Front Forks

[Guest KeS]

 

The biggest problem was getting the stock spring off.

I used two ratcheting tie downs to compress the spring. It took over an hour of figuring out that I need to loop the strap a couple times to get the block and tackle effect going.

The guy on our forum who recommended straps attached pictures of the blood on the shock from his hands. So be careful!!!

 

I'm confused. How much preload is that stock Sachs spring running?! Mine has an inch or so of threads left, you're saying that after you back off the collars all the way, there's still preload left in the spring??

 

On another note, since this is a fork thread - does anyone have a good link to the disassembly/reassembly process for the Marzocchis? I have a set of fork springs coming in, but all I remember about taking forks apart is that I hate it (been on Telelever front ends for the last couple of years).

 

KeS

[Guest ratchethack]

KeS, I'm not sure what Dave was referring to back when he posted that.

 

WRT the Marz fork, with the front wheel of the floor, there's not very much preload left in the springs to be much of a concern, assuming you have reasonable length spacers. You can easily overcome it by hand - enough to thread the caps back in. The only procedure I've ever seen on the Marz 40 mm USD fork is in the Guzzi shop manual. While it ain't the best shop manual I've seen, it's a far cry better than naught. . . .

 

If you ignore changing out fork oil (evidently most do ), or you simply don't need to, you can easily replace the fork springs in about 10 minutes. It's all pretty straightforward.

 

With the bike on the stand and front wheel off the floor,

 

1. Set comp & rebound adjusters full left adjustment (beats me, but that's wot the manual calls for)

2. Back out the fork caps and block up the front wheel as high as it will go, which will raise the cartridge assemblies in the stanchions.

3. Crack off the blue anodized jam nuts from the fork caps and remove the caps.

4. Measure the remaining thread on the cartridge assembly rods (I think it's 22mm)

5. Remove the blue jam nuts - or if y'er tough enuff just compress the springs and slip the spring retainers out.

6. Remove springs, cut new spacers, replace springs, or do whatever tickles y'er fancy.

7. I'd make certain to set the air gap to 100 mm, or if y'er smarter than "generic", go slightly more or less than this, but make sure to get them equal with the forks fully compressed.

8. Re-install the whole mess the way it came out, using y'er original thread measurement settings for the blue anodized jam nuts.

 

. . . . . and Bob's Y'er Mother's Brother.

[Guest KeS]

KeS, I'm not sure what Dave was referring to back when he posted that.

 

WRT the Marz fork, with the front wheel of the floor, there's not very much preload left in the springs to be much of a concern, assuming you have reasonable length spacers. You can easily overcome it by hand - enough to thread the caps back in. The only procedure I've ever seen on the Marz 40 mm USD fork is in the Guzzi shop manual. While it ain't the best shop manual I've seen, it's a far cry better than naught. . . .

 

If you ignore changing out fork oil (evidently most do ), or you simply don't need to, you can easily replace the fork springs in about 10 minutes. It's all pretty straightforward.

 

With the bike on the stand and front wheel off the floor,

 

1. Set comp & rebound adjusters full left adjustment (beats me, but that's wot the manual calls for)

2. Back out the fork caps and block up the front wheel as high as it will go, which will raise the cartridge assemblies in the stanchions.

3. Crack off the blue anodized jam nuts from the fork caps and remove the caps.

4. Measure the remaining thread on the cartridge assembly rods (I think it's 22mm)

5. Remove the blue jam nuts - or if y'er tough enuff just compress the springs and slip the spring retainers out.

6. Remove springs, cut new spacers, replace springs, or do whatever tickles y'er fancy.

7. I'd make certain to set the air gap to 100 mm, or if y'er smarter than "generic", go slightly more or less than this, but make sure to get them equal with the forks fully compressed.

8. Re-install the whole mess the way it came out, using y'er original thread measurement settings for the blue anodized jam nuts.

 

. . . . . and Bob's Y'er Mother's Brother.

 

Thanks for the instructions, that's enough to get me in trouble with the fork!

