rcvtr,

I've been measuring from underside of triple to ties around fork. Actually, you just made me realize something. I measured to the metal edge for the full extension and to ties for the others. This would probably make that about 5mm to long. I better edit the message for greg.

My ref to the chin fairing bolt was something I read from greg as a measuring point for ground clearance because i was trying to see the height differential front and rear relative to OEM so I could imitate the similar geometry or at least understand the new geometry in case of handling issues.

thanks, Nathan

 

Nathan;

If you have the fork caps on you have at least "some" preload. You'd need to crank down to one line showing or whatever it was on when you measured with the shorter spacers. That's the only way to determine what difference the longer spacers make.

 

RK,

yeah, there is a lot of preload judging by how much I had to push down and hold while trying
to get the caps to thread; and the longer spacers used up almost all the threads before the rebound rod seated. The lock nuts were only a couple threads up from the smooth rod section. I was starting to wonder if I went a little to long on the spacers.

full extension changed to accommodate fork seal in lieu of metal rim below it(5mm)

these are more accurate:
full extension=137mm

stat sag=124mm

weighted sag=101mm

137mm-101mm=36mm

no preload or rebound adjusted in yet.

thanks, Nathan

 

Okay, give yourself 3 lines of preload, such that the 4th line is even with the fork cap. That should put you right at the sag values I posted earlier. That is the way I set up forks, so that the sweet number is right in the middle of the adjustable range. That way the rider can tweak +/- 5mm to his/her liking.

 

For those baffled by the content of this thread, this should help put it in perspective:


;http://www.youtube.com/watch?v=Watf8_Rf58s

 

You are right on with this one. Difficult to explain/comprehend without writing a book with illustrations, or a video demonstration because of so many different levels of competency and terminology and procedure variables:

for example, using tie on fork to measure

static(unladen)sag:

1)pull up clip-ons and let drop easily with tie against fork seal, then measure from under triple clamp to bottom of tie.
2)push down on clip-ons and hold, slip tie down to fork seal, then slowly release. Measure from under triple clamp to bottom of tie.
3)average two results

complicated to describe but very easy to understand on video or pics.
the procedure is easy once you understand and do it many times, but then understanding why you're doing what is a whole different story.

I have a shop manual, but it really doesn't explain ****. better than nothing, but not great...
that's why people like me need help and this is understandable for the untrained. But most would be surprised at how many professional bike mechanics that charge the big bucks still resort to replacing parts and really don't understand how things work and more importantly how they all interact together. those who do know are rare individuals indeed.

Thanks to those like Greg, yourself and others for being so patient and diligent.I'm slowly learning just enough to be dangerous.

Nathan

 

You said one very true thing at the end there... "Im learning enough to be dangerous..." not a direct quote... I'm lazy... But I think that's true for us all... The more we know, the more we realize what we don't know...

All on different levels, but all very true... And that's why I like this place... We all share, compare and discuss at our level of knowledge... And more often than not we all end up learning something even the more knowledgeable ones...

 

that's probably true, but how would you know about the knowledgeable ones.............................just kiddin'

seriously, this forum is great and the combined experience is an invaluable resource that would be impossible to duplicate in any other way.

One of these days there will be a whole new dimension to this forum. We'll be using video conferencing technology, showing, describing, and discussing and havin' a good old time.

thanks, Nathan

 

Greg,

maybe a little too much preload now, probably because I screwed up on extended measurement--dam, I'm having a hell of a time with extended(first time, neglected to account for dropping front end, now for the seal). didn't adjust for the fork seal width.

4th line even with fork cap

132mm extended length(from trip clamp to top of fork seal)
117 unladen
112 laden
132mm-112mm=20mm sag

5mm difference between laden and unladen
20mm sag



thanks Nathan

 

Why would you have to account for dropping the front end (raising the fork tubes in the triples)? That will have a marginal effect on sag, 1-2mm at most.

