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Old 11-01-2013, 02:16 PM   #16
motojunky
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Quote:
Originally Posted by StuInFH View Post
If you had read above, you'd know the problem is with me. lol

Yeah, the pull is easy enough for trials, but I'm setting the bike up for an all day trail bike for Rubicon and Fordyce, if that means anything to you. If I can get the lever pull down to my girlie-bike 690R, I'll be happy.

Just man up!




Sorry, couldn't resist. I'm following this with interest - mainly 'cause it's nice to read about a Scorpa once in a while. I wonder if you contacted an aftermarket clutch company (is Barnett still around?) with the spring measurements they'd be able to do the cross-referencing that the dealer can't?
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Old 11-01-2013, 02:56 PM   #17
StuInFH OP
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Quote:
Originally Posted by motojunky View Post
Just man up!




Sorry, couldn't resist. I'm following this with interest - mainly 'cause it's nice to read about a Scorpa once in a while. I wonder if you contacted an aftermarket clutch company (is Barnett still around?) with the spring measurements they'd be able to do the cross-referencing that the dealer can't?
Yeah, I only expected to hear from you. It seems no matter how much background I gave first or how direct my questions, I got the same stuff, or nothing. Like I said above, Barnett no help. I asked for dimensions of 250 and 80 YZ springs (125 and 250 are the same), hoping I can match some up, like this "Looking for springs that I can use that are ~30% lighter than OEM. Do you have the dimensions for 250 and 80 YZ springs, including wire diameter and/or spring wt? thank you" and "Mike" said, "Stuart, Afraid all of the springs we make are stronger than stock. That's what we normally make. Sometimes they are close to stock, but never lighter. Sorry!."

No sheet. Now about those dimensions I asked for?....sheesh. I clarified my request, even giving them their PNs, but then got silence (maybe they'll get back to me Monday with their secret numbers).

Best response was from some bozo on thehellteam in OZ who, after I explained I had 5 springs, told me removing springs will make it slip and if I want a lighter clutch to get a GG. and we wonder why the sport just fizzles...

Chris at Splatt Shop gave me ALL of the dimensions of their soft springs, real nice guy. And Mike at Tryals Shop was very helpful too.

If you wanna talk Scorpa, I can post up how I love the bike for the Rubicon over the Sherco (that suffered broken frame downtubes from a mild huck off a boulder). And then I'll wait for folks to tell me to get a modern bike with a REAL trials motor. :-)
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Old 11-03-2013, 10:56 PM   #18
Luke
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A couple of thoughts:

How about taking some stock springs and cutting coils off them? It'll make the spring rate higher but the force will be lower because the preload will be less.

Or, how about industrial spring suppliers?

Google brought up an ad for these guys: http://www.springsfast.com/
They have lots of available springs.

I guessed 0.6" od x 1.25" long and got these:

Part NumberOuter Diameter in.Wire Diameter in.Overall Length in.Rate
lbs./in. of travel
Load lbs.Material
C20-045-0400.6000.0451.2508.007.73MUSIC WIREPricing / Order
C20-049-0400.6000.0491.25012.809.1MUSIC WIREPricing / Order
C20-055-0400.6000.0551.25018.5012.6MUSIC WIREPricing / Order
C20-059-0400.6000.0591.25023.9015.3MUSIC WIREPricing / Order
C20-062-0400.6000.0621.25030.5017.5MUSIC WIREPricing / Order
C20-067-0400.6000.0671.25035.0021.7MUSIC WIREPricing / Order
C20-072-0400.6000.0721.25045.0026.5MUSIC WIREPricing / Order
C20-080-0400.6000.0801.25082.0035.4MUSIC WIREPricing / Order
C20-085-0400.6000.0851.250107.0041.8MUSIC WIREPricing / Order
C20-091-0400.6000.0911.250154.7050.3MUSIC WIREPricing / Order
C20-100-0400.6000.1001.250203.0064.9MUSIC WIREPricing / Order
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Old 11-05-2013, 07:44 AM   #19
motobene
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I'm puzzled about the 'bigger' master cylinder comments. There is a similar idea with the HRC 4RT with riders spending money on a 'larger' master cylinder with exact same piston diameter and lever ratio and perhaps just a larger reservoir. this does not affect lever pull, clutch quickness, etc. It just lightens the wallet and a psychological effect of it working because money was spent. If a larger master cylinder piston diameter is used, it increases force, not decreases it.

Here is a summary of what reduces lever pull with hydraulic clutches (I may forget some:

- Lubricating the lever pivots and contacts

- Setup for better ergonomics like:

- Moving the master cylinder inboard some to run the index finger farther out on the lever (adjust the lever stop and engage point accordingly)

- A master cylinder with a smaller piston diameter (if it's already 9.5mm you'll have no alternatives)

- A larger slave cylinder diameter

- Reduction in preload on the clutch springs (just a little reduction multiplied by all springs is significant)

- Removing two springs on a 6-spring clutch

- Fitting some or all clutch springs that are softer = smaller wire diameter, slightly larger outside diameter and more turns in the coils

- Rider skill level

The last point is indirect of course, but some riders wear out their arms more quickly that others. This isn't a man-up comments, but just stating the perhaps un obvious.

