Ducati.ms - The Ultimate Ducati Forum banner

61 - 71 of 71 Posts

·
Registered
Joined
·
5,806 Posts
The stock GSXR spring rate is fairly low, somewhere in the 70-80 # range , iirc. The springs are also much shorter than Ducati springs. There is probably a way to use them, but the conversion is easiest if you buy springs meant for a Ducati in the rate you need.
 

·
Premium Member
Joined
·
3,555 Posts
I also want to add that before you throw away useable fork parts be sure to decide on what works for you vs what the "best" will be.

Is there overlap of damping in the old showa design? Absolutely!
Does it matter most of the time ? Absolutely NOT!

As Mentioned if you completely run an adjuster to one end of the range there will be an effect on another circuit. Well when you are setting up suspension this is usually a problem once when you first learn this and after that you know what will happen so you plan for the other change. All those Ohlins shocks that are desired for the supersport do exactly the same thing does it mean they are defective? No , it means you need to understand what a clicker does when you use it.

If there is a "fix" then yes it may be beneficial to someone who is needing to adjust often say a racer who visits different tracks and is needing to make changes to suit. Most customers (including many racers) will never touch an adjuster once set. Some will never stop adjusting simply due to a bit of interest or OCD where they can not help themselves.

I can not think of a time where I have ever set up a fork regardless to brand or type where the adjusters were left in a extreme position (max or min), usually they should be in the middle 50% when set up. If I find them at an extreme that is telling me something is not right and it is fixed, often by changing valve,valve stack or oil weight. Does this mean a 41mm showa will be as good as a ohlins when done? Depends on how BAD the Ohlins is to say. I have seen plenty of good forks poorly setup over the years that had all the right parts but were not as good as a poor design set up well.

Now I will not say there is anything wrong with changing the internals of the old showas, do a good job and you should get good results. Modding these bikes can easily be as fun as riding them so do not take it that I am trying to stop anyone from that. I just want new owners of these older designs to know that as always there are many options and levels and someone who is re-inventing the wheel may make a better wheel...but it may not be better in practice for the person thinking they are in the same circumstance.

I have had plenty of experience with these "Defective" showas working plenty well for owners for over 20 years where there was not a desire to change anything after the fact. This leads me to believe that it is possible to be happy with what can be done with the 41's . There are a few years of 43's that are truly different and i would say defective but thats another story. Damping of the 41's can be an issue but is it a bigger issue that pitting chrome or flexing of the fork?

Given the cheap cost of used gsxr fork internals I would say that is a good route as long as they can be mostly drop in, Replacement valves will be almost as much so if you can get a better design for close to the same money why not. Where it will all go sideways is if you need to spend $$$ making them fit you get closer to the cost of changing to a 43 that while of similar design internally has fewer issues with pitting or flexing. Once you cross a price point the anser changes for me but everyone has to determine their own red line to cross.
 

·
Registered
Joined
·
1,274 Posts
I also want to add that before you throw away useable fork parts be sure to decide on what works for you vs what the "best" will be.

Is there overlap of damping in the old showa design? Absolutely!
Does it matter most of the time ? Absolutely NOT!

As Mentioned if you completely run an adjuster to one end of the range there will be an effect on another circuit. Well when you are setting up suspension this is usually a problem once when you first learn this and after that you know what will happen so you plan for the other change. All those Ohlins shocks that are desired for the supersport do exactly the same thing does it mean they are defective? No , it means you need to understand what a clicker does when you use it.

If there is a "fix" then yes it may be beneficial to someone who is needing to adjust often say a racer who visits different tracks and is needing to make changes to suit. Most customers (including many racers) will never touch an adjuster once set. Some will never stop adjusting simply due to a bit of interest or OCD where they can not help themselves.

I can not think of a time where I have ever set up a fork regardless to brand or type where the adjusters were left in a extreme position (max or min), usually they should be in the middle 50% when set up. If I find them at an extreme that is telling me something is not right and it is fixed, often by changing valve,valve stack or oil weight. Does this mean a 41mm showa will be as good as a ohlins when done? Depends on how BAD the Ohlins is to say. I have seen plenty of good forks poorly setup over the years that had all the right parts but were not as good as a poor design set up well.

Now I will not say there is anything wrong with changing the internals of the old showas, do a good job and you should get good results. Modding these bikes can easily be as fun as riding them so do not take it that I am trying to stop anyone from that. I just want new owners of these older designs to know that as always there are many options and levels and someone who is re-inventing the wheel may make a better wheel...but it may not be better in practice for the person thinking they are in the same circumstance.

I have had plenty of experience with these "Defective" showas working plenty well for owners for over 20 years where there was not a desire to change anything after the fact. This leads me to believe that it is possible to be happy with what can be done with the 41's . There are a few years of 43's that are truly different and i would say defective but thats another story. Damping of the 41's can be an issue but is it a bigger issue that pitting chrome or flexing of the fork?

