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General Category => General Discussion => Topic started by: Ncdan on August 11, 2020, 02:01:42 PM

Title: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 02:01:42 PM
Over the 55 years of ridding and dozens of different makes, models and types, I’ve learned one thing, When obtaining a different or new to you bike, one should ease into it by taking your time learning the bikes particulars as some definitely have quirks.
As many of you know I recently got an 02 Stone and trying to accumulate some miles, even in this heat, to check everything out.
Today was the, at highway speed test. The Stone came with the plexifairing 3 type windshield, made by Nation Cycle as I’ve been told, however the mounting system is different from the 3 other plexi3 I have owned. The actual Plexi 3 has mounting hardware which attaches in four points, 2 attached to the lower forks with brackets and 2 attaches to the handlebars/with brackets.
The stones mounting system is 4 brackets, 2 upper and 2 lower attached to the forks only. I’m not saying which is better or worse, just pointing out the hardware mounting system.
I have never detected or noticed and abnormal effects from the 3 plexi3 shields on any of my previous bikes, one being an 04 EV however not so with the Stone. On today’s ride while on the slab and just moving with the traffic, at slightly above 80mph the bike development a wobble. My experience and gut feeling told me not to push it any harder or I’d be in the middle of a “tank Slapper”, a mans got to know his bikes limitations and I found my Stones today.
Conversation welcome.

Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: nsmith on August 11, 2020, 02:26:47 PM
On my Bassa I found a squared off rear tire and too soft a setting on the rear shocks added up to a high speed tank slapper. however I would also be traveling up in the triple digit numbers on the speedo. Never had any issues at less than 100mph. That is using the Guzzi cop style windshield. New tire never acted up but in the flat lands of eastern South Dakota the tire is going to get squared off no mater what ya do.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Zoom Zoom on August 11, 2020, 02:29:33 PM
I have many, many miles behind that shield on the EV's I had, easily over 100K. I never experienced any trouble. Even topped out in Western Nebraska. I do realize this is a point of contention on the board,but after the junk steering damper went belly up, I put a much better aftermarket damper on both EV's. But like I said, I NEVER had any trouble in that regard. I never ran without a damper but I know many do.

John Henry
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 02:32:13 PM
On my Bassa I found a squared off rear tire and too soft a setting on the rear shocks added up to a high speed tank slapper. however I would also be traveling up in the triple digit numbers on the speedo. Never had any issues at less than 100mph. That is using the Guzzi cop style windshield. New tire never acted up but in the flat lands of eastern South Dakota the tire is going to get squared off no mater what ya do.
Interesting take on the shock issue. I just took out the preload tension on the rear shocking because the PO, 300lb
Feller, had really cranked them down! I only weigh 165-170 so I released the tension close to complete extension 🤔
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 02:34:51 PM
I have many, many miles behind that shield on the EV's I had, easily over 100K. I never experienced any trouble. Even topped out in Western Nebraska. I do realize this is a point of contention on the board,but after the junk steering damper went belly up, I put a much better aftermarket damper on both EV's. But like I said, I NEVER had any trouble in that regard. I never ran without a damper but I know many do.

John Henry
Was it the the same type shield mounted the same way, to the forks only?
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: mobiker on August 11, 2020, 02:35:13 PM
Take the windshield off. Go for a ride and repeat the conditions as close as possible.
No change? Its not the windshield.
All joy? It is the windshield.
Easy and reversible.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 02:39:54 PM
Take the windshield off. Go for a ride and repeat the conditions as close as possible.
No change? Its not the windshield.
All joy? It is the windshield.
Easy and reversible.
That’s probably good advise Mo but I really don’t want to remove that shield as I had to do some redoing from the factory attaching symptom to get it attached.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Zoom Zoom on August 11, 2020, 03:13:03 PM
Was it the the same type shield mounted the same way, to the forks only?

Yes sir! I actually sold an original Swanee off my second EV and found another one of these. Guzzi accessory NM002, or NM0002 "California Sport Touring Shield" because I liked it so much on the bike I lost in the flood.

