Penske Suspension Upgrade

Hi all,

So like a lot of the Guzzi faithful, I was drawn to the GRiSO because of the unique nature of the bike and the storied allure of Moto Guzzi.  Also, when comparing it to other “Heritage” bikes on the market, the value seemed like a no brainer. Big lumpy engine, fully adjustable suspension, adjustable levers, shaft drive, and the style… so much style. I never tire of looking at the GRiSO!  Those folks at Mandello del Lario really sculpted a beauty. I also calculated that since the GRiSO hasn’t changed much over the years, the chassis was well sorted. I couldn’t have been more wrong.

I picked up a leftover 2017 last October (‘18). Since then, I’ve clocked right around 1900 miles. The engine and gearbox have broken in beautifully, and has a great purr to it, even with the stock exhaust.
I’ve been lucky enough to have ridden dozens of bikes from all makes over the years. I can say the handling of this bike out of the box is probably one of the worst I’ve ever experienced. After an hour in the saddle on our 3rd world, neglected roadways, my arms hurt  and my spine was on fire. As it’s been well documented on this forum, the rear shock is woefully under-sprung, so you have to crank up the preload to get anything close to the correct range (I’m 205 lbs in full battle dress). The forks seemed to be just as bad, I cranked up the preload and backed out compression and rebound. After fiddling around, reading the forums, and trying several different settings, I became discouraged. A terrible thought entered my mind – did I make a huge mistake buying this bike? I bought the bike knowing it was quirky, but I wasn’t expecting an experience bordering on un-ridable.

**Mods Selection**
After some coffee and contemplation, I decided to keep the bike and go all in with suspension mods. I considered just buying some springs or even going for a Stelvio shock like others have done, but I felt like those are really just band-aids to the issues. I want a bike that handles well and that the wife would be willing to hop on and not risk a spine injury.
I reached out to the folks over at Penske Racing. 2 years ago they did a great job revalving my KTM dirtbike suspension, so I had faith they could deliver an improvement even with a niche bike like the GRiSO. Talking with Penske, they recommended a 20mm piston kit, new shim stacks, and heavier springs to go in the forks. [You must be registered and logged in to see this link.]
For the shock, they weren’t keen to work on the Sachs, so my option was to select a new Penske shock. This gave me pause because of the cost, but I figured that this would give me the best performance overall. I went with the 8975 inline, double adjustable. Inline, because the reservoir is internal and double because it’s compression and rebound adjustable. [You must be registered and logged in to see this link.] With my weight, they specked out an 850lb spring which is a big jump up from the stocker. I kept the length the same, as I didn’t really want it any taller.

**Shock Removal**
There seems to be various approaches to remove the rear shock and depending on how you are holding the bike, you have to deploy a different method. For me, I supported the bike under the oil pan using a couple of cut up fence posts and a 2x6. My floor jack did the lifting under the 2x6. As an extra measure of security, I dropped a couple of straps from the rafters to loop around the handlebars. This kept everything steady and allowed me to remove the front forks and rear shock quite easily. (the image shows an additional strap through the frame, but I removed it soon after the photo was taken) Once secured, I removed the left lateral plate (porkchop), passenger peg mount/muffler, and the right passenger peg support. This gave me access to the linkage, and top/bottom shock bolts. The shock came right out the left side of the bike, with minimal fuss. I had already greased the linkage when I first got the bike.

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**Fresh Suspension**
I was beyond excited the day my suspension came back from Penske and I immediately set about to reinstalling it. (You’re on your own for dinner kids!) I fitted up the forks, torqued everything to spec, and started to install the shock. The Penske shock is very compact and since there isn’t a horizontal reservoir, it had plenty of room for installation. My enthusiasm quickly tanked when I realized that they installed bushings on both sides of the clevis. Meaning my lower shock bolt had nothing to thread into. So, I pulled it off and sent it back to Penske for correction. A few days and emails later I got my shock back, this time with a threaded insert in the clevis. One other deviation from stock- Penske used a fine thread M10 insert (1.25) and the stock Guzzi bolt is coarse thread (1.50). I went and sourced a Class 10.9 M10x1.25x50 bolt. The 50 was a bit long, so I special ordered a 45mm. In the meantime, I ground down the 50 for clearance and finished the install. (I believe stock is a 47mm)
The lower clevis thing ultimately wasn’t a big deal, I knew there was going to be a learning curve since this was the first time Penske fitted up that model shock to this bike. I feel compelled to point out that Penske’s customer service is pretty awesome. In today’s world where customer service and competency is largely an afterthought, I was pleasantly surprised by the level of service I received. I’m sure for future orders they will have these details noted, so anyone ordering these will have smooth sailing.