Given the cheap cost of used gsxr fork internals I would say that is a good route as long as they can be mostly drop in, Replacement valves will be almost as much so if you can get a better design for close to the same money why not. Where it will all go sideways is if you need to spend $$$ making them fit you get closer to the cost of changing to a 43 that while of similar design internally has fewer issues with pitting or flexing. Once you cross a price point the anser changes for me but everyone has to determine their own red line to cross.
Yes, good pragmatic advice for those without unlimited resources to spend on stuff they may not need. In fact, both the non-adjustable Showas and Marzocci forks can be entirely adequate. I've seen quite a few bikes with these forks where the oil has never been changed - yes, in 25 years. It absolutely STINKS when you pour it out. New oil, playing with the oil height when preload adjustment isn't an option, different oil weights, these can give (many of) the same desired effects as a set of $2000 Ohlins forks, you just can't adjust them on the fly. Fact is, most people never adjust them.

I did the GSXR upgrade because it was cheap and I could (afford to) and I wanted better feel because I was finding it really hard to adjust the Showas to my liking. YMMV. I found it to be a worthwhile upgrade. As I said in one of my previous posts in this thread, the biggest bang for the buck for me was RaceTech linear springs for my weight, the rest was more incremental improvements but the springs (and probably new oil) was huge.
 

·
Registered
Joined
·
5,806 Posts
As far as preload adjustable caps go, the GSXR caps fit the Ducati forks so folks who’ve done the conversion will have one or the other lying around. They could be used to add preload adjustments to the basic type if someone wants to part with them.
 

·
Registered
Joined
·
1,524 Posts
As far as preload adjustable caps go, the GSXR caps fit the Ducati forks so folks who’ve done the conversion will have one or the other lying around. They could be used to add preload adjustments to the basic type if someone wants to part with them.
Could be. My ignorance of all things Ducati Forks doesn't permit me to speak either positively or negatively about it.

I'm shelving the fork cap notion for the time being. I'll, instead, focus on improving the non-adjustable Marzo sticks within the four or so parameters those forks make available (oil changes, air space, spring rate/type, and preload). There are other things that can be changed that will also improve handling that don't cost a shopping bag full of munney (unsprung weight, rotational weight, tire profile and tire weight, frame stiffening options, and so on). I'll also focus on seeing what can be done with the rear suspension without actually having to spend money on an Ohlins. The point being to create a motorcycle with balanced handling and balanced weight distribution.

That doesn't mean I'll discontinue fielding questions and ideas about various things though!!

:wink2:
 

·
Registered
Joined
·
1,274 Posts
Could be. My ignorance of all things Ducati Forks doesn't permit me to speak either positively or negatively about it.

I'm shelving the fork cap notion for the time being. I'll, instead, focus on improving the non-adjustable Marzo sticks within the four or so parameters those forks make available (oil changes, air space, spring rate/type, and preload). There are other things that can be changed that will also improve handling that don't cost a shopping bag full of munney (unsprung weight, rotational weight, tire profile and tire weight, frame stiffening options, and so on). I'll also focus on seeing what can be done with the rear suspension without actually having to spend money on an Ohlins. The point being to create a motorcycle with balanced handling and balanced weight distribution.

That doesn't mean I'll discontinue fielding questions and ideas about various things though!!

:wink2:
Very rational plan. Note that for the rear suspension, the shock from 99+ model years is about 10mm longer which, if you're looking to improve nimbleness/turn-in, will help out significantly. A lot of folks, myself included, drop the front down a few mm's for this reason (lower forks in triple clamp) and I never had any clearance issues but others opt to go with the longer shock... YMMV, sometimes you see them for cheap. Also, the stock OEM spring on the rear is designed to accommodate 2-up riding. A softer spring appropriate for your weight will make quite a difference in bump handling.

If you haven't replaced tires, new tires generally give you the impression of riding a suddenly modernized motorcycle that handles an awful lot better than the old dog with the superslab flat spot on the tires.
 

·
Registered
Joined
·
1,524 Posts
Very rational plan. Note that for the rear suspension, the shock from 99+ model years is about 10mm longer which, if you're looking to improve nimbleness/turn-in, will help out significantly. A lot of folks, myself included, drop the front down a few mm's for this reason (lower forks in triple clamp) and I never had any clearance issues but others opt to go with the longer shock... YMMV, sometimes you see them for cheap. Also, the stock OEM spring on the rear is designed to accommodate 2-up riding. A softer spring appropriate for your weight will make quite a difference in bump handling.

If you haven't replaced tires, new tires generally give you the impression of riding a suddenly modernized motorcycle that handles an awful lot better than the old dog with the superslab flat spot on the tires.
Great advice. :smile2:

My tires are 18 month old Pirelli Angel GTs with about 1,500 miles on them. The previous owner was just a "ride to work" sort so the tires aren't all flat down the middle or torn up otherwise. I'm still doing research on tires (weight, profile, and aspect ratio, performance, etc..). The rear is a 170, when it wears out I'm thinking about going down to a 160 (my CR has a 4.5 inch rim). Less weight, easier tip in.