Now that they're nearly impossible to find, I would still try to seek one out if I got another late Tonti Cali.

John Henry
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 03:34:17 PM
Ok guys I’ve got to start somewhere so I think the steering damper is as good a place as any.
Could some of you guys school me as to how to adjust?
I adjusted the one on my EV and Calvin from one extreme to the other and road the same road over and over as I adjusted and never did feel any changes or difference, go figure.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Rough Edge racing on August 11, 2020, 03:57:00 PM
 Before doing anything mechanical, get up to speed again and lean forward as much as possible...This can often stop or lessen a wobble...Of course you can't ride like this very long but it may give a clue...It can something simple like a tire air pressue adjustment....or steering bearings, or what others have said...
   
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 04:35:27 PM
Before doing anything mechanical, get up to speed again and lean forward as much as possible...This can often stop or lessen a wobble...Of course you can't ride like this very long but it may give a clue...It can something simple like a tire air pressue adjustment....or steering bearings, or what others have said...
 
Bike just turned 10k so the bearings are fine and I have checked the tension and there’s no play. I’m thinking it’s Possibly the shields effect. I’ve eliminated any tire issue, New tire on the front, I did drop from a 110 to a 100 series.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: TN Mark on August 11, 2020, 07:24:33 PM
Yes sir! I actually sold an original Swanee off my second EV and found another one of these. Guzzi accessory NM002, or NM0002 "California Sport Touring Shield" because I liked it so much on the bike I lost in the flood.

Now that they're nearly impossible to find, I would still try to seek one out if I got another late Tonti Cali.

John Henry

Yes sir! I had two of them as one was lost when I wrecked my 99 Bassa. I immediately bought a second NM002 California Touring Shield for the second Bassa. I also thought it worked much better than the Swanee fairing I also had at the time. IMHO, the NM002 out performed the Swanee and looked great doing so. Finding that shield now could be a task, finding the mounting hardware could be even harder. The Classic windshield that was first offered for the Bassa looked great but performed horribly.

NCDan, If the angle of your current windshield can be adjusted, that’s a path that could be worth traveling. But first, as has been suggested, remove the shield entirely to verify the situation is with the bike or the shield.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: lucian on August 11, 2020, 07:37:01 PM
Did you have your banjo strapped on your back again? Mabe the box sticking out one side and the neck out the other created an imbalance in the airstream. :boozing:
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 07:42:35 PM
Did you have your banjo strapped on your back again? Mabe the box sticking out one side and the neck out the other created an imbalance in the airstream. :boozing:
Lol you ole Salt, but you may have a point👍
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Huzo on August 11, 2020, 07:43:55 PM
Did you have your banjo strapped on your back again? Mabe the box sticking out one side and the neck out the other created an imbalance in the airstream. :boozing:
A banjo player with inherent instability...?
Never let it be said.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 08:00:26 PM
A banjo player with inherent instability...?
Never let it be said.
Huzo, with buddy pals like you and Lucian I hope I don’t make any enemies here🤣🤣🤣
Now how about some helpful suggestions on how to fix my wobble so as I can speed and break the law :copcar: :copcar:
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: lucian on August 11, 2020, 08:21:03 PM
If a 300lb. rider had been riding it with the suspension cranked up I would be giving the suspension front and rear a thorough once over. check your sags and front forks for proper damping ect.  Tire pressure and balance also.  Check out the basic setup stuff before overthinking it.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: LowRyter on August 11, 2020, 08:54:10 PM
I have no comment regarding your experience riding the bike. 

I do agree with your position that the Plexi 3 should attach to the bars and and forks.  I'd like to get another P3 for my EV.  They are great.  But you are correct regarding  the installation.  This one is installed wrongly IMO.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Zoom Zoom on August 11, 2020, 09:00:54 PM
Can't be wrong. It only fits one way.

ZZ
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 09:06:27 PM
I have no comment regarding your experience riding the bike. 

