Scrambler build - looking to increase clearance - question on forks/ springs

[Guest]

Good Evening again gents,

I've got an 81 GS850G (my first/ original one) and I've decided to wander down a scrambler build/ route with it.


Whats 'the best' way to increase the ride height and maintaining the overall geometry of the bike? (New forks? which ones? new rear springs? which ones? etc etc)

Whats the cheapest way to increase the ride height without doing long term damage to the bike? (heavier shock oil or more pressure in the forks etc etc?)

Not looking to take this bike on long rides - maybe a little brap brapping around with my buddy on an afternoon with his beastly 90s Savage

I'm 6'3 and about 225lbs if that has any bearing on all of this.

Did a bit of looking around and thinking about reaching out to Sonic Springs - but curious if there's other stuff I'm not thinking of.

Thanks as always for your opinions, guidance, assistance and help!

 

[Steve]

Please don't raise the 850. :-k

Changing the ride height on a shafty changes the angle of the u-joint in the driveshaft. That is not a constant-velocity joint, so an increased angle will increase the cyclic speed changes, which will aggravate the wear on the splines.

If your '81 bike is an early-production bike and still has the original splines, they might handle it, but if you have a late-production bike and through the '82 models, you will have a softer spline which is already in jeopardy, no sense it making it worse.

One other thing to consider: a "scrambler" is supposed to be a light, agile bike that you might occasionally take into the dirt. The 850 is the heaviest GS that was made, except for the 1100GK, which added fairing, saddlebags and trunk. If you want a "scrambler", start with a lighter bike. One that is chain-driven will make it even better.

.

 

[Rob S.]

One other thing to consider: a "scrambler" is supposed to be a light, agile bike that you might occasionally take into the dirt. The 850 is the heaviest GS that was made, except for the 1100GK, which added fairing, saddlebags and trunk. If you want a "scrambler", start with a lighter bike. One that is chain-driven will make it even better.

.

I thought so. I didn't even take into account the shaft. A very heavy shaft drive bike. Ugh.

 

[Guest]

Please don't raise the 850. :-k

Changing the ride height on a shafty changes the angle of the u-joint in the driveshaft. That is not a constant-velocity joint, so an increased angle will increase the cyclic speed changes, which will aggravate the wear on the splines.

.

And this is why I come here I didn't even think about the driveshaft.

I'll keep the geometry stock and just replace/ rebuild things as necessary. This is more of a wrenching/ build project than an effort to get the bike up and running (thats what my OTHER GS850 is for!!!)

Once I get going on the thing I'll be sure to get some good pics and updates for you guys here!

Thanks again for all the help!

 

[bwringer]

- Getting the bike's suspension sprung correctly will raise it up a fair bit. The flaccid stock fork and shock springs usually let both ends sag into the last 1/3 of their travel with a rider on board. The correct spring rates and preload can bring sag into the top 1/3 - 1/4 of total travel and improve handling and safety immensely in all conditions. Suspension travel at both ends is about 4 inches (100mm).

- You can safely go with 1/2" longer shocks on a GS shaftie, but that's it. Stock is 13 inches (330mm) eye-to-eye. Some models have a wee tab on the frame that limits the downward travel of the swingarm. You may need to grind this slightly to fit longer shocks.


And yeah, an 850 is a heavy, sleepy beast indeed off-pavement. That said, it works fine on gravel and reasonably hard surfaces, and tires with a little more tread to them do work a little better.

 

[tatu]

This was a bit of fun, revived over the lockdown period from a crusty corroded road bike, it's a '79 1000 purchased as a breaker ten years ago and left under bush but we don't break them anymore these days...As far as i know it hasn't run since '97. Fork tubes are standard L and rear shocks YSS. The engine has only been given a severe wire brushing, I've not looked at the points or shims though it did get new carb rubbers It's fast and a hoot to ride and I use it all the time I can.

 

[Guest]

- Getting the bike's suspension sprung correctly will raise it up a fair bit. The flaccid stock fork and shock springs usually let both ends sag into the last 1/3 of their travel with a rider on board. The correct spring rates and preload can bring sag into the top 1/3 - 1/4 of total travel and improve handling and safety immensely in all conditions. Suspension travel at both ends is about 4 inches (100mm).

- You can safely go with 1/2" longer shocks on a GS shaftie, but that's it. Stock is 13 inches (330mm) eye-to-eye. Some models have a wee tab on the frame that limits the downward travel of the swingarm. You may need to grind this slightly to fit longer shocks.

And yeah, an 850 is a heavy, sleepy beast indeed off-pavement. That said, it works fine on gravel and reasonably hard surfaces, and tires with a little more tread to them do work a little better.

Are the shocks available from Sonic Springs a good replacement for the stockers? They've got a few options - how will those options affect the front forks? Are there other/ better springs I should be looking at? What about for the rears? What should I be looking for?

 

[Guest]

This was a bit of fun, revived over the lockdown period from a crusty corroded road bike
View attachment 61461

This is gorgeous and the type of mod/ build I'm looking to do! Love the look and styling!

 

[bwringer]

Are the shocks available from Sonic Springs a good replacement for the stockers? They've got a few options - how will those options affect the front forks? Are there other/ better springs I should be looking at? What about for the rears? What should I be looking for?

Yes, Sonic straight-rate fork springs are excellent quality. Sonic Springs are on all my bikes.
http://sonicsprings.com/catalog/index.php

There's a calculator on the site where you figure out the correct spring rate based on your weight and the bike's weight. They come with instructions for measuring and cutting spacers to get the correct amount of preload.


This thread on rear shocks just popped up again today, and it's an excellent overview of the rear shock options available:
https://www.thegsresources.com/_forum/showthread.php?253261-Rear-shock-shopping

 

[Rob S.]

This is gorgeous and the type of mod/ build I'm looking to do! Love the look and styling!

Plus I bet someone who just noticed that front fender would be surprised at the sound. Does not sound like many scramblers.

I have Race-Tech springs in the forks of my 11E (pretty much the equivalent of Sonic). I was 165 lbs soaking wet, so I got .9 (.95?), should have or could have gone a step stiffer.