'01 Mazocchi forks - rebuildable?

[sp838]

After doing the front end job on my '01, the old stock Marzocchis were just laying around, so I decided to put them on a CB450 project bike. I'm wondering if these forks can be re-valved and sprung. This Honda will end up being quite a bit lighter than the V11, I'm thinking it might end up being necessary... What is the voodoo with these guys?

[docc]

Springs are easy, but the forks probably should be mounted to the bike to get preliminary sag measurements to determine the best spring for your weight and style. Oil selection goes a long way toward tuning the damping, but is no substitute for altering the high speed damping internally.

 

AFAIK, GuzziMoto is the only member who has ventured into altering the porting inside the Marzocchis.  In fact, I'd like to invite him to re-post his method here since much of that was lost to the hyperbole of Another Time . . .

 

41mm 'zocchs oughta look pretty beefy on a CB!

[sp838]

It's gonna look pretty tough (sorry so low res, and also somewhat off topic):

 

[docc]

Are those V11 triple clamps?

[sp838]

yes, with some grinding and polishing to remove the casting flashings. the top clamp has holes for handlebar risers, I think it is from a daytona or a sport 1100, can't remember.

[Craig]

AFAIK, GuzziMoto is the only member who has ventured into altering the porting inside the Marzocchis.  In fact, I'd like to invite him to re-post his method here since much of that was lost to the hyperbole of Another Time . . .

 

That's why I can't find that post...

[docc]

 

AFAIK, GuzziMoto is the only member who has ventured into altering the porting inside the Marzocchis.  In fact, I'd like to invite him to re-post his method here since much of that was lost to the hyperbole of Another Time . . .

 

That's why I can't find that post...

 

These are MUCH better times here!   A credit to our current community!

[Scud]

It's gonna look pretty tough (sorry so low res, and also somewhat off topic):

 

image.jpg

 

Looks like a fun project.

 

At least there's a hammer in the picture. That makes it OK. 

[docc]

 

It's gonna look pretty tough (sorry so low res, and also somewhat off topic):

 

image.jpg

 

Looks like a fun project.

 

At least there's a hammer in the picture. That makes it OK. 

 

hahaa! I missed that! A true mark of mechanical devotion!

[danl]

That front end is going to look really trick!  Not sure I've ever seen an inverted fork with a drum brake.  Suzuki 4LS?  Keep us posted...with pics!

 

edit:  Sorry for that diversion from the original post...I don't have any experience modding the Marzocchi forks, but I know a few people here have done mods or sent them out to have work done (maybe to Todd at Guzzitech?).

[Gottagetone]

That is going to be pretty sweet!

[GuzziMoto]

My experience was specific to the early Marzocchi's, as the wifes V11 is a red framer.

If your top triple has the hole machined in it from the factory for a handlebar riser it is not from a Daytona, nor from a sport 1100. They had clip-ons. There were a few V11's that had handlebars stock. As far as I  know even the ones that did not have handlebars had the boss cast into them for where the hole would go. That is the way the wifes V11 was, no hole for the bar risers but the boss was there. I just drilled holes in the clamps and mounted bars.

As to the dampening, this is what I found from memory.

There was zero compression dampening until the forks were about 80% through the available travel. Then there was a massive amount of dampening. This was basically hydraulic bump stops. Turning the compression adjuster had no effect on the first 80% of travel, and little effect on the last 20%. The reason this was that way was two holes in the damper cartridge that allowed all the oil to bypass the stack in the piston until the piston went past the holes. The holes were at around 80% of travel. I found this during service of the forks. I took the springs out and put them back together. I then could feel the dampening and how it changed through the stroke. I noticed the compression dampening was nothing until it hit the last 20% then it seemed to lock. I took them back apart and found the two bypass holes. I blocked one of them off and found a weight oil that delivered what I thought was the right amount of compression dampening. I don't remember what that was. I seem to recall the rebound was stupid but not as bad as compression (each leg does one or the other).

The thing I fall back on is this is just suspension. It is not special because it is a Guzzi. There is compression dampening, rebound dampening, and springs. They all have to play nice together. Only the details on this are different because they are Italian forks. The way they are built is a little weird, having compression in one leg and rebound in the other. But I had a Buell that was the same way and now other major brands are going with that set up as well.

[docc]

Thanks for reposting that. I couldn't remember if you added a new hole or changed hole sizes - I completely forgot that you blocked a hole off!

[GuzziMoto]

Yeah, with both holes it flowed so much oil that none of it was forced to go through the shim stack. Some suggested thicker oil but I think it would have to be really thick and that would mean you had to change the shim stack to work with the thicker oil.

I think my solution was blocking off a hole and slightly thinner oil to get compression dampening through the whole stroke. And now the adjuster actually has an effect. Before it did not, you might convince yourself it did, but with the springs out you could really see that the adjuster had no effect until the piston went past the holes.

[sp838]

Thanks for this info. I wonder if this is something Stig Peterson could improve on, or if his expertise only applies to Ohlins stuff...