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**The Ride**
With trepidation and excitement I swung my leg over and went for a rip. I tried to keep good mental notes. It’s hard not to psych yourself out after you just dropped a chunk of change to fix a problem that you feel shouldn’t be there in the first place, but I digress. The first thing I noticed was the stance of the bike was now balanced. Or more to the point, I realized how unbalanced/undersprung the bike was originally. This was masked in part because the preload was cranked up on the stock suspension, but now it is really evident.
The next thing I realized is that the bike didn’t require such a heavy steering input from the handlebars. I could now use my hips to steer the bike.  This translated into much improved turning and cornering. We don’t have a lot of curves around here, but in the few I could find, it would hold a clean line. Before it would want to run wide in a corner. The bike always did well in the sweepers, but round-abouts and tight radius corners were sketchy. The wallow that was present when leaned over has also been curtailed.
Under braking, the bike no longer dives or shifts bias as much.
Small bumps and road feedback is still there, which I suppose is going to be inherent with fix mounted bars. Medium bumps, potholes, frost heaves, and railroad tracks no longer send me digging for my kidney belt. Large bumps weren’t ever really a problem.
It still feels plenty sporty, with plenty of tactile feedback from the road. It’s never going to be a marshmallow, which is great, because that’s not what I wanted. And it will always be a bit touchy to clicker changes when compared to other bikes. I look forward to getting this bike in the mountains next spring to really lay into it and see what she can do.

**2-Up riding**
I didn’t do a ton 2-up riding on this bike, mainly because after the first outing, the missus refused to ride on it. But, I am very pleased to say that post-surgery, riding for two is much improved. She said that it no longer feels like she’s going to get thrown off the back. On the piloting side, steering and handling stayed predictable and smooth.  

**Summary**
As the season draws to a close, I am trying to sneak in as many miles as possible. I’m still riding with a hyper-sensitivity on how the suspension is performing. The goal is to have the suspension melt away into the larger overall riding experience, and just focus on the pleasure of the ride. I still have some tweaking to do, but I am confident that this was a good investment. There are a lot of options out there my fellow GRiSO riders and Penske is a good one.

My settings-
Forks
Height above TC: 4 rings
Preload: 11mm  showing, about 5 turns
Comp: 2
Reb: 2
free sag: 22mm
rider Sag: 42mm

Penske Shock
Comp: 24
Reb: 18
Free Sag: 10mm
Rider Sag: 25mm

Tire Pressure
Front 34lbs
Rear 36lbs

MGrider

Thanks for posting, I'm always interested in someone elses approach to how they improve the suspension to their liking.

Did you ship the forks out to Penske or did you work on them yourself ?

What weight fork springs did you go to ? 9.5 kg/mm or 1 kg/mm ?

Hopefully see you at the Guzzi rally in Zanesville next year to compare GRiSO's

@Nobleswood,
I sent my forks over to Penske (PA) for the work. I figured it's best to let the experts handle it when it comes to suspension.
I'm not sure which spring they chose, I'll reach out to them and see. I just gave them my weight and described the issues I was having.
I will certainly try to make it down to Southern Ohio for the next Rally!

Cheers

Great write-up, MGrider. And welcome to the Ghetto!

Pete (Street)

Thank you MGrider. Always interesting to learn from advanced GRiSO users

Thanks for the post, great info.

Did they provide much info on setup? Like once you tried it out, can you call up and they help you dial it in some?

For example, did you go over your preload numbers with them?

The rear shock sounds like a nice firm spring.

For the forks, you might try tightening up your preload ... like go from 42mm to, heck, I'd go to 35mm and try that. That sounds like a lot but 30-35mm preload is more normal than 42. And if you go to 35mm and don't like it, then you could try maybe 38mm, and not happy to back to 42.

usedtobefast wrote:

For the forks, you might try tightening up your preload ... like go from 42mm to, heck, I'd go to 35mm and try that.  That sounds like a lot but 30-35mm preload is more normal than 42.  And if you go to 35mm and don't like it, then you could try maybe 38mm, and not happy to back to 42.  

Changing preload will only alter the ride height with linear springs.  The spring rate remains unchanged.

Comfort/handling is so subjective.
I'm 5.7 and weight 165/170 so I could pass for an Italian, GRiSO was made for guys like us... the bike was never awful to me out of the box, not even close and it's still fine now. For regular street use that is...
Does it need adjustments on the stock suspension bits? Sure, but I don't feel the needs to replace the rear shock or the forks, and I track the bike once in a while.
I think that a set of Olhins forks would be a better spend than the rear shock but that's me. Heavy breaking require a better set up than the showa IMO but for regular street use, nahh...

usedtobefast wrote:

Thanks for the post, great info.

Did they provide much info on setup?  Like once you tried it out, can you call up and they help you dial it in some?

For example, did you go over your preload numbers with them?  

The rear shock sounds like a nice firm spring.

For the forks, you might try tightening up your preload ... like go from 42mm to, heck, I'd go to 35mm and try that.  That sounds like a lot but 30-35mm preload is more normal than 42.  And if you go to 35mm and don't like it, then you could try maybe 38mm, and not happy to back to 42.  

@usedtobefast, Penske provided me with a printed set up guide which covers the in's and outs. Additionally, I had some additional correspondence via email.
I thought about bumping my pre-load up just to try, but ran out of weather for now.

