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Discussion Starter #1
i know there has been a lot of talk about this and that there is documentation at zr-7.com but i still have a couple questions.

1) when they refer to a "PVC Schedule 40 end-to-end connector" i assume they are talking about a PVC pipe connector. (something easily found at home depot)

2) what diameter is the pipe? it clearly says that the length was about 1.75 inches, but i don't recall a diameter.

3) and just so i understand correctly, the pvc spacer goes in BEFORE the factory metal spacer, correct?

thanks!

josh (qheuie)
2001 zr-7s

btw. i bought oil and a filter today, my first solo oil change for the bike will be fun and probably messy!
 

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1) yes :)
2) crap, can't remember. it's just smaller than the outside diameter of the fork. pop the cap and measure if you want to be sure. or do what i did, buy a couple, they're less than a dollar.
3) yes. the order is spring, pvc spacer, stock steel washer, stock steel spacer.

scott :)
 

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Discussion Starter #3
went to the home depot, bought 1" and 3/4" pvc couplers. the correct size for the 2001 zr-7s (i would assume it is the same for all model, but i gotta put that disclaimer in there :) ) is.... 3/4"

i will be finishing off the "upgrade" and changing th eoil when i get home.
here's a little tip, (new to me) wrap tin foil around your exhaust down by the oil filter before opening it up, saves a bit of clean up and a lot of stink!

later,
josh
 

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I had the PVC spacer and a heavier weight fork oil put in by my dealership. I didnt notice much difference at all even when compared side by side with another ZR-7. Save your time and just pop in some progressive springs. Much more worth while.
 

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bikeguy669, i totally disagree.

i've got the unfaired 7, the 7s has stiffer stock springs. it would dive like hell under hard front braking, usually bottoming, and was really squirrelly in bumpy corners. i put in 3/4" pvc spacers and i'm about 180 pounds. i notice less sag when i sit on the bike, MUCH less brake dive (never bottoms now) and much better manners in bumpy corners.

i think the progressives and a change to 15w oil from the stock 10w would be a further improvement but just adding the spacers was a night and day difference. i've ridden this way for over 2000 miles and there most certainly IS a difference.

scott
 

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The Deer Slayer
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If I may, what's been done with the PVC trick is Pre-loading the front spring, right ? It makes it stiffer to begin with. But it doesn't give you the total package like a progressive spring.

The manual says too remove fork when working on it, BIG JOB ! We don't do that. We work with the fork on the bike. That's why its difficult getting old oil out. Who used the device to draw the oil out of the vertically positoned fork ?

Think I'll be putting in Progressive, they seem to make sence. Yes, loading down the spring leads to less wollow, but not better response. I want a better responding suspention.

Lastly, why can't forks have bleeders ? Wouldn't that make things easy? Is this not possible ?

Tony.
 

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Yeah Tony, you're right. All it does is preload the springs and takes out the slop. But it does add to them at a very minimal cost. The Progressive springs are progressive in the coils. The more they're compressed, the harder it gets to compress them.

And yes, Honda (an many others) use to put a drain bolt in the bottoms of the forks just for draining the oil. A person could probably do it by drilling a hole and tapping it for a plug. The big problem would be that you'd have to tear the forks all the way down so you could get all the metal shavings out so they wouldn't waste the seals. You'd also have to check the thickness of the fork legs to make sure that they are thick enough to get enough threads to hold the plug without blowing them out from the pressure. Other than that, piece o' cake.

One thing I've thought about trying is changing the caps on top and putting in air valves. Instant adjustment. It would only take a few pounds of air to change the ride.
 

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Discussion Starter #8
well, i put in the PVC spaecers tonight. just over an inch and a half. preliminary feel is ok. i think they may be a little stiff for me.
i think i am going to try 1" inserts. (if i can afford more parts! :laugh: )
i know that progressives would be "the" way to go eventually, but i figure i should at least give the inexpensive upgrade a try.
i also changed my oil (engine) and it sure sounds quieter (at least to me it does).
maintenance is fun :~
later,
josh
 

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The Commander
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Chris Mundell is the one who used the "suction" device to remove the oil from the forks while they were on the bike. Seemed to work great for him. Would someone PLEASE take some pics of the forks while you've got them torn apart so we could have some visual aids for the fork upgrade!!!!!! I'd like to do the PVC thing just to try it out, but I can't visualize at all what is involved. I need PICTURES!!!!!!! :D
 

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Discussion Starter #10
Jarel,
i am going to take my fork apart again to reduce the amount of "preload" i put in. i will get pictures when i do it. :D

josh
 

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The Deer Slayer
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Air shocks

Hummm, air shocks. Hey Martin, can you see yourself riding down the highway, front end bopping up and down like a hydraulic chevy impala ?:D Just a thought.