I've noticed a correlation between complaints of arms and hands wearing out and rider skill level. As skill level goes up, the body and legs become more dynamic and forceful, and arm and hand inputs become more brief and pulse-like. While more advanced riders tend use the clutch often and more, the arms are relaxed much of the time. More correct body position for turning, for example, results in a little palm pressure, thus reducing the need to clamp onto the bars. Initiating turns more with the legs reduces arm force a s well.

Did I miss something?
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Old 11-05-2013, 07:56 AM   #20
motobene
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Quote:
Originally Posted by Luke View Post
A couple of thoughts:

How about taking some stock springs and cutting coils off them? It'll make the spring rate higher but the force will be lower because the preload will be less.

Or, how about industrial spring suppliers?

Google brought up an ad for these guys: http://www.springsfast.com/
They have lots of available springs.

I guessed 0.6" od x 1.25" long and got these:

Part NumberOuter Diameter in.Wire Diameter in.Overall Length in.Rate
lbs./in. of travel

Load lbs.Material


C20-045-0400.6000.0451.2508.007.73MUSIC WIREPricing / Order
C20-049-0400.6000.0491.25012.809.1MUSIC WIREPricing / Order
C20-055-0400.6000.0551.25018.5012.6MUSIC WIREPricing / Order
C20-059-0400.6000.0591.25023.9015.3MUSIC WIREPricing / Order
C20-062-0400.6000.0621.25030.5017.5MUSIC WIREPricing / Order
C20-067-0400.6000.0671.25035.0021.7MUSIC WIREPricing / Order
C20-072-0400.6000.0721.25045.0026.5MUSIC WIREPricing / Order
C20-080-0400.6000.0801.25082.0035.4MUSIC WIREPricing / Order
C20-085-0400.6000.0851.250107.0041.8MUSIC WIREPricing / Order
C20-091-0400.6000.0911.250154.7050.3MUSIC WIREPricing / Order
C20-100-0400.6000.1001.250203.0064.9MUSIC WIREPricing / Order
Given the end of the springs is a bit coil bound, decreasing preload by grinding will have a positive effect. But unless you have a very good belt sander, grinding springs can be a royal pain. If you heat the coils up to orange, which can happen fast, you take heat treat out of them and the heated up part of the coil can collapse.

As for trying other springs, if you can find the near equivalents, why not? In the table they give you k in pounds per inch, so you know stiffness. You'll need not just springs but those that have ground ends so they don't cock on an angle when preloaded.
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Old 11-05-2013, 09:03 AM   #21
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Quote:
Originally Posted by motobene View Post
Given the end of the springs is a bit coil bound, decreasing preload by grinding will have a positive effect. But unless you have a very good belt sander, grinding springs can be a royal pain. If you heat the coils up to orange, which can happen fast, you take heat treat out of them and the heated up part of the coil can collapse.

As for trying other springs, if you can find the near equivalents, why not? In the table they give you k in pounds per inch, so you know stiffness. You'll need not just springs but those that have ground ends so they don't cock on an angle when preloaded.
Yup, as the springs are Square End, effectively coil bound on ends, considered putting to belt sander, watching that they don't go cockeyed. Industry friend said will simply measure rate of OEMs and source some lighter ones.
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Old 11-05-2013, 10:31 AM   #22
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Originally Posted by motobene View Post
Did I miss something?
Since you asked.

In GG's - Dot 5 (silicone based) clutch fluid will help reduce seal stiction and friction and have a small but noticeable overall effect on lever pull. I would assume that this may also be noticeable in other designs.
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Old 11-05-2013, 10:52 AM   #23
StuInFH OP
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Laugh

Quote:
Originally Posted by motobene View Post
Did I miss something?
Good point on MC sizing, will follow up to see what was actually changed for those pros.

My mistake for posting this on Trials forum. After 45+ yrs riding offroad/mx/street/etc. and now trials (for four relatively short years), I know a little bit about arm pump causes and cures (and admittedly nothing about fluid mechanics, which is magic to me). (BTW, when was the last time you heard of a (now smaller) mx pro getting surgery to his forearm muscle sheath? hmmm)

I guess I wasn't clear enough that I'm setting up my Scorpa for hard enduro riding, i.e., racing buddies thru the tough stuff, like Little Sluice on Rubicon. Think EX stuff. Not trackstanding in a short section. Inarguably, EVERYONE that does that type of riding can benefit from a lighter pull. Or even an auto clutch like sissies use, like on my girlie KDX.

Anyone know the part number for lighter springs?