Here is a heresy.  I can't stop myself from commenting.  I have a 2009 GRiSO stock except for some cosmetic mods.  Had it for a year or so and couldn't be happier.  Replaced the muffler with the stock original as the engine is tuned for it and I like the sound.

I have had a 1980 Vespa 125 since the early 80's and have had many experiences with it and the people that liked them and wanted to "improve" them.  My scooter is engine modified only to the extent that it has a 166 or 177 cc aluminum cylinder and head.  This because some expert believed that the way to determine whether the mixture was right was to simply put the bike in neutral and open the throttle all the way and leave it that way.  He blew the engine.

My scoot starts on the first or second kick and has had the same plug uncleaned or changed for thousands of miles.  I don't think I ever saw a "modified" upgraded scooter that came anywhere close to that.  All the experts I spoke to turned out to be not well informed and seemingly unable to reason logically, and their modified scooters proved it.  I have also owned Alfa's Fiat's, Lancia's and a Citroen SM.

My conclusion after all these experience arises from thinking about the origins of not only the Vespa but the Guzzi and the other vehicles:  These Italians have decades of experience manufacturing these vehicles.  They employ engineers schooled in the arts do the job.  Do you really think they are idiots or uninformed?  More to the point, do you really think that Penske knows more about the bike and its handling than Guzzi?  If so, I couldn't disagree more.  Since Ford v. Ferrari is now a movie I did some research and found that Ford had 8 factory cars at Lemans in 1966 I believe, and literally millions of dollars in spares and personnel while Ferrari entered 2 factory cars.  Ford beat Ferrari not through superior tech, but the same way that the US "won" WWII, overwhelming, massive production and output. Some estimate that Ford spent $500 million to do so.  

You can do the same if you like but "improvement" won't come cheap or easy.  And there is no objective way to determine whether there has been any genuine improvement unless you want to spend even more time and money to perform objective tests, if that is even possible, or take it racing before and after.  Enjoy the pleasure of doing a modification right, but I'm a confirmed skeptic and its not for me.

If it hasn't been rollerised it is destroying its top end.

Your comments regarding suspension are naive and ignore one of the major reasons the suspension as delivered is pretty crap, namely cost.

The Showa forks are very good but they are poorly sprung and valved. The Sachs shock is really pretty garbage, to the point where my local suspension tuner reckons it's bordering on the unsafe! I wouldn't go that far but it's not good.

If you are happy with your bike stock? Fine! But believe me it could be a lot better.

Pete

What price satisfaction?
Nobody makes the bike I want, Tuono RSV4 1100 factory might be the exception.
Guzzi make an engine that I love the feel of, I made the rest. Problem solvered!

Quote :

These Italians have decades of experience manufacturing these vehicles.  They employ engineers schooled in the arts do the job.  Do you really think they are idiots or uninformed?  

Here, I fixed it for you:

"These Italians have decades of experience manufacturing these vehicles.  Piaggio employ bean counters schooled in the arts of el cheapo. They really think we are idiots and uninformed."




I spent a few bucks on Matris suspension front and rear. They're Italian, by the way. My kidney thanks me for it.

And then you have guys like me, I drive a 3/4 ton 4wd diesel truck and jeep rubicon.  My GRiSO 1100 just passed 60,000 miles with the stock (rebuilt front fork) suspension.

From riding horses and no-suspension/hardtail mountain bikes I've learned to use my legs on rougher roads.

When I want smooth I just take my V11 Lemans Rosso Corsa (Ohlins front and rear).

I just wish I could respring my GRiSO for my 240 lb geared-up weight.  (my research is there are no springs that fit)

Besides I'm saving my shekels for a Guzzi-Sidecar rig.  My hunting dogs really don't like being home when I'm gone on a tour.

Nice write up, hadn’t considered sending to Penske. Have a Matris on the back. Really need fork work to complete the bike. Might as well service starring head barings if they are still there lol. Will add bleeders to the stock MC as well.

Not-fishing Traxxion in Atlanta fixed up my stocker for 235lbs no problem. One day I will Get them to do the front end as well

Dilliw,

Did you have to send them the shock or just order the spring?

Also do you mind if I tell them to give me the same spring as George got?

not-fishing wrote:

Dilliw,

Did you have to send them the shock or just order the spring?

Also do you mind if I tell them to give me the same spring as George got?

My bike was wintering in Atlanta so Wayne just took the shock off and walked it in, but they know the bike well and will only need you to send them the shock. More than welcome to remind them of me however.

Here is the note from Dan Anderson the tech:



The stock spring is pretty soft, 490lbs, you would need in the neighborhood of a 750 for your weight. With that much of a spring rate change, it definitely needs a revalve. We can rebuild, revalve, and respring the shock for around $375 including custom setup and dyno tuning. That will make the ride and handling much better.

If I need a better shock I wouldn't know it; my GRiSO is setup far better than my skill.

Also, get one of their "shock condoms" and put that on there. I think it's $16 and protects the springs.