Did you read the knowledge base article on setting sag?

 

Yeah, Greg, but I don't think that's the problem.

I knew something was wrong from the get go and I think I've figured out what it is. He measured full travel/full extension BEFORE he raised the forks 11mm. And I don't think he was measuring sag by marking the tubes- lifting the front and measuring from top mark (sag) to the bottom mark (full extension).

He was subtracting after taking all his measurements from the bottom triple clamp down. Since he kept using the 11mm too large number for full extension- he ended up with an 11mm too big number for sag after subtracting.



That explains why he had such a larger sag # than I did with the same spring weight and spacer length.

Nathan, I think you should trim about 11mm off of the spacers and you're good to go. That will give you spacers about 2mm longer than mine for the same sag. Since you weigh about 20 lbs. more than I do, this finally makes sense to me.

PS if the previous spacers were actually 70mm and you just put them back in and cranked the preload to 2-3 lines showing, you'd probably be close to perfect!

 

i don't know why the measurements were wrong unless I had the bike off the ground with the springs out, cap/rod disconnected? am I the worst student you ever had?

yesterday ,70 degrees, wow! riding time. I set the preload back to 6 lines showing:

extension 132mm
average unladen 118mm
laden sag 106mm
132-106 = 26mm sag

at the end of ride, plastic tie on fork revealed that there is only 30 mm of travel remaining before the seal would be hitting triple clamp. i don't understand how the fork guard didn't hit the the bolt or something on the triple clamp. How much is clearance allowable here? oem fork travel is 4.3", mine is 132mm -30mm or 102mm fork travel, so far anyway.

the front end felt way better over rough back roads. dam winter gravel had the *** end out a couple times-scared the bejesus out of me.

I took some more measurements, ah-oh, to see what kind of ground clearance I had with this set up because the bike felt pretty well balanced.

OEM clearance i assume at lowest point, i.e., pipe?

pipe oem=5.1"
pipe now=5.75"
height increase=.65"

seat height- balanced bike up straight, 3' level on seat 12" back from tank?

seat height oem=31.9"
present seat height=32.5"
increase=.60"

front 11mm drop
rear 6mm shim

I don't know, but I'm psyched. going to put another 100 miles or so today.

thanks, Nathan

 

you're probably right RK. i've done so many measurements lately, i'm forgetting how I measured what and from where. Give me a rule and something to measure and look out.

yeah, the first spacers i cut were 70mm and now there at 83mm. if my front/rear height measurements are in the ballpark, the bike seems to be near a good balance between front and rear height/clearance. If I cut the spacers back to 73mm, and if my ground clearance measurements are accurate, I'll probably take a shim out of the rear. It's different being up so high, which i don't mind, except throwing the leg over the seat cowl to get on requires a little more stretch. Also, so far , with only a 100+ miles of all types of roads, the increased height seems to highlight the need for other mods like a fork brace and/or a steering stabilizer, and a better shock.

I'm going to ride more today.

thanks, nathan

 

You have now told us that the fork travel is 152mm, 142mm, 137mm and 132mm. You have told us that the shock spacer is 6mm and you've said it is 4.5mm.

Consider doing yourself a big fat frickin' favor. Stop measuring, figuring and calculating before you go insane.

Put the 70mm spacers back in the fork tubes, crank the preload adjuster down to the third line just barely showing. Take the bike for a ride. If the front feels low/rear feels high, pull out the shock spacer and go for another ride.

