progressive springs

[AOD]

According to the Progressive Installation Manual the adjustable fork caps provide plenty of pre-load. I'm not even at the maximum position.

Cool.

 

[bucketsofgs1000]

Now the question after reading all this is: are progressive springs a better bargain than installing a used GSXR front end? Or is the GSXR front end going to make ANOTHER world of difference over the progressive springs. Just a thought...I have no idea either way on this one.

 

[mcycle-nut]

I found that putting Progressive springs in the forks, and Progressive shocks and springs on the rear of my 750 made a night and day difference. Because of that, I put fork springs in my EZ. It firmed up the front end substaintialy. I didn't use any air. Can't remember the oil viscosity. :-k

 

[bwringer]

Now the question after reading all this is: are progressive springs a better bargain than installing a used GSXR front end? Or is the GSXR front end going to make ANOTHER world of difference over the progressive springs. Just a thought...I have no idea either way on this one.

I would hazard a guess that a GS is a heckuva lot heavier than a GSXR, so you would need to dig up a heavier spring rate and fine-tune preload with spacers. Just guessing, though. I think the GSXR forks would be somewhat shorter, too, so that could create a lot of problems.

I do know some folks have had success with transplanting forks from a Bandit, which is a bike closer in weight and mission to a GS. However, later/larger model GSXR forks would have the yummy adjustability features, and some models even have the coveted upside-down forks.

Looking at it purely from a time/trouble/money standpoint, I would have to say that you're best off to optimize the existing suspension (don't forget good shocks on the rear) and spend your money and time on interesting roads learning to be a better rider.

Even with zooty modern forks in place, remember that the frame is still a relic from the '80s. With good springs in place and some attention to fine-tuning preload and fork oil, the fork is definitely not the weak point in GS handling.

On a GS, frame and swingarm flex tends to define the outer edge of handling more than any other factor, and it's the most difficult to do anything about. You're stuck with either bracing the frame (messy, difficult, and heavy) or reducing weight (difficult to do beyond a certain point). It's probably easier to eat nothing but lettuce and ice cubes for six months and reduce the load the bike has to haul around... :roll: :roll:

 

[Joe Nardy]

I agree with bwringer here to a point. But the fact remains that the GSXR forks are newer and probably cartridge-type rather than damper rod types. This is a huge step forward. You can't even compare the two. Of course, you'd have to tune the GSXR forks properly but once set up you'd have a better front suspension than you'd ever get from damper rod forks.

Thanks,
Joe

 

[bwringer]

I agree with bwringer here to a point. But the fact remains that the GSXR forks are newer and probably cartridge-type rather than damper rod types. This is a huge step forward. You can't even compare the two. Of course, you'd have to tune the GSXR forks properly but once set up you'd have a better front suspension than you'd ever get from damper rod forks.

Thanks,
Joe

Well said. I guess everyone has to define the cost/benefit equation for themselves. If we only did what made sense, we'd all be driving beige electric Volvos.

If you look at it another way, modern cartridge forks - PROPERLY TUNED - would certainly help you make the most of the ancient frame. You couldn't just slap 'em on there and go riding. And you'd need to at least upgrade the rear wheel and suspension to handle matching modern rubber.

I'd love to have some damping adjustability (compression and rebound both, please) -- messing with fork oil weights is crude and approximate in a damper rod fork. And greater stiffness, and external preload adjusters, and modern brick wall brakes, and wider wheels with modern rubber, and... :twisted: :twisted: :twisted:

 

[earlfor]

Yeah, I've thought about the whole proposition and on top of it all, I figure even if I do upgrade to a modern front and rear, rims, tires, etc and the handling is improved, the bottom line (to me anyway) is I dont have an 1150 anymore. I'm left with a mutt of a bike that has no lineage or character. For me, a lot of the attraction of the 1150 is what it is. I've pretty much decided to keep it stock and improve as that will allow.

Earl

I'd love to have some damping adjustability (compression and rebound both, please) -- messing with fork oil weights is crude and approximate in a damper rod fork. And greater stiffness, and external preload adjusters, and modern brick wall brakes, and wider wheels with modern rubber, and... :twisted: :twisted: :twisted:

 

[Joe Nardy]

Another very important thing Brian referred to is matching, or balancing the front and rear suspension. My 1100 forks have Progressive springs, new bushings, and fresh fork oil. My rear shocks are the originals and don't really do much more than keep the springs in place. While I can adjust my forks to be nice and firm the bike actually handles better with them set to their softest settings because the bike has better suspension balance that way. I plan on getting new shocks this winter and possibly Race Tech cartridge emulators for the forks. So next year I can firm both ends up and really enjoy the ride. I bought the cartridge emulators last year but Race Tech's website was incorrect and the emulators did not fit my forks. Brando just had his done and has the correct Race Tech part number: http://www.thegsresources.com/_forum/viewtopic.php?p=426731&highlight=#426731

At some point I feel it becomes futile to make drastic changes to an older bike. While I appreciate the fabrication skills and ingenuity of folks who do this I feel you'd be better off buying a newer bike.

