks? here in jersey we have a lot of pot holes and I see the suspension taking a beating every time I ride it and I am constantly bottoming out the forks.

Racetech definitely offer springs and emulators for the GS bikes. Do a product search for street bikes and it should come right up: http://racetech.com/ProductSearch/2/.../GS750/1977-80

Sonic also offer quality straight rate springs and their price is better than RT's, plus the owner is a member here and very helpful if you have questions. Some people have used the emulators from Mike's XS and made up adapters to fit them into our forks. If you can't machine the adapters yourself it is probably cheaper to just buy the RT ones from the start.


Mark

[ericeder141]

Thanks for the link race tech is saying stock front fork springs a .45kg and its saying that I should bump it to a .90kg spring.... Seems line a big difference there anyone else have suggestions? I want the bike to be stiffer but not a rock lol

The vintage racers have been doing transplants where the cartridge damping system from a modern fork is installed into an older damper rod type fork. It gives you full cartridge damping with the external look of the standard fork. Not nearly as cheap as springs and emulators, though. The lowest price I know of for this work is around $500 USD and it goes up from there. It does give the best possible performance you can get from your forks, though.




Racetech definitely offer springs and emulators for the GS bikes. Do a product search for street bikes and it should come right up: http://racetech.com/ProductSearch/2/.../GS750/1977-80

Sonic also offer quality straight rate springs and their price is better than RT's, plus the owner is a member here and very helpful if you have questions. Some people have used the emulators from Mike's XS and made up adapters to fit them into our forks. If you can't machine the adapters yourself it is probably cheaper to just buy the RT ones from the start.


Mark

[mmattockx]

Thanks for the link race tech is saying stock front fork springs a .45kg and its saying that I should bump it to a .90kg spring.... Seems line a big difference there anyone else have suggestions? I want the bike to be stiffer but not a rock lol

0.90kg/mm is what you need to run without air pressure in the forks. It is correct and will give you a very smooth, controlled ride that is firm but not harsh.


Mark