 

you're right RK. i'm sorry. i know you're really trying to help and I'm doing the best I can to learn. Tell me this. if you have no springs, rod, or cap in the forks, would the extension be different. If so, that's where I got the 152mm and that was to the metal. not the seal. I at first thought that this was a constant and would never need to be remeasured. I don't remember where I got the 142mm, but the 137/132mm difference came because I changed to the seal instead of the metal for more reliability. It would be a hell of alot easier if I had removed the fairing because i have to use reading glasses and i'm trying to read the rule sideways with the bifocals at the bottom and trying to hold a flashlight too.

relative to the 4.5mm/6mm disparity, I use fender washers for shims @ 1.5mm each and removed one for a short time and then put it back til I get the front sorted out.

again, I apologize for the confusion because I know you are trying to analyze the measurements to help me out.

thanks, Nathan

 

Yes, top out will be different. It's a wierd series of connections and is very difficult to explain. I tried writing it three times and ended up deleting it because it's that complex. Let's just say that the fork cap ties the whole thing together and keep it at that. Always take all measurements with forks fully assembled, WITH OIL, and installed on the bike.

 

I'm going through all of this soon.
I assembled my forks with 5mm of initial preload with the adjusters backed all the way off. That was just to be sure there was no slop between full extension on the main springs and contact with the top out spring.

I can't check unladen sag until I get all the pieces on. Then I have to figure out spacers.

 

FWIW;

Here is how I measured front sag. I don't know that it's the ideal way but seems simple and seems to work for me. If I'm overlooking or missing something let me know.

I have two friends help, one at the rear steadying the bike upright without pulling up or pushing down.

The other is at the front with a fine point magic marker.

I've got my feet on the pegs, *** on the seat and hands on the bars. I lean forward, push down on the bars and gently ease back to normal riding position.

I have front helper draw a line on the fork tube along the top edge of the slider.

I lean back while pulling up on bars then ease back to riding position. Front helper draws another line in the same manner.

I lift the front of the bike unloading the front wheel and measure from top edge of slider to the point midway between the two lines. That measurement is the sag.

 

That's about the same way I used... Also for unladen sag, push down and let it settle, then pull and let it settle... For this only one helper is needed though...

 

I'm starting over again. I put a few hundred miles on since there was a break in the weather. I was not happy with how the suspension felt, so I pulled the forks and triple clamps off. I found that the triple clamps were bent quite a bit on the left side(I'm not saying how much cause I don't want to rattle RK's cage).
I demo'd the bike a while back and put it back together. The left fork was bent pretty good but I didn't think the triple clamp was damaged since the new fork went right up in the clamp. Now I know better. Never had any handling issues. Anyway, I straightened the clamps, and put it back together again.
I'm thinking that the new springs lifted the front end up high enough to exacerbate the
problem, thus making it a bit tentative on faster bumpy turns, but I won't know til I ride it. I'm going to redo the sag(ah oh!), but I'm keeping the measurements secret.

thanks, Nathan

 

OOOHH, secret sag numbers!!

I guess you don't need us any more!

 

It isn't the sag # itself which must remain secret, but the precise method of measurement and formula for calculating sag.

The photo has been partially cropped to prevent this vital information falling into the hands of the terrorists who seek to destroy our way of life!

 

That's friggin hilarious, I don't care who ya are!!!

 

10-4......................Couldn't have been put better!

BTW I put the 70mm spacers back in the forks as per your suggestion and am starting over. Oh, I measured the first spacers again and they are really 72mm. Hah! I am consistently inconsistent, huh?

i wanted to put some graphics, smiley face types, but can't get them to show up, just records text. what's the deal?

thanks, Nathan

 

I'm no good at that graphical shiite either.

Sounds like you're wobbling toward the home stretch

Let us know how it works!

Ohh and BTW, that Einsteinian physics was just the ticket. LMAO!

 

hey, you got the smiley face on there anyway. i can even do that. I am a real squid.

