2005 GS500F front end swap to GS750E or ES?

[mikerophone]

Anyone done a 500F front end swap to a late 70's 750E? or an 80-83 750ES?

I can get the forks, triple tree and calipers for a song and would love some advice. What else might I need?

According to All Balls the swap will work with my either of my 750's but doesn't guarantee a fit die to possible different stem lengths...any concerns I should look out for there or anyone know if the lengths are the same? Will I need the front wheel too or can I adapt it with spacers to mine and if so, will the new calipers bolt up?

I'll search some more as well, but is there a front end swap compatibility guide here somewhere? I've found a few on other sites, but trust this site more than any other.

TIA

 

[mikerophone]

Anyone? Don't want this deal to slip away but don't want to buy something that won't work either...

 

[garagepunkfan]

if i recall correctly, the stem is too short to be used on the earlier GS frames. that, the need for upgraded springs, the fact that its the same 37mm tube size as yours and is only single-disc outweighs any advantage of using it outright. however, the front wheel may be worth snagging as it shares the 15mm axle size of the classic GS bikes and is drilled both sides for twin discs. i'm going on the assumption here that your bike an 83-85 GS750E?

(EDIT) nevermind, i see the '83 GS750E listed in your sig.

you may want to ponder this...the 37mm tube size of your stock front is pretty adequate for the size and weight of your bike, assuming that it's worth putting work into, tubes not rusty, etc.

doing the Kawasaki Twinpot brake conversion, disabling the anti-dives, a fork brace and good springs with a 17" front wheel will give you everything you would ever want in braking/handling and the best part is that the 100/90-16 tire that was fitted to the 83-85 GS750E has a diameter of 23.09 inches, while a 120/60ZR-17 tire has a diameter of 22.67 inches; a marginal reduction of .420" in diameter, so it will look at home in your front fender.

your 1978 GS750E Project is a good candidate for a complete front swap, but the GS500E front is not in the cards for that one either....

 

[mikerophone]

if i recall correctly, the stem is too short to be used on the earlier GS frames. that, the need for upgraded springs, the fact that its the same 37mm tube size as yours and is only single-disc outweighs any advantage of using it outright. however, the front wheel may be worth snagging as it shares the 15mm axle size of the classic GS bikes and is drilled both sides for twin discs. i'm going on the assumption here that your bike an 83-85 GS750E?

you may want to ponder this...the 37mm tube size of your stock front is pretty adequate for the size and weight of your bike, assuming that it's worth putting work into, tubes not rusty, etc.

doing the Kawasaki Twinpot brake conversion, disabling the anti-dives, a fork brace and good springs with a 17" front wheel will give you everything you would ever want in handling and the best part is that the 100/90-16 tire that was fitted to the 83-85 GS750E has a diameter of 23.09 inches, while a 120/60ZR-17 tire has a diameter of 22.67 inches; a marginal reduction of .420" in diameter, so it will look at home in your front fender.

Thank you for the info garagepunkfan!! :biggrin: I will look into the Kawasaki Twinpot conversion for my ES and maybe a 17" wheel at some point.

The 78 750E is a project bike that I am/will be building with a friend and we were looking into front and rear end options when this came up on Craigslist, so the hope was that we could maybe make this work for that bike, but after your post, I looked closer at the photo the guy has listed on CL and realized it was only a single disk, single caliper, just large and drilled. Our bike already has the dual front discs, but only single pot calipers, but luckily the forks are not in bad shape, think we'll just get some Sonic Springs and find the right fluid weight for the stiffness we want and be happy with that. Really do appreciate your insight!

 

[Guest]

Thank you for the info garagepunkfan!! :biggrin: I will look into the Kawasaki Twinpot conversion for my ES and maybe a 17" wheel at some point.

Twinpot brake thread: http://www.thegsresources.com/_forum/showthread.php?140253-Twinpot-Brake-upgrade-on-78-Skunk

think we'll just get some Sonic Springs and find the right fluid weight for the stiffness we want and be happy with that.

Add in a set of cartridge emulators and you will have a very decent front end that will lack for very little.


Mark

 

[garagepunkfan]

Add in a set of cartridge emulators and you will have a very decent front end that will lack for very little.


Mark

i'm not sure about the cartridge emulators with the anti-dive forks, seems like i read here somewhere that the blockoffs that connect the two ports that are made for the anti-dive forks accomplish the same metering effect?

 

[Guest]

i'm not sure about the cartridge emulators with the anti-dive forks, seems like i read here somewhere that the blockoffs that connect the two ports that are made for the anti-dive forks accomplish the same metering effect?

The anti-dive does nothing similar to the emulators. I expect you would have to deactivate the anti-dive to use the emulators, but that is what you want to do anyway. All the anti-dive does is increase compression damping, making the fork harsh over bumps when you want it to be supple. The emulators increase the low speed compression damping for a nice firm feel on smooth road but they blow off and absorb bigger hits without beating you to death or upsetting the bike.


Mark

 

[mikerophone]

Good info here guys - thanks for sharing!

 

[Big Rich]

I have GS500E forks on my GS450 (the E forks are easier to work with when changing springs / seals than F forks). The GS500 steering stem is way too short to be used, but I used a complete triple tree from a GS850G since they share the 37mm legs and have the same fork spacing. The good thing about GS500 parts is the sheer abundance of them.

That being said, I think a better swap for the GS750ES is pre-98 Katana forks. Dual discs, 41mm forks, and a 17" wheel as well. Fwiw: the GS500 has the same wheel as the Katana, it just has a plastic cap covering the rotor mounts on the left side.

 

[mikerophone]

...better swap for the GS750ES is pre-98 Katana forks. Dual discs, 41mm forks, and a 17" wheel as well.

This. I want to do this. I've heard people say that the GSXR is the way to go, but I am not sure of the differences or benefits of the GSXR vs Katana, Katana is sounding sweet to me, slap some cartridge emulators in there and a fork brace and springs but will need to do more research when I am ready. Thanks for the info.

 

[garagepunkfan]

The anti-dive does nothing similar to the emulators. I expect you would have to deactivate the anti-dive to use the emulators, but that is what you want to do anyway. All the anti-dive does is increase compression damping, making the fork harsh over bumps when you want it to be supple. The emulators increase the low speed compression damping for a nice firm feel on smooth road but they blow off and absorb bigger hits without beating you to death or upsetting the bike.


Mark

i was referring to the Demon Speed aftermarket block-offs that are sold to deactivate the anti-dive. they connect the two ports in the fork legs.

if you do run emulators i believe a flat block-off plate is needed that blocks the ports altogether and you need to drill above and below the oil ring in the anti-dive circuit inside the fork.

i believe Salty Monk runs GS1100E forks with Mikes XS emulators in this fashion using Sonic springs with very good results