The Desaxe head gasket for correcting cylinder alignment is here

jseng1

jseng1

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When Norton went from 650 to 750 then moved the cylinders backward to accomodate the larger bore. But they did not realign the cylinder bore with the crankshaft center thus causing more vibration, more piston skirt wear and strain on the components. Instead of the cylinders being behind the crank centerline – they should be in front of it – ideally 1 or 2mm in front. This is called “Desaxe”. The JS wedge base gasket achieves this by moving the cylinder centerline approx 1 mm in front of the crank center giving you a more reliable and longer lasting motor with increased performance.

The image below shows how the wedge base gasket tapers in thickness from one end to the other (use yamabond sealer). To restore compression you should go to a thinner .003″ or .021″ JS head gasket. Its a drop in gasket. All the cylinder bolts and nuts screw in just fine.

top view
The Desaxe head gasket for correcting cylinder alignment is here


side view showing how the wedge shaped gasket tapers from one end to the other (.008" to .075")
The Desaxe head gasket for correcting cylinder alignment is here
 
Last edited:
jseng1 said:
When Norton went from 650 to 750 then moved the cylinders backward to accomodate the larger bore. But they did not realign the cylinder bore with the crankshaft center thus causing more vibration, more piston skirt wear and strain on the components. Instead of the cylinders being behind the crank centerline – they should be in front of it – ideally 1 or 2mm in front. This is called “Desaxe”. The JS wedge base gasket achieves this by moving the cylinder centerline approx 1 mm in front of the crank center giving you a more reliable and longer lasting motor with increased performance.

The image below shows how the wedge base gasket tapers in thickness from one end to the other (use yamabond sealer). To restore compression you should go to a thinner .003″ or .021″ JS head gasket. Its a drop in gasket. All the cylinder bolts and nuts screw in just fine.

top view


side view showing how the wedge shaped gasket tapers from one end to the other (.008" to .075")
Click to expand...
Base Gasket?
I like the idea, but your claim about less vibration - have you verified this or is it purely theoretical? i.e.:what improvement in vibration can be expected and should the crankshaft balance factor be altered to accommodate the better balance?
Cheers
 
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robs ss said:
Base Gasket?
I like the idea, but your claim about less vibration - have you verified this or is it purely theoretical? i.e.:what improvement in vibration can be expected and should the crankshaft balance factor be altered to accommodate the better balance?
Cheers
Click to expand...
I don't think this has anything to do with balance factor; it's more about the forces acting on the piston which position it differently through the power stroke which provides several advantages including less wear, less vibration and better geometry which gives a slight increase in power.
 
robs ss said:
Base Gasket?
I like the idea, but your claim about less vibration - have you verified this or is it purely theoretical? i.e.:what improvement in vibration can be expected and should the crankshaft balance factor be altered to accommodate the better balance?
Cheers
Click to expand...
See this article:

https://motocrossactionmag.com/ask-the-mxperts-what-is-a-desaxe-engine/

The next question is - should I offset the wrist pin as well? Maybe not a full millimeter but at least .5mm

Batrider - I don't see a problem - the angle is not that great and there is some loose play between the threads so the nut still comes down flat. Its no problem for the 850 through bolts either - the top end is only deflected about 1/32" because the bolt hole is oversize. The important thing is that the engine is happier.
 
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