new front fork problem

[ducatiz]

it really sounds like oil lockup

progressive springs are better on a cruiser/tourer not a sport bike, but that's not your problem. 

have you double checked the oil level?  valve function?

[ducatiz]

I feel for you mate. Sorry we're not nearby to come over with a few beers and help you out.

It really does sound like it could be oil "lock up" (hydraulic lock). Get some oil out to see if it improves. Take a fair bit out coz it's easier to put more back in than pulling those buggers off to take more out again!

use a syringe with a long tube.. snake it down the middle or on the side of the spring.  you can do it on the bike.

[ducpainter]

I have been working on the damn forks now for 2 years I have a notebook full of each adjustment running to 61 pages .I am now being told by other suspension gurus that progressive springs are what is causing my problem and to go back to the rubbish ducati linears springs ,.I test each mod on same road  . This aint science  its a black art ...hell i can write a powercommander map that works  without a dyno, rebuild scrap 8v heads that rock but these forks are something else?

Progressive springs suck.

The springs installed by the factory are probably wrong for your weight....and I believe were progressive also...at least the ones in my bike were.

How much do you weigh? Have you checked sag on your bike?

It only a black art because you don't understand it.

[scott_araujo]

It only a black art because you don't understand it.

Well said DP.  Some of the adjustment comes down to rider preference but you should be able to get into the ballpark by getting the right springs, sag, and an oil that is about right.  Then minor adjustments with some ride time in between will fine tune it.

Scott

[jerryz]

Half the Suspension experts say Progressive springs are the way to go the rest say linear springs are the way to go the standard springs in my S4 are linear and are great for comfort but lousy for handling, the Hyperpro springs are great for handling but lousy for comfort ...who is right?

.I have 2 years of testing and adjustments 61 pages of notes and ...No answers. Ha .

[ducatiz]

61 pages of notes?

but you are writing with a large crayon and it's a 2x3" notepad?



ok, seriously.  maybe it's time to start from scratch.  if what you've ended up with is wrong, using the same formula to "fix" it is just going to end up in the same place.

Maybe start with a full rebuild and inspection of the internals.  Do you have the original springs?  try using them again.

I'm anal, when I rebuild a shock, i leave it to drain over night so I can measure how much oil was in it.  When you refill it to the right level, use a graduated container so you can compare to the prior amount.

[ducpainter]

Half the Suspension experts say Progressive springs are the way to go the rest say linear springs are the way to go the standard springs in my S4 are linear and are great for comfort but lousy for handling, the Hyperpro springs are great for handling but lousy for comfort ...who is right?

.I have 2 years of testing and adjustments 61 pages of notes and ...No answers. Ha .

I believe linear springs are superior. The stock fork springs are too light for most riders, also the stock valve in the S4 forks is very stiff. It's called undersprung and overdamped. That combination will make for poor handling and a harsh ride. That was your complaint...correct?

You never said if you ever actually measured sag to determine if the spring you are using is correct, or correctly preloaded. You also haven't said how much you weigh. Believe it or not a stiffer spring will improve the ride quality.

If you're looking for supple and precise IMO you are going to have to upgrade to a racetech gold valve with a custom stack, and be certain you are running the correct spring. If you don't want to do that you'll have to accept the compromise of modifying oil weight and height to alter the damping. The correct spring is a must regardless.

So post up some actual numbers if you want help.

[scott_araujo]

That said, getting the right spring is the first step.  Different oil viscosities are the most inexpensive way to change damping but not as precise as adjustable suspension with custom shim stacks.

Scott

[jerryz]

I am going back to basics ...will re install standard ducati springs as i know they offer a comfortable and safe ride with 5w Motul fork oil , the handling is not super accurate but the bike is safe and usable . i will also drop the forks another 5mm and move the  the risers/bars  to 30mm forward  to get more weight on the front .I will play with that setup until April when the forks can go to UK and to PDQ developments for Racetech Gold valves and springs . The Hyperpro springs are going back to the dealer who recommended them.either for a refund or EBAY.

thanks everyone for all the input I will keep adding posts as the work progresses.

[jerryz]

The Hypepro springs are out now they have twice as many coils as the standard Ducati springs for the same length and virtually no give at the top progressive end ,that is the problem.

I will reinstall the standard springs for now with 5w oil and wait till i go UK and take the forks to PDQ  in UK for racetech revalve and linear correct weight springs.

Oh yeah spoke to the Surrey dealer who sold me the Hyperpro springs and he has refused a refund ...dirrrr he says they use them on Raceteam bikes and they are good .He was really patronising and rude so now they have lost a good customer who spent over $1700 last year on spares in their shop.
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MONSTERMAN

[ducatiz]

Photograph them next to the stock springs or bring them both in and talk to him again?  Maybe the springs were mislabeled.

[jerryz]

Photograph them next to the stock springs or bring them both in and talk to him again?  Maybe the springs were mislabeled.

OH I will ..its only fair,  the Hyperpro srings are so stiff they could hold a truck. but that will be in march when i go UK.

[jerryz]

OK update........ its all back to basics with the standard Ducati springs refitted and Showa 8 weight oi with 135mm airgap. After consulting my notes i decided to have have compression set at 4 clicks in ,rebound is set at 9 clicks and sag at 24mm already before even riding it is evident that the standard springs move as the bike settles on its suspension.then went for a 60 mile ride on my standard loop around Chonburi Rayong area, in bends the bike felt good , comfort was good the bike is now safe at high speed over bumpy roads as the springs actually work instead of locking up.
The handling is reasonably good as well ,pretty stable so the bike is now usable and safe...Its not perfect but for now until the forks come to UK in March It will do.

Oh yes i also moved the bars 10cm forward and 2cm higher by using different riser so a bit more weight on the front also helps stability and steering .
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MONSTERMAN

[koko64]

Great to hear that you found a safe compromise untill you find that ideal set up. And congratulations on your epic journey!

Cheers
Tony

[jerryz]

Sorted at last ......Met a German chap from YSS suspension at the Bangkok bike show, mentioned my fork problem and he said drop them in to YSS workshops,they design suspension systems for bikes and have a huge factory ,they opened up the cartridge and drilled some bigger holes in the shim stack according to a chart and data he has .He also checked my springs and said the standard Ducati ones are fine for my weight .The Progressive Hyperpro springs he said were completely wrong they are way too stiff even if I was 150kg. Not 80kg. we put 8w oil back in and hey presto the forks are really nice now went for a 150mile ride and the handling is noow superb as it should be , oh and the cost from YSS only $60.
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MONSTERMAN