gs1000g mild cafe build

[Chuck78]

Cool...jack up the rear shocks a bit and you should be at around 4" of trail, less than stock, sportier steering!

what was the rake of the Kat that the girls came off of vs the stock gs1100g rake?

if you could raise the rear enough to get the head tube / fork angle within 1 or 1.5 degrees of the Katana's spec, you will have a great responsive steering geometry

[thebrandonbeezy]

I believe the gs had 30 or 31 and rhe kat was high 20s i think 28. Ill look into it more tonight

[Chuck78]

GS is either 28 or maybe w7. Newer sport bikes 90's & up push the limits 25.5 down to 24, some very recent bikes 23 or 23.5 (too steep, steering damper required).

Ninja 250's I believe we're at 27 which surprised me. Shooting for 26.4 down to low 25's on a GS is a very sporty treatment, but you have to use an online trail calculator to keep the trail in spec. It is far more important than rake. Steepen the rake until you arrive at 3.8"-3.9" trail.
A trail calculator will require front tire diameter (or radius, more precisely is what is actually used), triple clamp offset (need to measure very precisely), & head tube rake angle or castor. Make sure bike I'd on a perfectly level surface or tires are shimmer up to achieve perfect level bore trying to put an angle finder on the fork tube or head tube.

[thebrandonbeezy]

According to the Google, rake is 28 and trail is 4.4 on the gs stock, and the kat was 25.3 and 3.9

[thebrandonbeezy]

Ok so just messing around with the calculators, with the 19 up front my current rake is 25°dead nuts on the upper fork tube. With a trail of 4.49

[thebrandonbeezy]

Sorry 4.41 and recalculated for the 110/80r17 is 3.888

[thebrandonbeezy]

Thats if the rake stays at 25, which i can adjust the rear to bring that in where I need

[thebrandonbeezy]

And so it has begun lol the only problem with the swap so far is the rotor diameter is 250 mm compaired to the gs 295 mm. CASH ME OUSIDE HOW BOW DAT

[Chuck78]

Hey Brandon FYI I just picked up an underslung 1989 GSXR750 caliper and sweet looking "lightened" ( cast with lots of holes in the middle to remove material) hanger that fits our 20mm rear axles. The hanger also shares the same bolt pattern as a conventional top mount (not underslung) GS500F rear caliper. Not sure on the GS500F rotor size. Some early gsxr years used 220mm or 240mm rotors.

http://www.ebay.com/itm/162405733966

Also I have found shopping the EBC catalog for pad dimensions can yield other pads with the same backing plate that have the friction material at different heights to accommodate slightly different rotor sizes. Look into rotor diameter specs for the GS500 and early GSXR750 and 1000 or 1100. I think you can make something like this work. What I have would work awesome for yours except you would need to weld an underslung brake hanger mount on your swing arm. The GS500E/F might be the nearly bolt-on ticket for yours if they run a 250mm rotor. Mine is definitely going to be used, not looking to get rid of it!

[Chuck78]

Keep in mind your rake and trail when selecting tire sizes. Basically all the rear tire size does is adds or removes rear ride height, which slightly changes the rake up front. Front tire diameter does this but has the opposite addition or subtraction effect with regards to changing diameters. Also in addition to changing the rake which affects the trail, the smaller tires diameters definitely decrease trail as well without figuring in the rake change incurred by the same factor.

If you get your trail down to 3.95"-4.05" you will have a very nice handling bike. Get it down to 3.85 and you will have a very quick steering very sporty feeling bike, and the bike will feel a lighter weight when you turn, but may feel a little more twitchy at extreme excessive speeds. Adjustable rear shock height is awesome to dial this in

[Chuck78]

Looks like all years (1989-2010) GS500 use a 250mm rotor. The stuff off the bike the rear wheel was sourced from would also work, right?

[thebrandonbeezy]

Im wondering what the kat 600 axle diameter is, with the gs caliper in place mounted where it should be "with only the brake stay" it ever so slightly rubs the rim when the spokes come around

I may end up swaping the kat rear caliper and rotor as its the same bolt pattern and mint as this vx rotors should have been changed a very long time ago haha. If the kat axle is smaller thats not a problem as i have a lathe to bore it out, but i wouldn't want to machine a spacer if its bigger.. you know

[thebrandonbeezy]

Looks like all years (1989-2010) GS500 use a 250mm rotor. The stuff off the bike the rear wheel was sourced from would also work, right?

It should but the rotor is trash so im going to see how the katana stuff i alread have fits first before i venture back onto ebay

[Chuck78]

Looking at your picture, that rotor looks identical to the GS500 rotors I saw on eBay used. You need to confirm the cross reference though

[thebrandonbeezy]

I agree, also the vx800 and the kat 600 share the same caliper from what i just found online. So theres a step in the right direction