696 heads on older monsters

[caperix]

Has anyone tried it?  With how much more power they made on a 695 engine, that uses the same heads as an 800, it would be interesting too see what kind of gains they would make on a larger engine.

[Raux]

if i read right, the 696 heads give one more cc because of the shape of the chamber. not sure if the chamber shape or the new siemens system is responsible for the power gain between the two.

[Duck-Stew]

Same bore, same stroke as the 695.  There is no difference in displacement, but because of the new cylinder barrels and heads, they needed to distinquish the 695 from the 696 so they named the new 695 motor the 696.  Because the bore and stroke determine the displacement, the combustion chamber shape wouldn't have an effect on displacement.  A larger combustion chamber would just have an effect on compression.

(disclaimer as I haven't had a 696 torn apart and I haven't looked at the parts diagrams either)

696 heads resemble the DS1000 heads so I believe they would use a cylinder head gasket between the barrel and head (like a DS1000 motor does) and the 695 motor does not.  Soooo.... in order to use the heads, you would have to use the barrels as well and I don't know if the newer barrels fit the older cases or not.  Some day, I'll get a 696 motor to F with and will have answers then, but till then...

The power difference?  Simple: air-flow.  More air in and out of a motor, the more power.  Simple as that.  The 696 heads flow a LOT more air then the old 695 heads to (and the 695 heads are pretty damned good).

[kopfjäger]

More power than the 800?

[Howie]

Other issues would be whether or no oil passages line up and squish/valve interference.

[krista]

The DS engines (1000, 1100, and now the 696) have straight intake ports, which is a vast improvement over the legacy 2V heads as found on 600, 620, 750, 800, and 900 models. The 1000DS was the first 2V heads that actually respond to normal "porting", while the legacy heads required mad scientist level of porting to get results (like from Bruce Meyers, Guy Martin, etc). I have dreams of what could be gotten from putting 696 heads on legacy engines, however I have no news or research of such a mating. As Stew said, there's the oil passages and gasket to confirm. And there's the stud spacing, too...

Chris

[Raux]

DS? the 696 is a Dual Spark engine?

[krista]

No, but the heads are similar to 1000DS... look closely...

[Raux]

ok so that leads to the question... what size valves can be used and what kind of port work can be done on the 696?

[krista]

All that is answered by taking the heads off, changing parts, reinstalling, and testing. 

[caperix]

So who's going to donate their 696 for science?
The valves are allredy pretty big on them, 1mm larger intake & .5mm larger exhaust the the 800/900.
I took a look at the parts catalog, they do use a gasket between the barrel & the head like the DS motors.  The base gasket is the same part number as a 1000 DS so they prob. use the larger stud spacing of that engine.

[kopfjäger]

Paging Brad Black......

[Raux]

So who's going to donate their 696 for science?

uh depends on what the insurance company says.. long story another thread coming.

[krista]

Hi Raux, sorry to hear about that. As a shop owner, I have helped people with insurance situations before; you're welcome to call us to see if we can help you with your situation.

Chris