'77 710...ish

[unfocused]

i started to build a 710

now i've deviated from a typical 710 build... if there is such a thing LOL

 

[unfocused]

I toss around ideas with a mono shock. To many variables that can't be taken into account without building. Battery and electronics locations. Gusseting and bracket work for the mono shock. A lot of other things to figure out.

But since I am building a '77 and not a '02 GSXR it was easy to decide on the final direction of the rear suspension.

 

[unfocused]

Wanted as much OE as I could use...

Shocks are dead and only mocked-up.
Rear wheel isn't fully assembled.
But the mirrors look cool LOL

 

[unfocused]

Once I started in on the swap, things that weren't anticipated pop out.
These are the things that make you change directions or give up...

 

[Guest]

Dual shock setup looks goofy with that extended swingarm in my opinion. If you want help with the monoshock conversion, let me know. I monoshocked my GS1000 and it works great. It is a fair amount of work to get all the variables correct.

Is extended swingarm for looks or are you going drag racing?

 

[unfocused]

It's your opinion and I respect this. But when I post some pics with the seat and rear cowling/lights it might alter your perception.

Street/drag racing, timed speed runs and more. Then I can look good at Bike Week, The Turkey Rod Run and more.
I am not going to install a 1000cc engine, extend the swingarm, upgrade the suspension and more just for looks... LOL

The dual shocks allow me to strut it for racing purposes.
The extended swingarm will be modified for a more period correct look.

Adding the mono shock and the fabrication involved wasn't the issue. Building something that looks more period correct was.
Plus the 750 frame is from what I've learned, shorter than the 1000. I wasn't going to fight issues on battery and electronics locations/installation just for the appearance of a mono shock. Also, if I wanted to really use mono shock setup, I would of chosen a different year of donor.
In the short time of this build, I've learned a lot. Thanks for the offer and share some pics of your build. I'd like to see the setup. See if we think alike...

I'm building a '77 GS750 or so the registration says, not a '02 GSXR.

 

[storm 64]

I can't wait to see this finished project...

 

[Guest]

It's your opinion and I respect this. But when I post some pics with the seat and rear cowling/lights it might alter your perception.

Street/drag racing, timed speed runs and more. Then I can look good at Bike Week, The Turkey Rod Run and more.
I am not going to install a 1000cc engine, extend the swingarm, upgrade the suspension and more just for looks... LOL

The dual shocks allow me to strut it for racing purposes.
The extended swingarm will be modified for a more period correct look.

Adding the mono shock and the fabrication involved wasn't the issue. Building something that looks more period correct was.
Plus the 750 frame is from what I've learned, shorter than the 1000. I wasn't going to fight issues on battery and electronics locations/installation just for the appearance of a mono shock. Also, if I wanted to really use mono shock setup, I would of chosen a different year of donor.
In the short time of this build, I've learned a lot. Thanks for the offer and share some pics of your build. I'd like to see the setup. See if we think alike...

I'm building a '77 GS750 or so the registration says, not a '02 GSXR.

Period looking drag bike with struts makes sense....will look trick with the right bodywork.

I have my rear suspension apart at the moment to get the rear shock serviced and resprung. Here's the top portion of the monoshock mount on my bike. I used box section steel tubing and then braced the frame around the upper shock mount and swingarm pivot for strength and to prevent twisting. The upper shock mount bracket is from a 92 GSXR 1100. The electronics are on a tray under the seat and the battery box sits under the seat as well.

The bottom bracket is boxed in tabs welded to what used to be the centerstand frame cross member

 

[Steve]

Have you calculated the new spring rate necessary for the stretched swing arm? :-k

.

 

[unfocused]

Have you calculated the new spring rate necessary for the stretched swing arm? :-k

.

You would ask me about that LMAO...

I've spent the last 3 days in some sort of search/research for where the f$%k to start.
The shocks on there are dead and just for mock up and rolling around. They're 12.6" stock and I have no specs and don't expect to find any.
Obviously the fronts are OE adjustable GSXR and I'll need those for weight transfer, not high speed lean angle corners.
Right now im leaning towards an 11"~12" shock [natural ride height] with with somewhere around a 6-700lbs spring, 7" or 8" long.
How far off em I ??? LOL

...and then there's a price to pay, to be able to play. Ouch!!!

I've read enough about this to realize not all springs are the same even though they may "rate" the same.
Not a lot of info to be found for any type of build like this.
All modern info is for mono shocked bikes but the springs rates are completely different or one or two shocks.
Rebound needs to be under good control when launching.
Sprung weight for rear shocks on a motorcycle is nil until the rider sits down.
The longer the stretch the more the increase in spring rate.
Then the lean angle of the shock increases the spring rate.
The position of my shocks now is not much different than stock.
Do I sound like I'm learning something here ?!?!?!

I'm going to need to balance between ride ability and street fighter when the shocks are installed, and then a kidney belt when strutted :ambivalence:
Probably going to work from the softer side. Need to get the kinks worked out of this build as I go.

 

[unfocused]

Period looking drag bike with struts makes sense....will look trick with the right bodywork.

Thanks.

Nice build.
I looked at everything and wrestled with the idea but 2 shocks won me over.
Trust me when I say I had the mono mocked up.
Old school for an old fart like meself LOL

 

[unfocused]

Thought I'd share another pic since someone asked about spring rates and shocks LOL

This is the day I bought her. Not running, chain banjo string tight and rear brakes partially locked...
Found bad coils first
fuel petcock
then carbs
then brakes
all sorts of who did this sh%t ???

then the cam cap popped off of cylinders 1/2 exhaust cam...
...this is how it started LOL

I still have the fairing somewhere.