 

The quote about the Sachs preload was about the rear shock (mixed post). It seemed like he was saying that you had to use spring compressors to assemble/disassemble the spring from the shock. I was - er, shocked to hear that, as in my experience with other car/bike coilovers you can generally remove all preload by just backing the collars off, and the Sachs looks like it has at least an inch of thread left on the topside. I'd be amazed if the stock spring was running THAT much preload.

 

KeS

[dlaing]

Thanks for the instructions, that's enough to get me in trouble with the fork!

 

The quote about the Sachs preload was about the rear shock (mixed post). It seemed like he was saying that you had to use spring compressors to assemble/disassemble the spring from the shock. I was - er, shocked to hear that, as in my experience with other car/bike coilovers you can generally remove all preload by just backing the collars off, and the Sachs looks like it has at least an inch of thread left on the topside. I'd be amazed if the stock spring was running THAT much preload.

 

KeS

Yes we are talking shock and not fork, and yep, with the preload backed off the collars are too tight to get off by hand, so I did what I mentioned, compressing the spring before removing the clollars.

When I replaced it with the HyperCoil spring, I ordered a spring that was short enough to slip under the collars without using a spring compressor and then added appropriate pre-load.

[Guest KeS]

Yes we are talking shock and not fork, and yep, with the preload backed off the collars are too tight to get off by hand, so I did what I mentioned, compressing the spring before removing the clollars.

When I replaced it with the HyperCoil spring, I ordered a spring that was short enough to slip under the collars without using a spring compressor and then added appropriate pre-load.

 

Thanks! Do you remember what the length was? I was hearing 6" x 2.25 diameter being thrown around - I was going to order an Eibach from my car suspension vendor just for the pretty red color.

 

 

KeS

[dlaing]

Thanks! Do you remember what the length was? I was hearing 6" x 2.25 diameter being thrown around - I was going to order an Eibach from my car suspension vendor just for the pretty red color.

KeS

Yep, that is the size I got.

See details here

http://www.v11lemans.com/forums/index.php?...mp;hl=HyperCoil

The 2.25" is just a little looser fit around the seats than the OEM Sachs spring.

Meaning the OEM Sachs Spring had a tighter Inner Diameter...probably 55mm vs. 2.25"

But it seems to work fine and stay centered on the seats.

I wish I had gotten a RED spring

[Guest KeS]

Yep, that is the size I got.

See details here

http://www.v11lemans.com/forums/index.php?...mp;hl=HyperCoil

The 2.25" is just a little looser fit around the seats than the OEM Sachs spring.

Meaning the OEM Sachs Spring had a tighter Inner Diameter...probably 55mm vs. 2.25"

But it seems to work fine and stay centered on the seats.

I wish I had gotten a RED spring

 

Well, I have a whole stack of 450 - 650 lb/in RED 2.5" Eibach springs in lengths from 8-10" on the shelf here! That's what you get when trying to dial out rear wheel lift on an Evo 8...

 

Worse, I have a brand new CBR954 shock here that's eye-to-eye almost identical to the Sachs, but the spring rates are way off (almost 800lb/in) from what I see. Oh well - got the Sachs unit off the bike during halftime tonight, anyway.

 

KeS

[Guest KeS]

The biggest problem was getting the stock spring off.

I used two ratcheting tie downs to compress the spring. It took over an hour of figuring out that I need to loop the strap a couple times to get the block and tackle effect going.

The guy on our forum who recommended straps attached pictures of the blood on the shock from his hands. So be careful!!!

If I were to do it again, I would get my fattest friend to sit on the bike while I tightened the straps, and then remove the shock, and then the spring.

A strap around the wheel and saddle could replace a fat friend.

Aside from overcoming the force of the spring, you will have to balance the force with the straps to keep the spring straight.

I probably also made the mistake of setting the pre-load to minimum instead of maximum, before using the straps.

 

I won't mention here that I was able to slide a medium screwdriver through the shaft slot and over the spacer, and lever the spring down enough to remove the spacer in about 20 seconds - because that might depress you and I wouldn't want to do that after you've been so helpful in sharing your experience. But others might want to try that before getting jiggy with spring compressors and tiedowns.

