Here's a link to what I wrote up on the respringing my 620:
http://www.ducatimonster.org/forums/accessories-mods/178703-500-suspension-upgrades-620-a.htmlHere's the gist:
$500 suspension upgrade?
The stock forks are way undersprung even for someone your weight. According to Marzocchi, the forks have a progressive .45 spring. I've compared my stock springs to the replacement .9 traxxions I'm using and its a significant difference. get new springs.
The shock spring should be ok on that budget once preload is correct. I bought an adjustable dogbone and raised the rear about 20mm, which put more weight on the front and -- to me -- changed the handling for the better. I'm also respringing my forks and adding a penske sport shock (about 550). So here's what I would recommend in order:
-respring your forks with the proper springs (traxxion or ractech are fine). Do the work yourself and use the stock oil at the stock height for now. Ride for a while and adjust weight and hight to fix any problems you note. I say don't bother with buying used forks and rebuilding at this budget point. springs and oil will be valuable enough and you need money for a shock.
-set your sag properly on front and the back! Nothing else is worth doing until you have this done. do it yourself. its free.
-get an adjustable dogbone and play around with ride height to see what you like.
-Save up enough money to replace the rear shock with a penske sport shock. Best value for the money that I've found and it can be owner upgraded from emulsion to have a remote res later on if you feel the need.
I've tried used shocks and such and don't think they are worth the money unless you can get a great deal on a used rebuildable shock like a penske, but then you have to rebuild it anyway... I'd go with a new sport and upgrade in a few years when its time to rebuild anyway.
You need a proper front end headstock stand, not just the regular stand that holds the forks. I picked up the Handy headstock stand and highly recommend it. Pretty cheap too -- around 150 with s/h I think. Other than that, you need the regular tools, metric hex set, wrenches, etc. If you don't have it already, buy the DT mantenance manual:
http://www.desmotimes.com/ click on the left side under written & promo. Worth 3 times what he charges. It will walk you through everything. But BE CAREFUL, the rebuild information on the forks is not correct as it shows the wrong order for the bushings and washers. Take your forks apart one at a time and keep one as a model just to help you rebuild the other.
A good vice will make this project much easier since its nice to have a third hand for some parts. I picked up the aluminum Traxxion vice covers for a few bucks to make sure I didn't mar the forks at all. Work like a charm. But the job could be done w/o the vice too with a little ingenuity (Loosen the cap and bottom bolt before you take the forks out of the triples)
The whole job is very doable by a newbie if you have even a minimal level of mechanical skills. You do NOT need a spring compressor or anything fancy to put the springs in or take them out. Follow the DT manual and you'll be in good shape. Only tweak I can make is that you want to confirm the direction your new fork oil seals go into the forks since some brands go spring up, some spring down. They fit either way, so check when you buy them. And never reuse the stock oil seals.
The traxxion springs are of a length that allows you to reuse the stock spacer, but I haven't put the forks back on (getting new tires put on right now and it was 11 degrees today) to recheck sag yet.
Pump the hell out of the cartridge until you hear nothing but air and (sounds like a bike pump) to clear it of all old oil. clean the hell out of every part of the forks with lots of brake cleaner when you take them apart. You'll be shocked how shitty they look. Each fork is supposed to have about 15oz of oil in it. I pulled less than 9 out of one and probably less than 6 out of the other one. All the oil was sludgy and smelled like bad calamari. That alone could explain the crazy harshness even w/o factoring in the low spring weight. I'm expecting great things out of these rebuilt forks. Not ohlins by any means, but plenty good enough for non-track riding. And it will have cost me less than $300 including the wheel stand I can use on just about any bike in the future.
By the way, Mike Hardy at Traxxion spent a bunch of time working with me to find the right springs, seals, etc. for this bike. If you call, mention I passed his name along. It won't benefit you or me, but it will let him know that his good customer service paid off.
He has it on file now, but the springs you need are 38x273 x whatever rate you want. Seal is FSO43 x 54 x 9.5. If you have a buffer in your forks (black plastic deal on the main cartridge shaft), the springs will only go on one way since one end of the spring has a smaller internal diameter than the other. Some folks have trimmed the buffer with other springs, its not necessary with the right ones from traxxion. Just flip them over and slide them on (after the spacer).
Forgot to mention. do one fork at a time all the way through reassembly so you have one fork to use as an example in case you forget how it goes back together. this is the bottom to top order from my forks:
dust seal, lock ring, oil seal, washer, sliding bushing and the captured bushing. some sources show the washer going on last (top), that does not work on the Marz forks I have.
I was finally able to take a shakedown ride on the bike with both the $120 DIY rebuilt forks and the $600 Penske sport shock. After 100 miles, I can tell you this is the best money that can be spent on this bike after going to a 14t front sprocket. I used traxxion 7 wt oil and the stock 100mm oil gap, stock fork spacer and stock length for the penske shock. Rough preload measurements show its all but dead on at 25-30mm front and back. I also have on new conti sport attack tires (awesome, btw) and a new Braking brand wave rotor with CM66 race pads. Here's some thoughts after 100miles in 40deg weather:
-All the road imperfections that used to hit me hard enough to pop me off the seat are now not a problem. I can feel them of course, but the bike does not react harshly and erratically like it did before.
-Road feel is amazing. I can feel
every road imperfection, which is annoying at first, but within a few miles you tune out what you dont' care about and all I noticed was that I could feel the road like never before which made my riding much more educated.
-Bike is substantially more planted. I never felt disconnected from the road like I did with the stock setup. In fact, I found that I was able to really relax my grip on the bars much more than before, which gave me much better control. I didn't feel like the bike was trying to shake the bars out of my hands anymore.
-For once, the bike tracks correctly. I was never able to ride the stock setup hands off without leaning to one side to keep a straight line. Runs dead straight now. I'll bet this is the result of a properly
-compression with the stock 7wt oil and air gap is about as high as I would want it for anything but track use. Unless you have really, crappy roads or want a really plush ride w/o much road feel, I think 7wt is the way to go with this setup. I might try 5wt sometime just to see the difference, but I think this feels perfect for right commuting and sport riding.
-Brake dive is almost imperceptible - at least compared to stock. Its amazing how much more control and feel you get with a proper spring and clean forks. I would routinely have 2-3 inches of brake dive in even a mild slowdown. Not anymore.
-squat under power is gone. I could crank on the throttle and feel the back end drop significantly as weight shifted to the rear under power. that is gone.
-but just like getting better road feel, I now get a much better feel for weight shifts on the bike on and off the throttle/brakes. control and feeling is perfect for me.
-The traxxion springs are linear in rate -- I think they are a huge improvement over the dual rate stock springs.
So IMHO., if you can up your budget from 500 to 750 or so, you will transform your bike with this setup. It will give you a much better tool for riding well. for what this did to my bike, I would have been happy to buy it off the rack for $1,500. the fact that it cost 1/2 that and a couple weekends of work is amazing. when the penske is ready for a rebuild, I'll upgrade it to the full blown 3-way adjustable just for grins. Until then, I'll be trying my best to find the edges of these sport attacks...
