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Old 01-28-2008, 10:28 AM   #76
Dr. Love
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Quote:
Originally Posted by NC Rick
Check your sag now, look for the 3.5-4" of sag (about 30% of your travel) and see how much unloaded sag you have. If the unloaded sag is a small value (say 1/4 inch) then your spring is too soft, if on the other hand it is a big value (like 2 inches) your spring is to stiff.
Probably nit-picking but doesn't 3.5-4 inches of sag on the DR650 correspond to 34% - 39% of total travel?
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Old 01-31-2008, 07:03 AM   #77
NC Rick
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Sorry for being so slow Dr Love. You are correct of course! While the often quoted recommendation is 30-35% of travel (10.2 on our beloved DR 650). There isn't a real hard and fast rule. 100 mm or about 4" is often used on dirt bike rear suspension as a starting point. At the end of the day, rider preference has a lot to do with it. I personally like the bike with a good bit of sag at the rear, it just feels better to me. 4" feels much better than 3" and makes the bike a little lower (I am close to 6'2"so this isn't a BIG deal but I like reaching the ground on those side hills).

I would love to hear what springs/ vs sag/ vs free sag some of you folks are running.

Here is a photo of the DR shocks I have (ready for anodizing) from this past Monday:
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Old 01-31-2008, 09:40 AM   #78
meanstrk
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Sweet! Which one is mine?

Any estimated completion date on these Rick?
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Old 01-31-2008, 10:37 AM   #79
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Quote:
Originally Posted by NC Rick
I would love to hear what springs/ vs sag/ vs free sag some of you folks are running.
I sent you a PM regarding sag but maybe someone else can answer.

I'm awaiting an aftermarket tank and a few other bits. Once I get everything, I need to measure my sag to see where I'm at with springs and preload adjustment.

I'm trying to measure the sag myself. I rigged up a way to measure it using an allen wrench, duct tape, curtain rod, zip ties, and a marker.

It would be a little easier to measure the race sag if I could use a rear stand like a pitbull. My question is, will it throw off the measurement? Is this a no no when measuring sag?
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Old 01-31-2008, 11:57 AM   #80
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Meanstrk, Yours is next to the second one from the center

Eugene,

Sorry I missed your PM I don't get many on here. I happen to be very well prepared to answer that question because I was just doing the same thing myself. You can use a rear stand providing the rear stand supports the swing arm as close to the axle as possible and you also block up the front wheel by the same amount of clearance you end up with the rear wheel being off the ground by. Having the bike on an angle noticeably alters the weight bias and thusly the sag measurement. My friend made himself a paper scale and used a laser pointer to hit it.
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Old 01-31-2008, 12:20 PM   #81
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Quote:
Originally Posted by NC Rick
Meanstrk, Yours is next to the second one from the center

Eugene,

Sorry I missed your PM I don't get many on here. I happen to be very well prepared to answer that question because I was just doing the same thing myself. You can use a rear stand providing the rear stand supports the swing arm as close to the axle as possible and you also block up the front wheel by the same amount of clearance you end up with the rear wheel being off the ground by. Having the bike on an angle noticeably alters the weight bias and thusly the sag measurement. My friend made himself a paper scale and used a laser pointer to hit it.
Thanks Rick.
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Old 02-01-2008, 07:50 AM   #82
meanstrk
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When are you looking at shipping the finished shocks back out? I get back from CA late Sunday!
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Old 02-03-2008, 01:28 PM   #83
Eugene
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I measured my sag today to get a reading before I add an aftermarket tank. The bike has all stock suspension and a full tank of gas. The only add on bits are a Corbin seat, rear rack, and dirt bagz racks. I should have put on the stock seat and taken off the racks to get a completely stock reading but didn't think about it until after I was done.

I weight right around 160lbs and I wasn't wearing any gear.

Rear:
Static: 45mm(1.77 inch)
Race: 93mm(3.66 inch)

Front:
Static: 37mm(1.46 inch)
Race: 62mm(2.44 inch)

The front seems to be way off. Does this sound right??

As for the rear, I haven't made any changes to it. I bought the bike used and I've only had it for a little while. I knew I was going to do something to the suspension so I haven't touched the preload. By the looks of it, my preload is cranked up?? It's somewhat close to the end of the threads. I'm a dummy when it comes to suspension. If it's cranked up, what will it do to my readings if I take it the other way? I'm trying to get a better understanding on the spring rate. Here's a pic:

Sorry for the big picture.

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Old 02-05-2008, 08:10 AM   #84
meanstrk
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Yep. Your preload is cranked up pretty high!
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Old 02-07-2008, 09:57 AM   #85
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Measure the sag from a point vertical above the rear axle. A spot on the fender or frame will do. Unweight the bike by lifting the rear till the suspension tops out. have your assistant measure to the spot from the axle. (you can do this on a stand) then let the full weight of the bike (with gas) settle on the spring. measure again to the same spots. Subtract the smaller # fron the larger#.This is static sag. Sit on the bike (with riding gear) both feet off the ground. Measure again. Subtract the new measure from the original measurement with bike unweighted. this is race sag. If race sag ,3.5" - 4.0" or so can't be reached with a static sag of approx 3/4" you will have to get a different spring. Keintech can tell you which will work best in your application. Luggage and larger fuel tanks may have to be considered.
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Old 02-07-2008, 03:09 PM   #86
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Quote:
Originally Posted by Rusty Rocket
Measure the sag from a point vertical above the rear axle. A spot on the fender or frame will do. Unweight the bike by lifting the rear till the suspension tops out. have your assistant measure to the spot from the axle. (you can do this on a stand) then let the full weight of the bike (with gas) settle on the spring. measure again to the same spots. Subtract the smaller # fron the larger#.This is static sag. Sit on the bike (with riding gear) both feet off the ground. Measure again. Subtract the new measure from the original measurement with bike unweighted. this is race sag. If race sag ,3.5" - 4.0" or so can't be reached with a static sag of approx 3/4" you will have to get a different spring. Keintech can tell you which will work best in your application. Luggage and larger fuel tanks may have to be considered.
You don't approve of my duct tape, curtain rod, hex wrench, zip tie method?
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Old 02-07-2008, 03:28 PM   #87
Rusty Rocket
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Quote:
Originally Posted by Eugene
You don't approve of my duct tape, curtain rod, hex wrench, zip tie method?
Frankly, I woke up screaming!!
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Old 02-08-2008, 05:47 PM   #88
NC Rick
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Man, I have had my hands full here guys. I have not been able to keep up with this thread. Eugene, don't worry about how many threads are left on the shock, can you check what the installed spring length is? since you have your sag set you have plenty of threads left and I don't think you have that much preload. The minimum I have seen is 250 mm installed length.

Check this afternoons photo:

I did not hat time left in the day for shipping. Rons spring is white
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Old 02-08-2008, 05:56 PM   #89
neepuk
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I want in on the next build. PM coming.
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Old 02-09-2008, 07:04 AM   #90
NC Rick
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I need to get the shocks for the next run coming. I would like to have them by late next week. Depending on when they get here, a two week turn around is likely (it could be a little better). Please get with me quickly if any of you would like to be part of the next built. I have 2 more to put together from this first build. a couple others are shipped.

Eugene's sag is close on the rear but the unloaded sag is too much, indicating a stiff spring. Also by PM I found that the spring preload is only at about 8mm. For a spring of that length we would expect to see 15-20 mm preload. All that is is another indicator of the spring rate.
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