 

KeS

[Dan M]

After admittedly getting a little wacky on springs in that thread , I finally ordered new Wilbers progressives which came in last week, but can't comment, as I haven't put 'em in yet.

 

Good luck!

 

 

Ratchet,

 

When you get 'round to installing your progressives, please post the length of preload spacer you end up with. I did mine in the spring and remember cutting four or more sets of spacers until I got the sag in the proper range albeit at the soft end of the range. I'd have to pull them and measure to be sure, (which is likely less time consuming than finding my notes) but think ended up adding about 19mm of preload. I'm about your size - 180lbs + gear, and got Wilbers progressives from Todd E. I wonder how much spacer can go in without defeating the progressive quality of the spring.

They work great and are far & away better than stock, but I tend to get a little nuts with dialing things in "just right"

[Guest ratchethack]

Ratchet,

 

When you get 'round to installing your progressives, please post the length of preload spacer you end up with. I did mine in the spring and remember cutting four or more sets of spacers until I got the sag in the proper range albeit at the soft end of the range. I'd have to pull them and measure to be sure, (which is likely less time consuming than finding my notes) but think ended up adding about 19mm of preload. I'm about your size - 180lbs + gear, and got Wilbers progressives from Todd E. I wonder how much spacer can go in without defeating the progressive quality of the spring.

They work great and are far & away better than stock, but I tend to get a little nuts with dialing things in "just right"

Dan, my last post on the Wilbers progressive fork springs in this thread (#4 post above) was in the middle of last summer, so I've had 'em installed and dialed-in for well over a year now. Within the first week I had cut new spacers, tried a few different lengths, measuring sags in between, and I'm pretty sure I ended up with 5-6 mm shorter than stock to get the laden and unladen sags exactly where I wanted 'em. In any case, the stock length spacers weren't too far off. Then I set and tested the air gap on the road by hitting square-edged bumps while howling the front tire with the brake until I thought it was as good as I'm ever gonna get it -- 100 mm was just right -- no bottoming, but used up 115 mm of the available 120 mm fork travel. In my hardest mountain riding, I use about 110 mm. I posted all this here somewhere a year back, including the exact spacer length I ended up with, but it'd take me too long to find it now.

 

You won't defeat the progressive nature of the springs with any preload setting with the correct match of rate to load. They're gonna be progressive until they stop continuing to coil-bind, and this takes considerable load on the spring to achieve -- far beyond the operational limit of the springs. This can't happen unless you've gone beyond the bottom-out limit of the forks.

 

I've been dialing in the new Wilbers 641 shock lately and need to re-visit my fork sags and I'll be taking fork measurements and matching up fore and aft sags. If y'er interested, I'll give 'em a year-plus checkup measurement on the fork and re-post the sags here. I've been extremely pleased with the match of the fork springs to my weight and the way I ride. I don't think there's any way to have a better match.

[Alex-Corsa]

-->

The bike has the Marazocchi with no preload adjustment.

Currently there is way to much movement on the bike, I have the compression dampning one click away from full. and the rebound around 3/4

 

Is there a recommended sring for these forks or is it a matter of shimming.

 

Thanks

Marc

 

When was the last time you have put fresh oil in the forks?

[Dan M]

Dan, my last post on the Wilbers progressive fork springs in this thread (#4 post above) was in the middle of last summer, so I've had 'em installed and dialed-in for well over a year now. Within the first week I had cut new spacers, tried a few different lengths, measuring sags in between, and I'm pretty sure I ended up with 5-6 mm shorter than stock to get the laden and unladen sags exactly where I wanted 'em. In any case, the stock length spacers weren't too far off. Then I set and tested the air gap on the road by hitting square-edged bumps while howling the front tire with the brake until I thought it was as good as I'm ever gonna get it -- 100 mm was just right -- no bottoming, but used up 115 mm of the available 120 mm fork travel. In my hardest mountain riding, I use about 110 mm. I posted all this here somewhere a year back, including the exact spacer length I ended up with, but it'd take me too long to find it now.

