Ducati ST2 forks on a 620 Monster

rohalloran · January 30, 2016, 03:02:39 PM

I have read ST2 adjustable forks are a direct swap for non-adjustable Monster forks. The only difference is the ST2 forks are 25mm shorter. Has anyone ever done / read about this conversion and is the 25mm difference in length an issue? I don't plan on clips so can't see it being to much of an issue.

Thanks in advance.

Rob

DarkMonster620 · January 30, 2016, 06:57:38 PM

just leave them flush with top triple

rohalloran · January 30, 2016, 07:17:07 PM

Ya I though that. Is 25mm a big drop though? I know it will affect the trail / rake and steering slightly.

I was also informed that if the fork is 25mm shorter with the same travel, you run the risk of the front tire kissing the valve cover. Ever hear of this happening?

ducatiz · January 30, 2016, 07:25:52 PM

you have a slightly higher line of sight

DarkMonster620 · January 30, 2016, 07:53:27 PM

Quote from: rohalloran on January 30, 2016, 07:17:07 PM
Ya I though that. Is 25mm a big drop though? I know it will affect the trail / rake and steering slightly.

I was also informed that if the fork is 25mm shorter with the same travel, you run the risk of the front tire kissing the valve cover. Ever hear of this happening?

you are compensating by leaving the forks flush with top triple . . . maybe not the full 25mm but at least 15

Howie · January 31, 2016, 12:11:45 AM

My 750 measured 17mm over the triple when set at the factory height, which would leave you 8mm short if you were level with the triple assuming the 620 and 750 forks are the same length. Only a little lower than stock. Not enough to stop me. Stock height is 205.5 from the top of the fork (not including cap) to the bottom of the lower triple.

stopintime · January 31, 2016, 04:38:39 AM

, but the ST4 fork is longer, right?

Howie · January 31, 2016, 05:01:03 AM

rohalloran says shorter

rohalloran · January 31, 2016, 05:57:53 AM

Hi all,

When I got my Monster the top of the forks were flush with the top clamp so I assumed thats the way it should have been. Looking at photo online, now I see that on most they, do sit about 17mm above the clamp as said by @howie. My forks are 725mm in length.

@howie, @stopintime these are the measurements and details of the forks I am looking at:

Ducati Monster S4 from year 2001 to 2002
ST2 with 944 engine from year 1997 to 2000
ST4 with 916 engine from year 1999 to 2003

Sizes
length 695 mm
diameter top plate 50 mm
diameter lower plate 54 mm
diameter stem 43 mm
distance between holes for calipers 65 mm

Ducati code left fork 34020701b
Ducati code right fork 34020691b

I noticed there is no Showa stamp on my current forks. Does that mean they are Marzocchi's? The Monster is a 2003 620ie

Thanks all.

ducpainter · January 31, 2016, 06:25:41 AM

620 did have Marzocchi forks.

The most important measurement besides the ones for the triple clamps, if you want to keep the geometry the same, is top of triple to center of axle.

rohalloran · January 31, 2016, 06:45:50 AM

Quote from: ducpainter on January 31, 2016, 06:25:41 AM
620 did have Marzocchi forks.

The most important measurement besides the ones for the triple clamps, if you want to keep the geometry the same, is top of triple to center of axle.

Thanks. I'll keep that in mind. Based on what I am readign I think the shorter forks maybe not cause too much issue now and its better that they are adjustable

ducpainter · January 31, 2016, 07:00:18 AM

Dropping the front, and or raising the rear, will change the handling. Many like the result. I do.

The Showa adjustables are a better fork, but they aren't as good out of the box as they can be made to be with some upgrades.

rohalloran · January 31, 2016, 07:18:54 AM

Quote from: ducpainter on January 31, 2016, 07:00:18 AM
Dropping the front, and or raising the rear, will change the handling. Many like the result. I do.

The Showa adjustables are a better fork, but they aren't as good out of the box as they can be made to be with some upgrades.

Any particular upgrades you woudl recommend? The bike will just be used for Sunday spins and about town on sunny summer days.

ducpainter · January 31, 2016, 07:51:17 AM

Quote from: rohalloran on January 31, 2016, 07:18:54 AM
Any particular upgrades you woudl recommend? The bike will just be used for Sunday spins and about town on sunny summer days.

Suspension upgrades give the biggest bang for the buck of all moto upgrades IME. Whether you're a go fast guy, or just a casual rider. There's nothing like riding over a road irregularity and not having it affect the bike at all.

You should at least make sure that the springs are correct for you. The ones in the forks are most likely not unless you're about 160lbs. That would be, IMO, the ones that give you about 30 mm of sag with the springs preloaded about 15mm. If you add excessive preload to get the sag you want the initial hit will be harsh. You'll also want to freshen the oil. That is roughly a $200 upgrade/service.

The smoothest ride will be with correct springs and an upgraded valve and shim stack for your road types. If you're in cali with relatively good roads you'll need a different stack that if you're in the northeast with our upgraded cart paths that turn into motcross courses every spring and go downhill from there. Look into Race-Tech. Their stock shim stack recommendations are for Cali roads. There are suspension tuners that can modify the stack to give you a really plush ride.

That will cost you more money...maybe more than you want to spend for a weekend putter.

rohalloran · January 31, 2016, 08:00:48 AM

Thanks @ducpainter. Lots to consider there. The upgrade might have to be part of stage 2 after the rebuild. The rebuild list is getting lander (and better) by the day...

Sounds like the ST adjustables are a good place to start through. My own forks are pitted and need new seals / dust covers so new forks look to be the way to go

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Ducati ST2 forks on a 620 Monster