I've already bought one of those BBB Fab frame braces (brand new), it's sitting right here on the desk ... I need to paint it before I install it. Steve's ever-so-lightly rusted fingerprints are on it ... he bead blasted the brace after building it and then touched it with his bare hands ... makes fingerprints. So I'll sand it a little, then hit it with some paint. Also found a NOS set of CNC machined chain adjusters to replace those stamped steel crappy ones. Those machined adjusters also do their part in helping to add a small bit of rigidity to the stock steel swingarm. The only other frame stiffening measure will be to install a Nichols Frame Bolt kit.

I'm leaving the stock steel swingin' arm on the bike. There's not enough return on investment to put an aluminum swinger on the bike, at least that's how I see it. Better money is spent on lighter, more narrow rear tire (again, my perspective).

Sprockets and chain are relatively new ... 200 miles/7 months old. 41x15 ... aluminum Renthal in the rear. I'm also going to install the low-slung rear caliper with the fully floating caliper hanger and rod. I already have the caliper, hanger, rod, engine/rod bracket, and spacers on hand. I just prefer the look, and the idea that the suspension doesn't bind up over bumps when the rear brake is applied. Those were all the rage when I raced MX in the 70s/80s. They were also on many street bikes and road race bikes of that time. I dig the nod to that era and the nostalgic look, as well as the fully floating caliper mount's function, especially over stutter bumps when approaching stop lights/signs. It's so hot out here that the stutter bumps can become pretty bad ... the asphalt gets soft enough to leave a very clear tire mark or foot print .. like mud.

Doing what I see as making the suspension free-working, reducing unsprung weight and rotational weight, and even taking off a few pounds of sprung weight by just replacing certain items when they age-out with lighter modern units (L-Ion batt for one ... I already picked up an Anti Gravity unit ... 10.5 pounds lighter than the lead/acid lump that was in the bike). New heavier gauge batt cables already bought as well. Stainless braided hydraulic lines are up next, along with a brand new MOSFET voltage reg.

No goofiness like drilling or cutting out the airbox lid, using wonderfully refurbed stock carbs (done by Ducatiman), and GPR Deeptone INOX slip ons which replace the fake Termignonis that are cracked and came with the bike. GPR slip ons are already on hand.

Bla bla bla ...

:wink2:
 

·
Registered
Joined
·
407 Posts
I may be wrong but ask DucVet I think he races with the non-adjustable forks on his 900ss--if so he has those set up where they work well--maybe he would tell you what he did to his and that may help you make your work properly. just an idea
 

·
Registered
Joined
·
1,524 Posts
I may be wrong but ask DucVet I think he races with the non-adjustable forks on his 900ss--if so he has those set up where they work well--maybe he would tell you what he did to his and that may help you make your work properly. just an idea
Thank you for the suggestion!

Truth told, I've been corresponding with him out of public forum on this issue as well as a number of others for several weeks now. He's a deeply experienced person and very willing to help.

:smile2:

Re; putting the non-adjustables to work ... those types of front suspenders have been used for decades, at least six or seven. We used them in the 1970s on MX bikes, and in the 80s they were used by many people racing in streetbike classes. Most would-be Rudy Racers have zip clue what to do with adjustable front ends anyhow, they'd be far better off with less adjustability since it wouldn't tempt endless fiddling which many times only results in creating a completely fuddup motorcycle.

Many times it turns out that less is better.

Thanks again for the suggestion, I'm sure other folks reading this thread over the years to come will find what you've said to be very encouraging and helpful!

:wink2:
 

·
Registered
Joined
·
1,423 Posts
i refitted the 40mm marzocchi to the m600 i'm getting rid of recently, and replaced the oil with maxima 7 weight, which is 26.7 cst at 40 degrees c. the springs are 0.85. it's a bit springy just bouncing, and i was considering going the 10 weight. historically i have used 10 weight in them with replacement springs. 7 would be more appropriate with the std springs. 10 weight is 37.4 cst.

my suspension man says the rebound valving in them is quite good.

one thing to be wary of with them if replacing springs is that you want the spring to be no longer than the originals, which are around 280mm. i replaced some in a customer's bike a while ago with some that were 340mm or so i think, and with them the spring came up above the top of the inner tube, and when assembled the inner tube could hit the preload tube, as there's no centre location. which means the fork just stops. putting the spring on top made it scrape rather horridly noise wise.

i'd committed to the job, so ended up machining a plastic piece that was a tight fit around the rod and located both spring and preload tube and had holes drilled in it to allow the air to move. nice job in the end, but a real pita, and i've just realised, when looking for the info, i didn't book the springs out to the job, as well as not getting paid to fix the mess id generated. bugger.
 

·
Registered
Joined
·
4,532 Posts
61 - 71 of 71 Posts
Top