 

You won't defeat the progressive nature of the springs with any preload setting with the correct match of rate to load. They're gonna be progressive until they stop coil-binding, and this takes considerable load on the spring to achieve -- I believe this is quite a ways past laden sag.

 

I've been dialing in the new Wilbers 641 shock lately and need to re-visit my fork sags and I'll be taking fork measurements and matching up fore and aft sags. If y'er interested, I'll give 'em a year-plus checkup measurement on the fork and re-post the sags here. I've been extremely pleased with the match of the fork springs to my weight and the way I ride. I don't think there's any way to have a better match.

 

 

Sorry, should've looked at the dates

 

Evidently we have different rate springs. When I ordered from Todd he asked my weight and selected the springs. I felt like I was adding too much preload to get proper sag. (it would be interesting to know how much compression it takes to bind all of the close coils, maybe next time it is apart I'll get some threaded rod and experiment) I suppose if both laden & unladen sag are within the limits, spring rate is OK & I should stop obsessing.

thanks for the info though...

[Guest ratchethack]

Evidently we have different rate springs. . . . .I felt like I was adding too much preload to get proper sag. (it would be interesting to know how much compression it takes to bind all of the close coils, maybe next time it is apart I'll get some threaded rod and experiment) I suppose if both laden & unladen sag are within the limits, spring rate is OK & I should stop obsessing.

thanks for the info though...

Dan, if y'er gonna go through the effort to do this, it's always been my philosophy that you might as well get it right. Nothing wrong with this kinda "obsession". That's wot we got Tech Forums for.

 

I think of it this way: The Guzzi is WELL WORTH the effort.

 

Some of us actually enjoy all the twiddlin' and fettlin'. Come on admit it -- you know you enjoy it too.

 

Besides all that - it seems to REALLY IRRITATE all the guys 'round here who seem to be carrying around a tremendous sense of GUILT for neglecting their Guzzis by not doing it themselves. . .

 

Like you said, if you have both laden and unladen sags in your target range, this is what confirms a proper spring rate.

 

If you think about the nature of the progressively wound spring, the "tight" coils get less tight until they are the same as the rest of the spring. Logically, this would mean that as the spring compresses, the last of the "tight" coils to coil bind won't fully bind until the entire spring is close to coil-binding, and this ain't ever gonna happen in y'er fork or anyone else's. Capiche?

 

I'm thinking we must have different springs also because you had to add nearly 2 cm preload vs. my taking off 5-6 mm, though we seem to weigh the same and we both got Todd's recommendation.

 

EDIT: I just noticed you have an '02 LM. I believe this may be a different fork than my 40 mm Marz USD. This would explain the differences.

 

FWIW, the P/N on my springs (Bestellnr.) is 600-062-01.

[Dan M]

Dan, if y'er gonna go through the effort to do this, it's always been my philosophy that you might as well get it right. Nothing wrong with this kinda "obsession". That's wot we got Tech Forums for.

 

Agreed, I'm all about that. I just need to take a step back occasionally and weigh time & effort vs net result. I've been known to spend a bit of time "fine tuning"

 

I think of it this way: The Guzzi is WELL WORTH the effort.

 

Absolutely!

[Guest ratchethack]

Dan, I just checked. FYI, I put in 105 mm spacers to replace the stock 110 mm spacers. I also tried 100 mm spacers. Again, I think your forks must be different than mine.

 

The stock 110 mm spacers gave unladen sag of 25 mm, laden 38 mm with the Wilbers fork springs.

 

This translates to UNL 21% and L 32% sags.

 

I've been experimenting with fork height lately. I'm always struck by how complex chassis tuning actually is. When you make one change to chassis geometry, it makes changes that affect the way you need to set and then re-set other adjustments. And so it goes. . . . .

 

I'll be trying the stock spacers again to see how each set works on the road with the new Wilbers shock.