I took the front fairing off to try to see if I could adapt a steering stabilizer I had from a gsxr. No dice-not long enough. Consistent with being a real squid, I didn't think to remove the front fairing the first time I was adjusting the sag and this time when removing the forks/triple clamps. the short time it takes to remove the front bodywork is well worth it when it comes to doing anything up front-so much easier and you can check everything out better.

fork specs: raised 10mm, .85RT, 72mm spacer, 4 lines showing=preload, rebound adjusted just enough to slow return.

extended 133mm
unladen sag push down 108mm
unladen sag pull up 118mm
average unladen sag 113mm
laden sag 103mm

133mm-103mm=30mm rider sag

are we in the ball park?
thanks, Nathan

 

I really think you'll find that a little harsh. That's on the extreme low end of the proper range. I'd set it to something closer to 40mm to begin with. I've found that to work pretty well for the stock forks on the street.

 

you may be right jd. i just removed fork spacers that were 11mm longer and had 26mm sag and that didn't bother me to much. i rode some rough country roads and you could definitely tell, but on smooth roads at higher speeds, didn't seem all that bad, other than the bent triple tree. Greg mentioned earlier I believe to shoot for 10mm unladen and 30mm rider. I was thinking i might have to crank a little more preload to get a better unladen number rather than the 20mm i have now.

i don't mind the suspension being a little on the active side unless it disturbs things mid corner on bumpy roads of which there are many here in the keystone state.

thanks, Nathan

 

You're not going to affect suspension rate much with sag #s. that has more to do with spring rate and damping rate. You can also control the suspension ramp rate with oil height. But you and I don't need to go there, yet.

With sag adjustment, it's more a matter of chassis attitude and keeping a load on the front tire when hard on the throttle. More sag will give you more travel when the front end is light.

I think Greg's point was, you want about 15mm of unladen sag, then if you get another 15 mm when you get on the bike, your spring rate is at a good starting point. If you get much more change than that, you might think about a stiffer spring.

Jamie's input sounds good. A bit more sag and a softer spring for the street since you won't have the cornering loads of a track bike. I guess that is a matter of personal preference.

at least that's my take on the whole sag thing.

 

Jamie, Nathan, and RCVTR,

My recommendation of 30mm sag is based on the forks operating in the upper third of the suspension travel. This generally gives better feel and suspension response and also allows sufficient travel for the occasional emergency braking maneuver. What you guys are missing is that Nathan's fully extended measurement is NOT the actual full stroke of the forks. The actual full stroke is 120mm, and this includes the oil lock travel, which is essentially useless. Nathan, I understand this may be a little advanced for you but try to stay with me. I don't mean to sound condescending but this is deep into the technical aspects of these forks and I'm trying to talk to three guys here.

So, the useful travel of our forks is about 100mm but we're going to ignore that and stick with 120mm. The upper third for a fork with a travel of 120mm is between 80 and 120mm. Technically, 40mm of sag is within that range but is pretty right at the low end and may cause bottoming on hard braking. 35mm is better, and generally a good number for the street. I like 30 because it allows that little extra margin.

The value of 40mm is useful for more modern forks with long top-out springs because those long springs actually raise spring rate at the top of the fork stroke (contrary to intuition). Our forks have short top out springs so this does not apply here.

Now let's discuss geometry. Bike geometry should not be determined by your preload setting. We went through all this trouble to select the correct spring and set sag so that your forks ride in the correct portion of the stroke. Let's leave them there! To alter bike geometry move the forks up or down in the triples and lengthen or shorten the shock using shims (or the adjuster if your aftermarket shock has that option). THAT is what changes geometry and leaves the fork settings where you want them (ignoring any small changes in weight distribution that might have occurred with the above).

Going more into suspension 202, based on experience with these forks, an internal preload of about 15mm will result in an unladen sag of about 10mm or so. This obviously depends on your spring rate but getting in the ballpark is all that's required. The unladen sag value of 10-20mm is based on having enough preload to A) get the desired laden sag value of 30mm, B) high enough to keep the spring compressed a small amount at full top out, C) low enough to prevent coil binding at full compression, and D) low enough to minimize topping out the forks regularly.

I hope this clears some things up for you guys. I don't want anyone to leave not fully understanding the goals and the proper way to achieve them. If anything is unclear please let me know.