KR-1S.co.uk Forum

Hi there,

Sorry to ask such a simple question but my 1991 KR1-S is my first bike and i am a little clueless with some of the regular maintenance.

I want to drain virtually a full tank of old 2 stroke engine oil from the oil tank and replace it with some new fully synthetic stuff. I understand that getting air in the pipe is bad, but don't have a clue how to bleed the pipes and pump so i was wondering if there was any way that i could do this without the "need to bleed".
The guy in the shop mentioned something about capping the pipe that connects to the bottom of the oil tank to stop air getting in, then draining the old oil and replacing with the new stuff to then connect the pipe back onto the tank but this seems a little odd as even being very careful you will still get a small bubble of air trapped!

Does anybody here know the best way to replace a full tank of very old engine oil without having to bleed anything OR could explain the procedure of bleeding air from the oil pipe and pump?

Great forum by the way, i have subbed


Daz

I'd drain the oil from the tank by taking the oil suppy hose from the oil pump and drain everything in a container. Then I'd put the hose back on and refill the tank with fresh oil. I'd then start the engine (tick over) and manually (just pull the pump lever) set the pump to deliver it's max. output. You'll then soon see there's fresh oil in the oil feed pipes.

Charles

Thanks Charles i'll try that this afternoon.

It's also best to run some premixed fuel in the petrol tank (use some of the old oil youve taken out) while your doing this untill the air bubbles have passed through. Yes, it'll be hellishly smokey, but it'll make sure youve got plenty of lubrication to prevent engine damage.

Followed Charles and Scotts suggestions, crimped the pipe with some rounded locking pliers, emptied the old oil out saving some to be mixed in with the fuel while the air is pushed through and fully cleaned the oil tank inside and out with petrol and then washing up liquid and warm water, filled tank with new fully synthetic oil, took off the oil pump black shroud, started the bike and left idling while i set the pump to maximum flow by moving the cable guide clockwise all the way and after around 5minutes the air bubble could be seen moving rapidly through the carb feed pipes. Left it idling for around 10minutes keeping an eye on the feed pipes to make sure that no more air was present. Drained the fuel tank of the oil/petrol mix and refilled.

Job done thx guys.

Glad you got it all sorted with some nice fresh fluids now.
So, has the smoke screen cleared yet?