Thanks,
Joe

 

[AOD]

Joe, I agree with you that at some point you're just polishing a turd, so to speak. I admire those that have installed Bandit or GSXR forks and swingarms on the older GS bikes, but it's not really a GS then anymore to me. New technology is so much better and it's available to us all.

Spending a little bit of money to improve the basic handling of the bike is well worth it though, but it's not going to out corner a GSXR ever.

~Adam

 

[AOD]

Post revival / update:

I received my progressive springs and fork oil from CRC2 last week and I finally got to start on it yesterday. I printed out the good help from this thread for reference.

I must say, the spring cap screws are PITA to remove. My 12 point socket was chewing up the bolt head on the caps. I managed to get one side loose, but the other was turning in the socket. I borrowed a 6 point socket (22mm) from some friends with the hope that I didn't screw it up too bad...

I'll try and take pictures along the way.

~Adam

 

[earlfor]

Yep, a six point socket is the only way to go. I found out the hard way too.

Earl

Post revival / update:
My 12 point socket was chewing up the bolt head on the caps. I managed to get one side loose, but the other was turning in the socket. I borrowed a 6 point socket (22mm) from some friends with the hope that I didn't screw it up too bad...

I'll try and take pictures along the way.

~Adam

 

[bwringer]

Brian W., I take it your 850 didn't have preload adjustment on the front?

~Adam

Correct. IIRC, only a few later big bore models had preload adjusters on the forks.

As far as preload spacer length, you just have to experiment -- the forks on your new(er) bike are very different from the forks on earlier bikes. I simply started with the recommendation in the package and added about 3/4 inch, purely a WAG (wild-a**ed guess) based on my higher-than-average mass and preferred velocity. I used some hunks of aluminum pipe I had lying around, and made sure to carefully trim and grind the spacers to the exact same length and clean up any burrs before installing. A few years later, I decided to make new spacers that were about 1/2 inch longer, and that seems about perfect.

I think my preference for heavier fork oil (augmented to be even thicker with motor honey) has more to do with compensating for 70,000 miles of internal wear from bashing around on crappy back roads. It's what works for my bike, anyway.

Those of you with pampered, low-mileage museum pieces likely would be fine with straight 10W or 15W fork oil to taste.

 

[bwringer]

Spending a little bit of money to improve the basic handling of the bike is well worth it though, but it's not going to out corner a GSXR ever.

~Adam

You betcha. Of course, the average highly experienced and skilled GS rider is going to outcorner the average t-shirt-and-flipflops-wearing GSXR squid any day.

Just call me a proud Turd Polisher...

 

[AOD]

hehe!

I forgot to mention that Progressive did include about 8 inches of PVC tube in the box with my new springs...so that's nice of them! I have the preload adjusters though, so I don't think I'll need it.

I got a few 22mm 6-point sockets from some co-workers now. Hoping to find time later this week to work on it, but this weekend already looks busy...

~Adam

 

[Sandy]

I put Progressive front springs in my 79 GS1000 this past summer and they made a tremendous difference over the old bagged out stockers. As the springs stuck out about 3/4" and the caps compress the spring 1" I didn't use any spacers, they didn't come with any either. I started with 15W fork oil and added the stock amount as at the time there where no instructions telling me otherwise. I'll have to look into that some more. I'm still at the point of fine tuning it a little but they do seem to be really close to what I like. Maybe I'll try 20W fork oil as they seem a little soft and I am a little porky. A good way to fine tune the front suspension is to put a tie wrap around each fork leg, set the right one at where the maximum compression is and use left one to measure suspension travel. The left one I find easier to slide down the fork while I'm riding. Go for a ride and you can see how travel you are using under different riding condition and also check to make sure you not coming too close to bottoming out under extreme braking, try this just using the front brake. The picture below shows this set up and how much travel I used after quite a brisk ride on fairly rough paved road with out testing the braking. I need to firm it up slightly and I think the fork oil will do that, if that makes it harsher than I think a small spacer might be in order. Oh yeah, no air, I find that far to inconsistent. The tie wraps are visible in the picture below.

 

[AOD]

Welp, good news, things shaped up really well this weekend. I started working around 8 PM on Friday in the garage, finished up for the night around midnight even after a 30 minute phone call with Joe Nardy!

