Cam cover breathers

'98 FL1 1.8 K motor-
Doing prep' in readiness for reassembly this weekend. I cleaned the cam cover ventilation mesh blocks with white spirit and noticed that the holes where the hoses connect are interesting sizes. On appears to be about 6mm which seem good to me, but the other would be a skinny 1mm.

Should I 'ream' out that smaller hole to improve cam cover / crank case ventilation or would this upset things?

It depends on which breather you are talking about. If the small hole is engine side of the throttle butterfly, then no don't enlarge it. If you do, you will effectively bypass the throttle butterfly causing the engine to race uncontrolled.

Nodge68 said:

It depends on which breather you are talking about. If the small hole is engine side of the throttle butterfly, then no don't enlarge it. If you do, you will effectively bypass the throttle butterfly causing the engine to race uncontrolled.

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Thank you, You're correct it does go to the engine side. Glad I waited for an answer - that could have been embarrassing.

htr said:

Thank you, You're correct it does go to the engine side. Glad I waited for an answer - that could have been embarrassing.

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The crankcase is vented by a constant vacuum applied by a small drilling from the inlet manifold.
At full throttle conditions this vacuum would reduce to nothing. The crankcase would then be vented by pressure, the gasses passing into the inlet via the large vent pipe.
It's all very carefully calculated so it's best not play with the setup.