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New Springs, now I'm drivin a chopper..

Old 04-01-2006, 09:43 PM
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New Springs, now I'm drivin a chopper..

Ok, guys, I just had a set of 1.0 KG springs put in, and now when I ride it feels like I have a pogo stick for a front end. The handling is all wrong, it wants to drop into turns, it seems like the front end is sitting drastically higher than it was, you get the idea. .

I know this is normal given the new springs, but now I have to adjust things so the bike handles like it should. It seems like the obvious step would be to raise the forks in the triples a few mm, but I am wondering if this is the best way to fix this. My adjusters are backed out all the way right now, so if I don't lower the front, it seems like I will either have to raise the back end [not a good choice, I have a short inseam] or shorten the spacers [unknown side-effects]
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Old 04-10-2006, 04:07 PM
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Did you cut the spacers to start? I'm getting the opposite feeling from mine... I need to do fork springs pretty badly. It feels like its wallowing all over the place. I'm in the process of losing weight, but the bike being set up for a 120#er does me no good, since my goal is 175 (down from 193)
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Old 04-10-2006, 05:50 PM
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Re: New Springs, now I'm drivin a chopper..

You can raise the forks up in the triple clamps to compensate. I did that rather than dick around with the spacers which I cut to match the stock setup more or less. Since the springs were a different length I cut the spacers to approximate the existing setup, which resulted in the same results you got, pogo time.
It was rectified by raising the fork legs up in the clamps by about 5/8 of an inch, and voila it was perfect.
I used 90kg springs, and I weigh about 180, not counting today's tortallini dinner.
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Old 04-10-2006, 06:56 PM
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Re: New Springs, now I'm drivin a chopper..

Uh.....
Did you follow the instructions that came with the springs?
I assume you have Race Tech springs.
THey come with good instructions.
Setting up the overall spring and spacer length is critical.

Also....
You should match the compression and rebound valve shims to match the new springs or it will "pogo" on you with the stock shims.
There is a BIG difference from the stock .58kg/mm and your new 1.0kg/mm springs so you have to reshim the valves so they are not overpowered by the stronger springs.

And....
Last the oil heigth is different from the stock when you modify the forks like that.

Sounds like you have some more fork internals work to do before you start changing the bikes geometry by lowering the front and/or raising the rear.
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Old 04-10-2006, 08:29 PM
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How much do you weigh Barry? Did you follow the directions completely and correctly?

BTW, Hydraulic fluid is not compressible. It will not flow through the cartridge more quickly no matter how strong the springs are.
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Old 04-10-2006, 09:44 PM
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Re: New Springs, now I'm drivin a chopper..

Instructions? I took the bike and the springs to a shop, along with my SS lines, and Viola, 2 weeks later I have a fixdid bike... I did not do any of the setup, nor did I have any input into it [other than buying the springs]

I am 240 buck nekkid, [plus gear]
The 1.0kg Springs are a compromise, lighter than was called for on the track, heaver than the street...
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Old 04-11-2006, 08:32 AM
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Barry,
How much static sag do you have? With a friend, measure the difference between the fully extended (front wheel off the ground) length, and the length with you on the bike (preferably suited up). The bike should sag about 25mm in the front and rear as a good baseline. This will give the bike the as-designed geometry.

As far as damping goes, CNIDawg is right, the valving needs to be matched to the spring rate. It's not a matter of compressibility ( ??). The valving adjusts the proportionality of damping force to suspension velocity. Springs determine force dependent on suspension position. They should be tuned together.
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Old 04-11-2006, 09:36 AM
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Re: New Springs, now I'm drivin a chopper..

Originally Posted by barrysuperhawk";p=&quot View Post
Instructions? I took the bike and the springs to a shop, along with my SS lines, and Viola, 2 weeks later I have a fixdid bike... I did not do any of the setup, nor did I have any input into it [other than buying the springs]

I am 240 buck nekkid, [plus gear]
The 1.0kg Springs are a compromise, lighter than was called for on the track, heaver than the street...
You're right, those are the right ones for you. I guarantee you they didn't trim the spacers to the proper length. They just pushed them in.
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Old 04-11-2006, 10:13 AM
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Re: New Springs, now I'm drivin a chopper..