Some interesting notes. The 83 GS1100 with air suspenion has adjustable preload of about 1/2" total. Including the cap bolt itself and the adjustment you have roughly 1.5" of preload. The air suspension o-ring spacer is just over .6" thick, which makes your grand total of STOCK preload just over 2".

It is different on other bikes, but I wanted to share my findings at least.

A few things I learned. I had to remove the '84 GS1150 oil cooler to get the fork all the way compressed. Also, when you have it compressed and add fork oil, you need to compress the forks a few times to get it circulated THEN do the oil level measurement.

I used a fork oil level of 7.7 inches, probably on the high side, give or take. 8-ounces or 1-cup of fluid translated to roughly 8 inches of fork oil height.

The progressive springs are MUCH beefier than the stock springs if you compare them, but as for length they're only 1/2" longer. I sent my preload in the "2" position (of "4" total) for now and the front end is soooooo much stiffer than before when I bounce it.

I also removed the anti-dive lines as Joe instructed above. Finding 10M fine pitch (100) bolts was a challenge, currently they're a little too long, but it works.

I took it for a quick ride (it was kind of chilly and I have no plates on it) and it's 500x times more confident in the turns now. Instead of the wallowy feeling it had before, it tracks a lot better. Handling is now up to where it was on my old 550 that was dialed in!

~Adam

 

[wrench]

This is a great thread guys, i'm learning lots, thanks a bunch

 

[Joe Nardy]

Welp, good news, things shaped up really well this weekend. I started working around 8 PM on Friday in the garage, finished up for the night around midnight even after a 30 minute phone call with Joe Nardy!

Some interesting notes. The 83 GS1100 with air suspenion has adjustable preload of about 1/2" total. Including the cap bolt itself and the adjustment you have roughly 1.5" of preload. The air suspension o-ring spacer is just over .6" thick, which makes your grand total of STOCK preload just over 2".

It is different on other bikes, but I wanted to share my findings at least.

A few things I learned. I had to remove the '84 GS1150 oil cooler to get the fork all the way compressed. Also, when you have it compressed and add fork oil, you need to compress the forks a few times to get it circulated THEN do the oil level measurement.

I used a fork oil level of 7.7 inches, probably on the high side, give or take. 8-ounces or 1-cup of fluid translated to roughly 8 inches of fork oil height.

The progressive springs are MUCH beefier than the stock springs if you compare them, but as for length they're only 1/2" longer. I sent my preload in the "2" position (of "4" total) for now and the front end is soooooo much stiffer than before when I bounce it.

I also removed the anti-dive lines as Joe instructed above. Finding 10M fine pitch (100) bolts was a challenge, currently they're a little too long, but it works.

I took it for a quick ride (it was kind of chilly and I have no plates on it) and it's 500x times more confident in the turns now. Instead of the wallowy feeling it had before, it tracks a lot better. Handling is now up to where it was on my old 550 that was dialed in!

~Adam

Adam,

Did you measure the amount of static fork sag after installing the new springs? The forks should compress roughly an inch from fully extended with you sitting on the bike in the riding position. You can measure this using the tie-wrap method Sandy mentioned above. It helps to have a friend holding the bike steady for you.

Now you need some good aftermarket shocks to balance the front and rear suspension.

Do you think it would be easy to fabricate a bracket to move the oil cooler out of the way of the fender? I personally think an oil cooler is one of the nicest things you can do for your engine.

Thanks,
Joe

 

[Boondocks]

Yeah, I've thought about the whole proposition and on top of it all, I figure even if I do upgrade to a modern front and rear, rims, tires, etc and the handling is improved, the bottom line (to me anyway) is I dont have an 1150 anymore. I'm left with a mutt of a bike that has no lineage or character. For me, a lot of the attraction of the 1150 is what it is. I've pretty much decided to keep it stock and improve as that will allow.

Earl

Well said.

It seems that more and more "mutts" are being created, changing the look and essential history and personality of a great series of GS motorcycles. The original bikes are becoming rare, partially because of conversion to Frankencycles.:-? I have nothing against this per se, if starting with incomplete parts. For instance, if I had just an engine it would be fun to build a high performace motorcycle around it. But with a complete classic bike, I would tweak the weak spots with improved aftermarket replacements and retain the stock look and feel.

 

[AOD]

Joe, I could just reinstall the oil cooler if I wanted to keep it, however I run only synthetic oil so I'm not terribly worried. The old 550 did well with no oil cooler...so I think it will be okay.

I didn't get a chance to measure the static sag yet. I will do the tie strap method as mentioned, I just didn't get to it. I left the preload adjustment covers off for the time being, so I can dial it in.

Next on the list is rear shocks...as you suggested.

~Adam