JK, the answer is obviously no, so I will measure the OEMs and source some myself. If anyone wants the PN/source info later, let me know. I can hardly wait to say Man Up!
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Old 11-06-2013, 07:23 AM   #24
motobene
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Originally Posted by StuInFH View Post
Good point on MC sizing, will follow up to see what was actually changed for those pros.

My mistake for posting this on Trials forum. After 45+ yrs riding offroad/mx/street/etc. and now trials (for four relatively short years), I know a little bit about arm pump causes and cures (and admittedly nothing about fluid mechanics, which is magic to me). (BTW, when was the last time you heard of a (now smaller) mx pro getting surgery to his forearm muscle sheath? hmmm)

I guess I wasn't clear enough that I'm setting up my Scorpa for hard enduro riding, i.e., racing buddies thru the tough stuff, like Little Sluice on Rubicon. Think EX stuff. Not trackstanding in a short section. Inarguably, EVERYONE that does that type of riding can benefit from a lighter pull. Or even an auto clutch like sissies use, like on my girlie KDX.

Anyone know the part number for lighter springs?

JK, the answer is obviously no, so I will measure the OEMs and source some myself. If anyone wants the PN/source info later, let me know. I can hardly wait to say Man Up!
I hope no mistake posting here! In the non trials, refrigerator bike, floppy-back bars-in-lap forum areas your trials/Scorpa question could be viewed as alien and utterly weird, and leaving the fold

I came out of Expert Cross Country Racing and know the fun you're seeking. I've had some big fun pushing a trials bike as fast as possible in tight, gnarly woods and other nasty 2 track. It's a hoot to eat up the guys on refrigerator bikes in the tight and nasty, but then we get dusted when the nasty opens up to big sand whoops. Oh well. I'm no longer into maximum fast in the open. Just too risky to life and limb.
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Old 11-06-2013, 09:50 AM   #25
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Originally Posted by motobene View Post
I hope no mistake posting here! In the non trials, refrigerator bike, floppy-back bars-in-lap forum areas your trials/Scorpa question could be viewed as alien and utterly weird, and leaving the fold

I came out of Expert Cross Country Racing and know the fun you're seeking. I've had some big fun pushing a trials bike as fast as possible in tight, gnarly woods and other nasty 2 track. It's a hoot to eat up the guys on refrigerator bikes in the tight and nasty, but then we get dusted when the nasty opens up to big sand whoops. Oh well. I'm no longer into maximum fast in the open. Just too risky to life and limb.
I know you can ride.

http://www.youtube.com/watch?v=Cp3m6...layer_embedded EX on TBs at 2:17. Inmate/narrator is funny. Looks like fun event w/o neck-breaking speed. Couple club members rode the one in Sac, one on his TB, other on his enduro. Toying with the idea myself before way too old, only a bit too old right now. Need to practice more, but got the bike and the whiskey throttle part mastered already. Cheers
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Old 11-06-2013, 10:16 AM   #26
motobene
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Quote:
Originally Posted by StuInFH View Post
I know you can ride.

http://www.youtube.com/watch?v=Cp3m6...layer_embedded EX on TBs at 2:17. Inmate/narrator is funny. Looks like fun event w/o neck-breaking speed. Couple club members rode the one in Sac, one on his TB, other on his enduro. Toying with the idea myself before way too old, only a bit too old right now. Need to practice more, but got the bike and the whiskey throttle part mastered already. Cheers
That was great narration! "Then it was our chance to ride..." I had a good laugh. Trials is great for face planting the ego.

If I was younger I'd be right there doing Endurocross on some 'refrigerator' bike. But alas, I value my delicate parts these days....
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Old 11-06-2013, 10:21 AM   #27
motobene
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Originally Posted by laser17 View Post
Since you asked.

In GG's - Dot 5 (silicone based) clutch fluid will help reduce seal stiction and friction and have a small but noticeable overall effect on lever pull. I would assume that this may also be noticeable in other designs.
Thanks. I've wondered about this. Somewhere may be tech data on the effect specific oils have on the static and dynamic friction coefficients between various materials.

How much is assumption and how much real? I wish I had a Chatillon gage to do before-after force testing.

I should try the Dot 5 for direct experience. Have tried the OEM low viscosity mineral oil, higher viscosity mineral oil, mineral oil and ester based shock fluid. I should pull the primary cover off and do a full exchange by forcing Dot 5 bottoms-up by filling the top hat (piston).
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Old 11-06-2013, 11:33 AM   #28
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All I can tell you is that I tried it and noticed it. Im also a perfect candidate for the placebo effect!
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Old 11-08-2013, 08:02 AM   #29
motobene
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All I can tell you is that I tried it and noticed it. Im also a perfect candidate for the placebo effect!
And confirmation bias
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Old 11-08-2013, 09:06 AM   #30
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And confirmation bias
Absolutely! Especially when someone like John Stoodley is behind it.
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