Originally Posted by jschmidt";p=&quot View Post
You're right, those are the right ones for you. I guarantee you they didn't trim the spacers to the proper length. They just pushed them in.
ARGH !!!
I hate it when you can't get the work on your bike properly done!!!!
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Old 04-11-2006, 11:59 AM
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Re: New Springs, now I'm drivin a chopper..

Barry,

I just put my .95 springs in during a rain braik two weeks ago.
Due to time constraints (the next flood rain approaching) I opted to reassemble using the original spacer (un-cut) so I could get back home before "Noah’s ARK" started backing up traffic.

The difference in spring length between the RT springs and stock was about 2 inches. This raised the bike about 2 inches in the front and definitely affected handling with the chopper stance and stiffer springs. I think you may find the folks who worked on your bike did not cut the spacers either properly or at all. As mentioned earlier, before changing your bike's geometry make sure the springs, spacers, oil level... are correct.

If you got the RT set up I can send you a copy of the instructions by this week end if you want via email or fax. I have to go get them at the shop.

You will need to get all the weight off the front end before opening up the fork caps.

I did not have a bench available to set the bike on so I used a front end stand that lifts with a pin under the triple clamp.
Two people is advised here so the bike doesn't flop over.
Then I used various wood blocks on both sides of the bike near the engine cases and swing arm to keep the bike solid and straight since I did not have a rear stand.

Fooling with the fork height at this point will only mask a problem that will come back to haunt you at the worst possible time.
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Old 04-11-2006, 01:12 PM
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If you can get the bike to sag off the top stops at all with your weight on it, you'll know how much to change the spacer lengths. Spring rates are different so you can't use use the spring free length as a reference.

Try to get your spacer length so that you have the right sag at near the middle of the adjuster range.
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Old 04-11-2006, 01:16 PM
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If you follow the Racetech directions exactly, and you're 235 lbs, you will get proper sag in the middle of the range. 240 should be no diff Its uncanny how accurate they are.

BTW, I did just the springs (same springs, same weight, RT recommended fork oil but 10mm below RT height) and the difference was transformative.

That's why I think you have an installation error.
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Old 05-06-2006, 05:25 PM
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Re: New Springs, now I'm drivin a chopper..

My racetech springs were about 1.5 inches longer than what was in the bike before (stock progressive spring?), and the included racetech spacer was about 4 inches long. I thought my spacer was aluminum, the stock one was steel. There was no way to install the new spring if you didn't cut the spacer down. I cut the racetech spacer so the combined length matched the stock spring/spacer length, figuring this would be a good conservative start. With the new spring/spacer the correct sag takes about 1/4 of the preload (where before I was almost at full preload).

At first this + overall higher ride when braking made the bike feel a bit chopperish to me, I wanted to lower the front but now I'm used to the change. It doesn't really affect how I ride, I just push the bars a little harder to turn. Note the higher fork makes the bike more stable, less likely to "flop" into turns. Before the bike was skittish when braking because it was bottoming.

I don't think the shop could have put the springs in with uncut spacers, it'd be quite a challenge to get the forks back together like that. The resulting forks would have no sag.

If I were you I'd start from scratch. Measure sag and height of the fork, compare with what its supposed to be, then setup spacer length and preload, then rebound. Get it setup according to the shop manual. Don't mess with fork height in triple clamp until everything else is right.

Also consider that the shop might have dropped something down the fork legs.

Alternatively, take it back to the place that did the work and yell at them, or avoid the trouble and find a different (good) mechanic to do it for you.
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Old 05-06-2006, 09:19 PM
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Originally Posted by zakthor";p=&quot View Post
I don't think the shop could have put the springs in with uncut spacers, it'd be quite a challenge to get the forks back together like that. The resulting forks would have no sag.

find a different (good) mechanic to do it for you.
Where there is a will there is a way. :wink:
You can install the RT springs with stock uncut 4" spacers.
It takes 2 people and A LOT of force.
You are correct on there not being any sag.
Desperation will make you do strange things.

I have since had some time to make some adjustments to the spacer length. Currently 39mm was removed (1 1/2" aprox). Still dialing in to my taste.

I heard a saying recently that goes like this:
"If you feel trouble in the rear...work on the front"
"If you feel trouble in the front...work on the rear"
This seems to be holding true as the work I do to the front has significantly changed how I perceive the rear to be reacting.
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