450 Mark 3 Fork Springs

[machten]

Hi All,

When I using my 450 in Europe I found myself bottoming out my front forks from time to time. These are the 35mm Marzocchi forks on a late (1974) 450 Mark 3. I saw a new set of original springs available quite cheaply that might be a useful thing to have on hand when I take them apart but I dont have specs for them in any widecase parts manual I have. I'm not really sure that the springs are likely to be the main issue to be honest, but for $30 it might be useful to have them to hand just in case.

Does anyone know the standard length of them?

Has anyone used alternative aftermarket solutions that may be better?

Thanks,

Kev

[JimF]

Hi Kev,

This probably won't help you much, but until and unless somebody comes up with a better answer...

I switched a 450's 31.5mm forks to larger Paoli forks so I could but a Grimeca 4LS shoe on the front.

The fork tubes were too tall so I had them cut down professionally by Forking by Franks.

Then I could not get the original springs in the shortened tubes.

I found this company and called them:

http://www.cannonracecraft.com/

I gave them the dimensions of the springs I had and the length I had taken off the tubes.

The fellow on the phone asked some thoughtful questions:

How much did the bike weigh?

How much did I weigh?

What kind of riding would I be doing?

How stiff would I like the suspension?

They made me a new set of springs that fit the bike and my style of riding and felt great.

You might be able to pull out your springs, measure them, call a custom shop, and tell them all the vital information and that your current springs are bottoming out occasionally and have new springs made.

If you buy that spare springs you might send one of your current springs to a custom spring maker and maybe they can measure some attribute of the compression and using that make you springs that are somewhat stiffer. In the meantime you can use the new set until the custom set arrives.

Lastly,

Are you pretty sure you have enough fluid in the forks? (sorry, I have to ask... it's the kind of thing I would do, that is to say run the forks with no or low fluid.)

I am not a good fork person, but can you put a higher weight in and fix the problem?

[machten]

Thanks Jim. I can hear the oil in there under movement and it sounds right, but it could be low. They dampening seems to be acting OK under the bounceback test. I could drain them and refill to be sure, but having seen inside a few forks, I'll just do it properly and strip them as they end up full of dirty crap anyway that impacts on the dampening.

I've certainly used heavier weight oil in others and it has made a difference at the cost of losing some easy cushioning travel.

There's a good spring place locally, but I suspect it would pretty expensive. I've rebuilt Marzoc forks on my twins (38mm) and there's a dollar worth of 20 cent coins supplying some preload in each of the stanchions that has done the job for many years on one of them. If had to do the same thing on the 35mm, I think I'd have to use $1 coins. This could get expensive! I've never had these forks apart, so I'm not sure what condition they are in. On my bevel 900 I also had to make up some new nylon slider seals and that helped too.

Here's hoping for the $10 solution!

Kev

[Ventodue]

Stuffing the part number (0684.37.420) into Google and I get a site that claims :

28 x 430.

Make any sense, Kev?
------------------------
The original source site* references back to a Ducati official site**; so ...

* http://www.mc-lifestyle.com/1069119/068 ... ati-parts/
** http://www.ducati.com/services/maintenance/index.do

[machten]

Hi Craig,

Thanks for that. The ones I was looking at at longer, so I guess they may be Scrambler springs. I think I'll just start stripping the forks and see what I find.

Kev