I do agree with your position that the Plexi 3 should attach to the bars and and forks.  I'd like to get another P3 for my EV.  They are great.  But you are correct regarding  the installation.  This one is installed wrongly IMO.
Yea LR the P3 is a great shield and I had one on my EV as well. Great protection from the wind and elements and I can’t remember any adverse issues at speed. I’m not sure yet that’s it’s a shield issue. Thanks for the response 👍
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 09:14:29 PM
I may have an answer to the issue offered by one of the guys here.
The guy that had the bike was a big guy 300lb and had really cranked the compression down on the rear shocks, probably 25-30 percent of the springs load. In turn, I let it off most all the way back to the top. Possibly making it too soft causing the bike to become unstable as more weight is shifted to the rear as speed increases. ???
I’ll check that tomorrow and report back.
Thanks everyone for the input, I’ll get this babe right sooner or later 👍
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Guzzistajohn on August 11, 2020, 09:15:41 PM
I find it interesting how many spell riding with a double d  :wink:
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 09:26:23 PM
I find it interesting how many spell riding with a double d  :wink:
Not that it really matters but that’s the way it spells it when dictating the message at times. I’m fairly sure it will not increase or decrease the wobble my bike is experiencing😉
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: pehayes on August 11, 2020, 09:47:45 PM
The actual Plexi 3 has mounting hardware which attaches in four points, 2 attached to the lower forks with brackets and 2 attaches to the handlebars/with brackets.

Um, you might want to re-think that sentence.  The lower forks bounce up and down with the wheel while the handlebars do not.  Such a mounting would certainly create some strange dynamic performance.

I'm sure you meant that the lower mounts were on the lower triple clamp which is actually clamping the upper forks.

Having said that, in 1979 I went to the National Rally in Sylvan Grove, KS.  In attendance were a couple of stout Iowa farm boys riding two-up on an Ambassador.  They had fabricated home-made, plywood panniers.  One end was attached to the upper frame and the other end was attached to the swing arm.  The boxes pivoted with every bump.

Patrick Hayes
Fremont CA
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Huzo on August 11, 2020, 11:04:17 PM
I find it interesting how many spell riding with a double d  :wink:
You will now have to be extremely careful when posting....
I can hardly wait... :clock:
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 11, 2020, 11:18:39 PM

(https://i.ibb.co/JtHXxMn/1-E48-D475-213-F-4462-AD3-C-94-C4-C68500-EE.png) (https://ibb.co/JtHXxMn)

(https://i.ibb.co/bHCdLpN/CE5-E966-B-BAE7-4-CE2-A959-471-C7-A417-AD3.png) (https://ibb.co/bHCdLpN)
Um, you might want to re-think that sentence.  The lower forks bounce up and down with the wheel while the handlebars do not.  Such a mounting would certainly create some strange dynamic performance.

I'm sure you meant that the lower mounts were on the lower triple clamp which is actually clamping the upper forks.

Having said that, in 1979 I went to the National Rally in Sylvan Grove, KS.  In attendance were a couple of stout Iowa farm boys riding two-up on an Ambassador.  They had fabricated home-made, plywood panniers.  One end was attached to the upper frame and the other end was attached to the swing arm.  The boxes pivoted with every bump.

Patrick Hayes
Fremont CA
I don’t know if you’ve ever Actually owned or saw these shields or mounting system but yes the bracket does mount to the upper portion of the fork itself, above the fork action.  The size of the clamp that holds the lower mount depends on the size of the fork tube. Thanks for your input however.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Knuckle Dragger on August 11, 2020, 11:20:07 PM
Nothing wrong with Double Ds.  I find their owners quite..... versatile.

Incidentally, older BMW Boxers are quite notorious for their tendency to weave at speed.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Testarossa on August 12, 2020, 12:43:45 AM
Start at the back and work forward. Look for rear-wheel balance, looseness or asymmetry in the swing-arm pivots, loose shock pivots. Retorque the steering head bearings. Check that the fork tubes are even in the triple clamps, and retorque the clamps. Also check that the fork tubes are really parallel in both axes -- I've seen straight tubes in bent triple clamps. Any damage inside the forks, to the dampers or springs? Front wheel balance? The windscreen might be the problem but not necessarily.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Huzo on August 12, 2020, 06:10:32 AM
Nothing wrong with Double Ds.  I find their owners quite..... versatile.

