Ducati Monster Forum

Has anybody toyed with the idea of converting the valve belts over to chains? I wish I had the capability of doing it but I lack the experience and the equipment to do so.

Discuss....

1st....think about the added weight the drivetrain will now have to push in terms of how much a chain weighs versus a belt...2nd...you need a hydraulic tensioner of some sort with a high impact plastic runner shoe for to keep a level of tension on the chain as it runs on it for to maintain a certain specific level of slack/tension added to the parts to bolt on...and keep in mind...chains have a lifespan also in terms of stretching....and you also have the issue of lubrication if they aren't bathed inside the engine along with everything else with the oil....

just my intial four and a half cents

I've been thinking about a gear drive.

The latest Ducati engine (1199) has gear drive doesn't it?  It would be something to consider if the aftermarket provided a good one, but no way I'd try it on my own.  It would be nice if you could go with gear drive and MBP collets for the valves and really extend your service intervals.  

The HD aftermarket offers a couple of kits for gear driven cams.  I have the S&S gear driven cams in mine.  Sometimes I wish the Ducati aftermarket was a lot larger.  It would be awesome to be able to buy larger capacity 2V engine when my current one craps out for around 5K.

the SuperQuadro is some kind of hybrid chain/gear combination.  The geared bit is to pass the cam drive over to the other side of the engine for some reason not apparent to me.

Travman - Are you saying you would buy a gear-drive cam kit if said thing actually existed?

The whole point obviously would be to get a nasty gear whine noise, add a supercharger drive, and have really long maintenance intervals?

(http://www.motorcycle.com/gallery/gallery.php/d/312535-2/SQ_CAD_crank_piston_cams3.jpg?g2_GALLERYSID=TMP_SESSION_ID_DI_NOISSES_PMT)

Because it's easier to only build one kind of cylinder/head combo instead of a front and rear cylinder/head combo.  By running the cam chain on opposite sides of the engine, they likely can use the same jugs and heads rotated 180* for both cylinders.

I would recon that they went ahead and mixed chain and gear drives to reduce the amount of chain and other mass rotating around.  Either you have two big sprockets up top, one big sprocket and gears, or a little sprocket and gears.  Why not go with smaller chains and smaller gears to get the job done?


OP:  I wouldn't imagine it being too hard to do if ya guy had some machine tools.  I see no reason why you would need a hydraulic tensioner...  a spring pushing a roller (or tiny sprocket) in the same location as the stock roller would work just fine.

Right.  I remember reading that now.  I just have a job that makes my brain dribble out of my ear.

Especially since the biggest loads the valve train chain/sprockets are going to see is engine acceleration, rather than having to pull/propel the entire bike.

There's more acceleration, but there's much less mass being accelerated.

The chain does not have to be huge.  Maybe like a bicycle chain but double width.  And with this I'm not looking for any performance upgrades.  It will just make it super reliable.  I would oil the chain every oil change and not have to worry about it skipping or breaking.  Plus the factory tensioner will just need a sprocket and a spring.

Drill a hole in the cover so you can shoot a bit of chain lube in it every 300 miles :P

No covers, and a scottoiler-type device!

Methinks my jeans wouldn't appreciate that...

This is crazy talk.

This is only crazy talk on the surface.  Kind of like the Aurora spy plane...  ;D

Given the time, inclination, and money, anything is possible.  We could solve PC's "greasy jeans" problem with chain guards.  We could solve it with a self-contained oil bath (you have to put an oil seal behind the cam gear).  Same thing with gear drive. 

The only crazy talk is the thought of "donating" the man-hours to the project...

That's what engineering students are for.

...or so I've been told.  [coffee]

THere are already oil seal behind the cam gears, they keep the oil in the heads.
I think sealing the cam covers and opening a bottom oil hole for it to drain into the case and having two holes above the cam sprockets would let the oil fall directly onto the chain.

maybe use the old 900 style of outside oil lines to avoid drilling into the case/heads.

I don't think the plastic chain covers would appreciate the hot engine oil.

replace them with aluminum ones.