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Wadester 04-28-2012 08:49 PM

Recipe for dirt monster
Some years ago, I spotted the Terra Mostro - a Ducati 695 converted to a dual sport machine:

I had always wanted a Ducati - and this was definitely my style. Sadly, I don't have the kind of money they wanted - and apparently they have also stopped the conversions (they didn't answer email asking if they would sell parts, and website is gone now).

Oh well, it's not rocket surgery after all.

So! First ingredient for Dirt Monster is:

A Monster!

I've been collecting information on the Terra Mostro and other successful Ducati conversions, and I'll be posting the measurements and choices as I go along.

sailah 04-28-2012 09:02 PM

Nice, that's my next conversion. I figure you could easily make a better bike than the Terra Mostro for way less.

I want to use the m900...

Wadester 04-29-2012 02:29 PM

Topic of the day: The front end.

Ducati head bearings are 35mm ID x 55mm OD x 14mm ht. This is absolutely true for my Monster, and from what I can tell this is the standard for most Ducatis.

For example, the Fork of choice for many conversions is from a Honda XR650R - a Kayaba 46mm non-USD.
Bearings are 26x47x15 top and 30x51x15 bottom.

Dirt bike bearing sizes are all over the place, but they're all smaller than the stock Ducati. Some adaptation will have to be done. Either a shim sleeve on the XR stem for the lower bearing, or a new steering stem. Looks like there's enough room for either way, but a sleeve will be easier:

The top is a different issue, but a 2 pc sleeve/collet would be a possibility.

The Terra Mostro did something a bit different - check out that top spacer:

That may be more about ride height and head angle than anything, but I'm not ready to figure that out yet.

sailah 04-29-2012 03:29 PM

Why don't you just use USD forks from a CRF450? They have a 30mm stem and the 30-55 bearing is available off the shelf.

I suspect that the reason they needed that large steering head extension is that typically the headstock length on dirt bikes is much longer than a sport bike. In order for the triples to grip the fork tubes in the right spot (on USD forks) you have to lengthen the headstock. I did on my CBR conversion, the Fz1 was minimal.

If you go non-USD forks that isn't the case asyou can probably grip the forks wherever you want. but the stresses from using the bike might be an issue. If you have access to a lathe, it fairly simple to make that extension, weld it on, and then brace it back to the frame. That's what I did at least.

huzar 04-30-2012 12:01 PM

I was wondering when you were going to get around to building the Monster.


Wadester 04-30-2012 12:53 PM


Originally Posted by huzar (Post 18579104)
I was wondering when you were going to get around to building the Monster.


It's so much fun to ride, I'm gonna have a hard time taking it apart! Meantime, making plans and buying parts. I currently have put almost as many miles on it as the PO did in his 2 years ownership.

sunset_ryder 04-30-2012 03:16 PM

:lurkYou got my attention. Sally forth!

Wadester 04-30-2012 03:41 PM


Originally Posted by sunset_ryder (Post 18580510)
:lurkYou got my attention. Sally forth!

Who you callin' Sally?

Gummee! 04-30-2012 06:08 PM


Originally Posted by Wadester (Post 18580705)
Who you callin' Sally?

Well, he ain't talkin to me.

Get on with it already! (so I know what to do too! :augie)


Wadester 04-30-2012 07:19 PM

I knew I shoulda waited til I was done - but it's too late for that. Repeat after me: patience is a virtue. Patience is a virtue......

Anyways, here's a little triple tree separation comparison - Monster vs XR650R:

My! What long legs you gonna have!

Triple tree offset is not that much different:

So the additional offset of the XR front axle vs the centered Ducati axle will be mostly what I will be dealing with. And the change from 120/60 17 to 90/90 21 will more than make up for that loss of trail. Maybe I won't have to "pitch" the chassis to slack the head angle after all.

But I got one of these anyways:

Height adjusting strut to replace the fixed one - will need a longer center section to match the longer rear shock.

Wadester 04-30-2012 07:36 PM

Getting back - there is a bit of difference between the 160/60-17 and my DR's rear wheel at 130/80-18:

Lot's of room on the sides, but maybe the inner fender needs a little something:

Lot's of clearance at the front - not.

That was with the adjuster almost to the front, but still. A swingarm stretch is needed for clearance, even if I didn't want to balance the front extension.

donmoto 05-01-2012 08:06 AM

subscribed! I figured monsters shouldn't be too difficult a conversion. The only things I've really wondered about are dealing with the low sitting exhaust and if there are already larger tanks available for them.

Wadester 05-01-2012 11:11 AM


Originally Posted by donmoto (Post 18585233)
subscribed! I figured monsters shouldn't be too difficult a conversion. The only things I've really wondered about are dealing with the low sitting exhaust and if there are already larger tanks available for them.

The only larger gas tank I'm aware of is the California Cycleworks MTT43, at 4.3 gallons (vs stock at 3.6 gallons) and $537:

It does come in natural, so you can see how much fuel you've got left:

hitmanlol 05-03-2012 03:36 PM

You might be in luck.... I saw a posting on ebay a long time ago for a guy selling parts to do this conversion. Here's a snippet from his ad:

Disclaimer: this is not a “Terra Mostro” kit, and while I’ve spoken with the owners for advice and suggestions, they supplied none of this (nor are they currently doing so for the public).

While most of the parts below are Ducat parts that should simply bolt on, this is not a turn-key project and will require some custom fabrication.

The fork tube on a stock Monster frame will need to be extended 1.5” to accommodate the longer Multistrada steering stem.

Front axle spacers may need to be cut to accommodate the wider Sport Classic hub.

New mounting points for the long rear shock will need to be fabricated.

If you choose to replace the stock tank and seat with the optional KTM items (below), you’ll need to relocate the battery, fuse, block and seat mounts.

Multistrada front Forks and Triple Clamps ($400)
Multistrada front brake lines ($50)
Multistrada clutch line ($30)
Multistrada Right and Left Peg Mounts and foot levers and linkage ($225)
Multistrada swing arm axle (runs through peg mounts) ($27)
Ducati Sport Classic Hubs ($400)
Excel Rims (19” x 2.15” Front ; 17” x 4.25”) Rear ($382)
Excel front Spoke kit ($65)
Continental TKC 80 dual sport tires (19/110 Front ; 17/150 Rear) ($280)
Ohlins KTM rear shock, long travel but may need heavier Oil or Spring ($167)
Total = $ 2026

Also available as separate purchases, but not included in this auction:

Acerbis 6.6 Gal Enduro Tank ($229)
KTM Supermoto Fender (white/and black) ($40)
KTM low gel seat ($99)
Total = $368

hope this helps, great build!

MODNROD 05-03-2012 04:24 PM

Lots of info here.......

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