Incidentally, older BMW Boxers are quite notorious for their tendency to weave at speed.
Like the old Wild West gunslinger entertaining the saloon lady in Tombstone. He was clutching a pair of 38’s...
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: geoff in almonte on August 12, 2020, 06:42:26 AM
Like the old Wild West gunslinger entertaining the saloon lady in Tombstone. He was clutching a pair of 38’s...

He also carried a gun.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: geoff in almonte on August 12, 2020, 06:50:34 AM
Check the clearance between the headlight and the windscreen - you should allow a gap of at least an inch to allow air under the windscreen.

At speed, the screen creates a vacuum which in turn causes uneven airflow behind the screen which could result in a wobble.  The effect is similar to riding in the turbulence behind a transport.

G
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Bulldog9 on August 12, 2020, 07:01:56 AM
Simplest is to remove the WS and go for a test ride. 

Large Fork mounted screens can induce high speed wobbles and expose weaknesses in the chassis. Steering head bearings, imbalance in fork oil, misaligned fort tubes/triple trees/axle, steering stabilizer, sometimes rear suspension as well with things like swing arm bearings.

Tires can play a big role as well. I never replace only front or back tires, always a fresh set. Changing just the front and changing profile may play a part as well.

Don't discount a poorly aligned windscreen either. Is the screen adjustable? Can you move it up or down in height? Have you checked it for being square?

I had a series of WS on my XS11 from a frame mounted Windjammer to a fork mounted Rifle with different height clear shields. The Stock and tall shields were steady as a rock, but when I cut one down to 1/2 stock height, it became a wobble monster with no cure. Had a similar experience on my C10 Concours.

Because I am cheap, I adapted the large Norge Windscreen to the Stornello, using adapter plates to connect to the DART screen mount. I lucked out, after some adjustment of rake and angle, I ended up with no wobble to 90 MPH, even on the super light V7 chassis. The screen is large, but properly aligned you can tune out wobble.

As it is a new bike, I'd go over it all top to bottom, but $10 says taking the windscreen off for a series of high speed runs will eliminate the shake.


Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: s1120 on August 12, 2020, 07:32:36 AM
Bike just turned 10k so the bearings are fine and I have checked the tension and there’s no play. I’m thinking it’s Possibly the shields effect. I’ve eliminated any tire issue, New tire on the front, I did drop from a 110 to a 100 series.

I would have guessed the head bearings also. My 02 stone did the same thing, but on slower back road corners. It was worse with the sheld on... bit still there with it off. Once I got the front in the air I noticed the head bearings were REAL sloppy!!!!  WAY out of wack, and my bike was also under 10k miles.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 12, 2020, 08:01:02 AM
Thanks for all the responses, suggestions and recommendations and I have taken every one of them in consideration and will address until the issues is solved. Also let me reiterate it’s not a great big issue because I seldom reach the speed of 80mph mainly because I don’t to have to explain to an officer why an old retiree is acting like a fool😂 Just funning. However the bike is very stable and solid displaying no issues at all until yesterday when I hit that 80mph zone. It then corrected itself when I backed off a bit which could have been a serious wobble if I had proceeded to increase my speed.
Today I will put some of the compression back on the rear shocks, as a couple of the knowledgeable guys suggested, which I had removed a couple days earlier. I had released all of the compression the heavy PO had torqued down and let’s see what that does.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: oldbike54 on August 12, 2020, 08:41:33 AM
 Have watched one '97 California do the "dance" at speed , and have had a 2002  model brought to me after the owner experienced a serious head shake . In both cases a fork seal on one side had been leaking , leaving one side almost empty of fluid . The '97 has that crazy barn door handlebar mounted fairing and 40 liter H&B bags , the '02 just had a very small turbulence generator that stuck up about 3 inches above the headlight and small stylized bags .

 Patrons at the truck stop in Missouri seemed amused watching as we disassembled the '97 California in the shade of the one lone tree on the property .