 

[Guest]

A tip: if you like the look of 3 spoke GSXR rear wheels like the one in your pic (02 GSXR 600/750 wheel I'm guessing?) you may find it tough to get a proper true chain run with that wheel even with an offset front sprocket because it's too wide at the hub. One solution is to use a 2006/2007 5.5x17" GSXR 600/750 rear wheel which is about 10mm narrower at the hub than the 02 wheel and has the same size axle/brake rotor diameter. Then use a 5/8" 520 offset front sprocket to get the chain run straight. You may have to get wheel spacers made up to get everything lined up.

 

[unfocused]

A tip: if you like the look of 3 spoke GSXR rear wheels like the one in your pic (02 GSXR 600/750 wheel I'm guessing?) you may find it tough to get a proper true chain run with that wheel even with an offset front sprocket because it's too wide at the hub. One solution is to use a 2006/2007 5.5x17" GSXR 600/750 rear wheel which is about 10mm narrower at the hub than the 02 wheel and has the same size axle/brake rotor diameter. Then use a 5/8" 520 offset front sprocket to get the chain run straight. You may have to get wheel spacers made up to get everything lined up.

Thank You.
which year rotor mount did you use? '06/07?
Yes on the wheels.
There is a lot on this subject floating around the forums. The lengths people have gone to make it true amazes me.
Funny thing is quality control in the 70's wasn't shall we say, evident lol
So as you know things will have to be adjusted for every frame with the parts being used.
I have spacers (commercial lawn mower spindle washers/spacers fit perfect) and have set it up with the sprocket strong to the outside like yours.
Lined up pretty good.
But nothing is bolted down yet so changes are to be made...!!!

 

[Steve]

You would ask me about that LMAO.

Just wanted to make sure that you knew it was an item that needed to be addressed. :encouragement:

Right now im leaning towards an 11"~12" shock [natural ride height] with with somewhere around a 6-700lbs spring, 7" or 8" long.
How far off em I ??? LOL

Couldn't tell you any dimensions without being there.

The longer the stretch the more the increase in spring rate.
Then the lean angle of the shock increases the spring rate.
The position of my shocks now is not much different than stock.

The fact that the position is not much different makes it a lot easier. :-k
1. Measure the distance from the swingarm pivot to the stock axle location.
2. Measure the distance from the swingarm pivot to the new axle location.
3. Divide the second measurement by the first.
4. Find the stock spring rate on a suspension vendor's site.
5. Multiply the spring rate by the answer to #3, you have a decent starting spring rate.

.

 

[Guest]

Thank You.
which year rotor mount did you use? '06/07?

Rear caliper bracket on mine is from an 05/06 GSXR 1000, same as the swingarm. Since you have what looks to be an extended 02 GSXR 600/750 swingarm, you should be able to use the stock caliper bracket, the 06 GSXR 600 wheel with its 220 mm diameter rear rotor (same as the 02), and then fab up a custom torque arm. You'll need to center the wheel in the frame first, measure to find the spacers needed to keep it in that position and then measure how much front sprocket offset you need. From my experience the max offset you can run in a GS frame is about 5/8" even with a 520 chain before the chain rubs the inside of the frame.

Yes on the wheels.
There is a lot on this subject floating around the forums. The lengths people have gone to make it true amazes me.
Funny thing is quality control in the 70's wasn't shall we say, evident lol
So as you know things will have to be adjusted for every frame with the parts being used.

True story. There's a general recipe for these kind of mods but every bike is slightly different.

I have spacers (commercial lawn mower spindle washers/spacers fit perfect) and have set it up with the sprocket strong to the outside like yours.
Lined up pretty good.
But nothing is bolted down yet so changes are to be made...!!!

If you need an offset front sprocket, give PBI Sprockets in Oregon a ring and ask for Randy. Great machinist who can make any size offset front sprocket you need including the 520 I use.

 

[unfocused]

Wonderful and thank you for the information.

I will put it to good use.

I'm not there yet and I'll add more photos and updates as the build moves along.
Steer bearings are showing up Thursday so this weekend is getting the front fascia in place

Goal is to safely ride it to Bike Week 2020 with my buddy on his '72 750 Commando.
His is on the lift and as you can see, we both have a steep goal LOL

 

[unfocused]

I've built plenty of drag race cars in my time.
Very few race bikes but several fast runners.

Never had to tuned the suspension on crotch rockets but I've read enough in the past years to be understanding of the process.
Now I am into processing the data I've amassed and apply it to this build...
Your information makes sense and just running numbers through my head and it's working.

I am looking at everything and making sure it's right. The days of farm built hot rods aren't over but this is going to be used on the streets so safety is paramount.

FYI:
I've looked over your valve spreadsheet and can't wait to use it. I've yet to touch the 750 head as the 1000cc mill jumped into my lap.


Thanks for that!!!

 

[unfocused]

Spent my weekend installing fork conversion bearings so those 2002 GSXR USD's would play nicely in the '77 GS750B frame. I couldn't be any happier. The only way it was going to be any easier to install those forks, was to have someone else do it LOL...

Now the steer stops, stabilizer, brake hose connector... let's not forget the headlight, turn signals, and all that damn '77 wiring... ugh.
All the brake hardware, light brackets and more are on there way. Thankfully so is a 4 day holiday

 

[unfocused]

Here she is staged, so I could see what lock to lock is going to look like and engineer a replacement... OK so my mind is wondering around the subject lol.

Did realize after staging her that the rear shock length is going to change drastically. Good thing for drive chain/swing arm.
Still have decent room for the header.