I have a few ideas but at the moment, I'm thinking of a bypass that goes from the heater valve take off point on the head, back to the pump. This will require a different type of heater shut off valve, a T piece and a restrictor. I'm surprised no one has got to the bottom of this bypass removal before.
Pete
i've been looking into the same sort of thing as well, but it's a bit of a challenge to find a bypass valve that might be useful. there seems to be plenty of 4 way bypass valves available and some of them cable operated, but not a great deal of choice if you only want a 3 way bypass
about the only thing that comes close is this one - might be possible to rig it up to work off a cable...
https://www.ebay.com...7-/281115826873
routing back to the bottom hose have been done for years.
adding a restrictor has been done for years.
taking it off the head to the top hose in the "preferred" version.
the reason for doing this has nothing to do with removing the bypass but to help maintain temps around cylinders 4 and 3.