Oil pressure test for 850 Commando

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Mar 1, 2007
Hello again. I have another stupid question. I will be firing up my newly restored 850 Commando Engine in a few weeks but before I do is there any way to test the oil pressure to the crank rod journals to make sure everything is working properly and in order before actually starting the engine???? . The engine had only 2000 miles on it when it was put away 17 years ago. I have torn it down all the way to splitting the crankcase and crankshaft in half. The sump was clean as a whistle and and it looked great. I replaced all seals and rod cap bearings as well as new rings etc. etc. Before I fire it up is there any way to be sure that there is oil getting to the rod journals??? I put on new seals to the crank end to timing cover and oil pump seals making sure the springs were in the proper directions to get a good seal. I also of course put on a new pump to outer cover seal. Any pre run test ideas???? This may sound silly but being a bit anal is better than a bloooown engine after all this work??? Thanks again guys and gals---Mark C.
I don't think there is any easy way of testing oil pressure on a non-running engine. Prior to commissioning any restoration or recommissioning a bike that has been dormant for some time. I generally fill the crankshaft with a hand operated oiling-can prior to putting the timing case on. I also remove the rocker-covers and liberally squirt oil on the rockers and shafts and down the push rod tunnels. I then push the bike around in gear with the plugs out for a bit. If you start the bike and immediately slacken one of the rocker oiler banjo bolts at the head, a spurt of oil will tell you that you have oil feed on the supply side. A look inside the oil tank at the return tube will confirm that the scavenge side of the pump is working.
Agree, always make sure the crank is filled with oil or its asking for trouble. For me the worst part is these agonising moments before you see the oil return to the tank, seems like hours sometimes and you start to imagine mechanical carnage. Starting a newly rebuilt commando is more stressful than childbirth!! :D
Hi Gino, Regards from an expatriate Scot stranded out in the East (thank God!). A liberal dousing with oil at critical points will in my opinion give enough safety to run the bike for a brief time to ascertain that there is indeed pressure present. A recent experience helping a friend with his 850 reinforces the fact that the oil pump has two separate functions (feed and scavenge) that don't always work in tandem. my chum had enthusiastically used silicone gasket when reassembling the crankcases after fitting a new cam and had blocked the oil return hole. There was good pressure at the rockers but no return to the tank. I was able to get sufficient debris out of the return drilling with a piece of wire and back flushing with my trusty oil can, to restore the scavenge function. The correct way to do things off course would have been to remove and strip the engine to clean everything out and then reasemble with the correct sealant, but he had ridden the bike to meet me and I ended up doing the job in the street. He has owned the bike for over 30 years and his chosen name is 'Norton Wong'. I hope to persuade him to change it to 'Harley Wong'.
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