Hi All

Is it normal when you remove the oil filler cap for the rev’s to increase on a 1275s motor?

How do you tell whether you have a vented or non vented cap

Thanks

Q1
Yes, the extra air into the manifold increases rpm.
Q2
The vented cap has an air intake below the handgrip.
Either cap type works. I have run one of each on my 1360 and 1412 stroker.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

An image of both types here - https://minisport.com.au/search/?q=oil+ ... cap+vented

The vented one is specified for closed circuit breathing, such as PCV.

_________________
ex-NSW Police 1970 MK II Cooper S
VMCI #43

Thanks all