Tony
 

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Discussion Starter #13
actually, i think a properly designed air shock upgrade would work pretty good. i have been mountain biking for years and have seen lots of air suspension upgrades. yeah yeah, i know that mountain bikes are a lot diffferent thatn motorcycles, but they are quite similar..(most suspension technology for mountain bikes was originally stolen from moto)
i think the set up would just have to be beefier (obviously) but it would probably still be lighter than a spring set up.. hmm.. i better go to my google search!! ;)

later,
josh
 

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I've decided, with all the talk about it, that I going to try the PVC. It's that cheep thing I love so much ! What about fork oil ? Wasn't this covered once before ? Heavy oil better, right. But can you get all the old oil out without removal ? Sounds like a winter project.

Tony
 

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Discussion Starter #15
less than a dollar :)

as for the oil, couldn't you try to suck it all out with a big ol' syringe? you could probably get one from a farm store. just stick a long hose on the end and suck it out, right?
i would guess that if you don't get it completely "dry" that it would be ok.. you would just have a hybrid oil mix, wouldn't you? kind of like a mid-weight... hmm..
(that could be a big assumption based on Mt Bike experience)


josh
 

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qheuie and martin. air caps might work but you're going to be putting more load on the fork seals; they may blow out more easily. i worked in a mountain bike shop for a while and air forks are a real hassle. great when they work well but theyusually don't. the performance problem (stiction) doesn't apply here because we're dealing with more mass but the reliability issue does. they regularly leaked air and/or oil and often broke seals completely. no thanks.

med7, heavier oil isn't "better", it depends on what you wnat to accomplish. heavier oil is thicker and goes through the damping mechanism with more resistance so you get more damping. the shocks will react more slowly to bumps. lighter oil - vice versa. stock oil is 10 w and hyperpro sends out 15 w with their kit. some folks on this board who've installed hyperpro or pvc spacers along with 15w oil have reported good results.

i agree with qheuie, you don't have to get every last drop out. disassembling and cleaning the forks before you completely change the oil is great but you could use a syringe to drain them. you just have to try to remove as much oil as possible, remove the same amount from both sides and fill them to the same height when you're done. i think total oil capacity is around 500cc per side. if you get most of that out you're doing fine :)

scott :)
 

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A big mistake people make when dealing with air is they try to get as much in there to do the work of the spring. Not good. I use it just to assist the entire package. That's why I said before that it doesn't take very much to help the ride. It's just a cheap fine tune fix, not a replacement for what's there. Usually the more you ride, the more pressure will build. So I would probably go no more than 3-5 psi to start with, maybe less. It doesn't sound like much, but it's suprising how much that would help. Especially when there's not much there to begin with.
 

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that makes sense martin. i'm sure the seals could handle a few pounds since they probably already do just from routine compression. thanks for the clarification.

ok, more crap:
here's a link to how one guy changed his fork oil in his sv650 with a large syringe. yeah, i know we're supposed to hate this bike but i still think it's pretty cool and this guy has some good info.

http://www.svrider.com/tips/forkoildrain.htm

as martin already mentioned this doesn't remove any accumulated metal shavings or other junk. so if you're doing regular maintenance you should remove the fork legs and do it right but if you're doing a performance upgrade to thicker oil before the suggested service interval then this may suffice.

i also saw another good tip: when removing your fork caps use a six point socket instead of a twelve point socket. this is more friendly to those soft aluminum cap heads.

scott :)
 

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Discussion Starter #19
Jarel, i emailed some pictures of the fork mod to you.
Maybe you could post them (there are 4 or 5) somewhere for all to see ;)

scott.. i totally agree with the 6 point socket idea. i used the tool kit that came with the bike to remove the caps and it ate up the caps a little (and it is a 6 point) so i could only imagine what a 12 point would do to the poor things!

scott, tony, martin... i wonder if one could rig up an attachment to a shop vac (an old dirty shop vac :D ) to suck out the particles (and the last bit of oil) in the bottom of the fork? man, all these things to try!

later,
josh
 

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If the oil is thin enough you could put a longer suction tube on a solvent sprayer and pull it out that way, but then you'd have to figure out where to spray it. Or you could go with one of those syphoners. I still don't think you'd get it all out though. You'd probably be better off with the syringe.
 
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