GS700 mods

[MADAWG_70]

So I am back on the saddle with my 700, but faced with this issue. I have a 92 750 gixer front end and rear tire that won't fit the gs700 swingarm. Do I buy another 4.5 rim and say screw it if it don't match the front, screw up my powder coating and shove a gsxr swing arm in, or ask you blokes if a 1150 (mono shock) swing arm will fit in the bike. I am 99% sure it will fit the tire, 50% it might bolt on the 700

I am open to it all boys, please give me your input, This probably should be in appearence mods but I would rather know if the 1150 swing arm would fit, if there is a major performance increase with a gixer swing arm, or if the 4.5 is just the way to go.

Oh yeah, any one else like me looking for info, fab it first, run it again, strip it and paint it last. Skip one of these and you'll always regret it. But the I am hoping to learn after this.

[oldschoolGS]

Nice project you have there.

I'd run the 4.5, and not just because I am selling one.

First, a 160 rear -especially something like a Pilot Power- is gonna handle all the power you can generate out of a street tuned GS750.

Second, why go with the extra weight/cost of a 5.5/180 rear when it is not really necessary.

Third, adapting the GSXr swingarm is gonna require major surgery to get the monoshock linkage mounted.

Fourth, if you powdercoat the wheels dark, like black or grey, the difference in patterns between the swirl 3 spoke front and a straight 3 spoke rear are gonna be practically invisable.

Either way you go, good luck,

Ed.
2005 GSF1200SZ
1992 Duc 900SS
1983 GS750ED (being parted out)

[Billy Ricks]

A 4.5" wheel with a 160 tire is the best option. It's what I run and the 160 has all the traction you will ever need. You'll drag things before you get to the edge of the rear tire.

[MADAWG_70]

Thanks oldschool. I know that you and Billy know most about these bikes, and the 4.5 that works is better than a 5.5 that sits there with the bike down(that's what stopped progress in the first place).

[oldschoolGS]

If you stick with the stock arm, one thing I would recommend. Periodically inspect it around the pivot point for cracking. The stock arm is very light and I question its ability, in stock form, to withstand the loads imposed by modern wide radial tires along with an increase in rear wheel hp.

My stock arm was cracked 3/4 around at the pivot on the left side. I only caught it when I removed and cleaned it in prep to change out the rubber chain buffer. The crack was hiding under the buffer itself. The bike has seen several motor combos over the past 20+ yrs, the most healthy probably 20% over stock, and was fitted with a 3.5/140 rear race compound tire.

While it was hot rodded, it never was abused to the point that would explain cracking the swingarm. I am the original owner and the bike has had no crashes or curb impacts that could have caused it. It appeared to be a stress crack plain and simple.

I had it fixed and braced along the pivot point (on both sides) by a local speed shop that specializes in aluminum welding.

Not trying to scare you, just passing along what I have seen.



Good Luck, Ed.

[MADAWG_70]

Thanks for the tip oldschool, when I change the mount for the caliper I will check into having it reinforced.

If you stick with the stock arm, one thing I would recommend. Periodically inspect it around the pivot point for cracking. The stock arm is very light and I question its ability, in stock form, to withstand the loads imposed by modern wide radial tires along with an increase in rear wheel hp.

My stock arm was cracked 3/4 around at the pivot on the left side. I only caught it when I removed and cleaned it in prep to change out the rubber chain buffer. The crack was hiding under the buffer itself. The bike has seen several motor combos over the past 20+ yrs, the most healthy probably 20% over stock, and was fitted with a 3.5/140 rear race compound tire.

While it was hot rodded, it never was abused to the point that would explain cracking the swingarm. I am the original owner and the bike has had no crashes or curb impacts that could have caused it. It appeared to be a stress crack plain and simple.

I had it fixed and braced along the pivot point (on both sides) by a local speed shop that specializes in aluminum welding.

Not trying to scare you, just passing along what I have seen.



Good Luck, Ed.

[Billy Ricks]

Check the pivot bolt out close, early in the life of my bike I pulled the swingarm off and found mine was cracked.

[MADAWG_70]

Wow, do you think it was from the radials and the increased hp too, or just a design flaw in the swing arms. For the bolt on one, and the pivot point on another to be cracked, makes you wonder.

[Billy Ricks]

Wow, do you think it was from the radials and the increased hp too, or just a design flaw in the swing arms. For the bolt on one, and the pivot point on another to be cracked, makes you wonder.

In my case the bike was still bone stock. I felt like the bolt was overtorqued from the factory. It looked as if it had a void in it where the crack was.

[80GS1000]

How wide in mm is your GS750 at the pivot? That will help determine if you can use a later GSXR swingarm. I'm using a 2006 GSXR 1000 swingarm for my project as both the GS1000 and GSXR 1000 both have a pivot width of 225 mm.

[Billy Ricks]

How wide in mm is your GS750 at the pivot? That will help determine if you can use a later GSXR swingarm. I'm using a 2006 GSXR 1000 swingarm for my project as both the GS1000 and GSXR 1000 both have a pivot width of 225 mm.

Most of the GSXR swingarms are about 1/8" wider than the 700 piece. The inside of the frame has to be ground down to make room.

[oldschoolGS]

The stock alum mono arm is flyweight when compared to the later GSXR arms. Extremely light weight. It's about 1/2 the weight of the '92 GSXR750 arm I also have.

I had the GSXR arm mocked up in the '83 750 frame, its about 1/4 inch too wide at the pivot. It also quickly widens out aft of the pivot, this causes clearance problems with the frame mounted stock '83 foot controls as well.

After seeing how severe my arm was cracked, If I was building a wide tire, 100hp monoshock 750, the stock arm would either have to be heavily reinforced or replaced with the GSXR arm.

I don't think it was a coindience that mine cracked at the pivot on the load bearing, chain side.

Good Luck, Ed.

[Nicholaschase29]

I like what you are doing maddog, keep it up! After listening to what you guys are saying I'm tempted to go take a look at my swingarm. Also, Where did you get that full ss supertrapp exhaust? Thats what it looks like anyway.
Thanks,
Nick

[MADAWG_70]

Hey Nich, was readinging through this, thought I replied but was wrong. It is a stailess stee l suoer trap I got from my friend in new york. it runs great. Thanks for the encouragement, it helps when you have these two helping you along.

[Nicholaschase29]

yea, I would really like to get one, mine looks well... a picture says 1000 words.. or is speechless:-D



Trade ya!

Still looking to see where your project goes and what I can improve on on my bike, but boy why did you have to repaint the nice sidecover and tank, suppose it may match the bike better in the end.
Keep it up,
Nick