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Old March 17th 2021, 05:10
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Join Date: Apr 2009
Location: Groningen The Netherlands
Posts: 104
Some photos of the 1971cc Type-4 build.

I started with removing the old oil galley plugs and tapping them for NPT plugs.

A NOS cranckshaft that I had ballanced with a 200mm. flywheel

cc'ed the CU-heads

Set deck height on new Mahle flat top piston and cylinder set

Because I used 1700cc rockers in combination with 8mm. swivel ball valve adjustment screws (I will come back to this later),
I had to make new longer pushrods for the correct rocker geometry.
To make it easier to turn the camshaft/crank I used lighter pressure springs.

And made my own adjustable pushrod

After testing and installing the correct jets in the DRLA carburators

I was the proud owner/builder of a smooth running type-4

The reason that I replaced the 1971cc type-4 with the 1904cc type-1 is it

left a smoke screen worthy of a bond car after only running for 100 kilometers.

The cause of the failure was a locknut that came loose of one of the swivel ball valve adjustment screws,

I am afraid to use these again. I am 100% sure I tightend all the locknuts.

With the locknuts loose the adjustment screws are very loose inside the rockers and can move side to side.

Is there enybody else who had this happen??

The nut became stuck between a rocker and the cylinderhead, breaking a piece out of the bottom of the head.

Resulting in a massive oil leak on to the exhaust

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