 Dusty
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 12, 2020, 09:00:28 AM
Have watched one '97 California do the "dance" at speed , and have had a 2002  model brought to me after the owner experienced a serious head shake . In both cases a fork seal on one side had been leaking , leaving one side almost empty of fluid . The '97 has that crazy barn door handlebar mounted fairing and 40 liter H&B bags , the '02 just had a very small turbulence generator that stuck up about 3 inches above the headlight and small stylized bags .

 Patrons at the truck stop in Missouri seemed amused watching as we disassembled the '97 California in the shade of the one lone tree on the property .

 Dusty
Thanks for that information Dusty. I think I can eliminate any fork or front end issues at this time. There are no signs of any leaks in the forks, I know any seal can start leaking but its obviously not leaking now or ever in its 10k miles. When the new tire was replaced Monday my mechanic checked the Head bearings and tension and all was fine.
Today I’m going to put some preload back on the rear shield which I had removed ALL of what the PO had added and see what that does 👍
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: wirespokes on August 12, 2020, 10:08:15 AM
Why not set the suspension properly with sag at 1/4 - 1/3 total travel?

Stock shocks don't tend to be quality items. Maybe one (or both) aren't doing so well.

Tires can have internal issues. I had a front tire that was maybe 50% worn, looked fine, but replacing it fixed a bad low speed wobble.

A worn rear tire can cause wobbles.

Swing arm bearings and adjustment also.

Considering others have had no issues with the fork mounted wind screens, I'm guessing it's not the issue. And even though the wobble is above your normal speed, it needs to get resolved. You'll be passing a semi at high speed one day and the change in wind speed, pressure and direction will bite you big time!

It's even possible the PO sold the bike because of this issue.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 12, 2020, 10:24:46 AM
Why not set the suspension properly with sag at 1/4 - 1/3 total travel?

Stock shocks don't tend to be quality items. Maybe one (or both) aren't doing so well.

Tires can have internal issues. I had a front tire that was maybe 50% worn, looked fine, but replacing it fixed a bad low speed wobble.

A worn rear tire can cause wobbles.

Swing arm bearings and adjustment also.

Considering others have had no issues with the fork mounted wind screens, I'm guessing it's not the issue. And even though the wobble is above your normal speed, it needs to get resolved. You'll be passing a semi at high speed one day and the change in wind speed, pressure and direction will bite you big time!

It's even possible the PO sold the bike because of this issue.
Thanks WS for that info. In the “Sag Spec” is those numbers you stated measured when my weight only is on the Bike??
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 12, 2020, 11:18:57 AM
He was saying that the fork tube in question is not the FORK LOWER - he was basically saying the way you wrote it made us picture someone trying to attach the lower clamp/mounting bracket not the fork tube, but the larger diameter slider below it which some call a "fork lower". That is all. I'm staying out of the rest cause it seems to be covered.
No problem and thanks. I guess I figured that’s it’s obvious the latter could not happen. All is good and I appreciate everyone’s input. Now the next post will answer all the questions. Thanks Kev
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: MMRanch on August 12, 2020, 11:19:58 AM
 :shocked:

Ncdan

Where do you live where the speed limit is Slightly above 80 ?

 :huh:


Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Tkelly on August 12, 2020, 11:42:53 AM
My 2cents,you are talking about a lot of work.What if you do all that stuff and still have the problem?You will have to remove the shield then. my eldo did this a couple times before I pulled the old widow.It was solid up to 100 then.Good luck but don’t do the speed test on the freeway.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 12, 2020, 11:50:41 AM
Problem solved!!!!
First let me say thanks to everyone that took of their time to respond and a couple of you guys hit the proverbial “head on the nail”.
I probably need to start by asking all to look over my testing procedure as it’s probably considered reckless and irresponsible but some times drastic actions snd need to fix particularly drastic events.
When I took possession of the bike the PO had cranked the compression aspect of the rear shocks probably to 30% of full compress status. It road very ruff, so at my weight of 170 in full gear, I figured an uncompressed shock should be ok. After talking To one of the guys here Last night Who suggested putting at least half that preload back on.
So this morning I did just that. After making a pre run to check for energize LEO running radar, I got off the ramp and headed the other way, 4 lane but not interstate, Traffic was fast, around 80mph. I fell behind the line and backed off about a half mile, then let her go. From 80 to 100 MPH she was as steady and firm as a real mans handshake. Absolutely Stone solid!
I think one thing we can take from this is which shields and which positions they are mounted probably does not effect these issues of stability at higher speeds. I think the bikes suspension should be the place to start in fixing the issue.
Thanks again for the help guys and please overlook any weird or strange thing I may have said as sometime I slip.  👍
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: wirespokes on August 12, 2020, 11:58:54 AM
Here's the data on sag. The suspension has to be able to absorb bumps, but it also needs to track depressions or pot holes as well. So those are two opposite vectors.

Because of that the suspension has to be free to move both up and down.

It's been found that the best place to set the suspension is 1/4 to !/3 from the top. Bumps evidently need more travel than holes.

There are a few ways to determine what the 1/4 distance is. With the wheel off the ground, measure from the axle to the frame. That will get you full extension.

Look up the specs on the shock, or for the bike, for full suspension travel. Say it's 3".

Now take the bike off the stand, and sit on it. Have a friend measure the distance from the axle to the frame and it should be 3/4" to 1" less.

You can also put a zip tie on the shock piston rod at full extension, sit on the bike, then put it back on the stand. You'll be able to see how far the suspension moved.

Glad it did better this time and got rid of the shake. For now anyway. By increasing rear shock preload, ride height was increased. That in turn changed the steering head angle and the angle of attack of the wind screen. Hopefully the sag is correct. If it's stiff, then more work is needed and this is another data point to consider.
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 12, 2020, 12:12:51 PM
Here's the data on sag. The suspension has to be able to absorb bumps, but it also needs to track depressions or pot holes as well. So those are two opposite vectors.

Because of that the suspension has to be free to move both up and down.

It's been found that the best place to set the suspension is 1/4 to !/3 from the top. Bumps evidently need more travel than holes.

There are a few ways to determine what the 1/4 distance is. With the wheel off the ground, measure from the axle to the frame. That will get you full extension.

Look up the specs on the shock, or for the bike, for full suspension travel. Say it's 3".

Now take the bike off the stand, and sit on it. Have a friend measure the distance from the axle to the frame and it should be 3/4" to 1" less.

You can also put a zip tie on the shock piston rod at full extension, sit on the bike, then put it back on the stand. You'll be able to see how far the suspension moved.

Glad it did better this time and got rid of the shake. For now anyway. By increasing rear shock preload, ride height was increased. That in turn changed the steering head angle and the angle of attack of the wind screen. Hopefully the sag is correct. If it's stiff, then more work is needed and this is another data point to consider.
Thank you so much for taking the time to give me those specs and guide lines and I’ll definitely use it as a guide and reference. Thanks!!
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: BrotherJim on August 12, 2020, 12:37:04 PM
Last time I rode my '02 Stone with my Givi's attached and loaded and my Dart Marlin windscreen, I experienced a bit of wobble at, let's say 90mph.  Slowed down to closer to 80mph and the wobble went away.  Now, I put new shocks on it a while back before I got the notion that I'd be putting bags on it, and I set the sag at 220lb at that time.  I've got fresh-ish Metzeler 880's with about 3,000 miles on them.  I think that what I was experiencing was being overloaded for my chosen preload settings.  If any of the other suggestions don't yield favorable results, maybe get a buddy to help you set the suspension sag to your expected weight range.  I honestly don't think that the steering damper does much, except look kind of cool. 
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: Ncdan on August 12, 2020, 01:00:41 PM
:shocked:

Ncdan

Where do you live where the speed limit is Slightly above 80 ?

 :huh:
I didn’t say  the speed limit was 8o, MM, I said the traffic was collectively running around 80👍
Title: Re: Windshields and tank slappers Definitely Guzzi content
Post by: BrotherJim on August 12, 2020, 04:32:28 PM
Ha!  Late to the party, I guess.  Glad you've got that sorted.  These really are great machines.