Should I change the check valves after years of storage?

[Richyzfr1000]

Hi everyone, I just bought a 1973 Suzuki GT 380 and I am in the middle of servicing it, getting it ready for its first start in 30 years. I bought all of the typical replacement parts, points, plugs, carb kits, etc etc

My question is: Would it be a good idea to replace the check valves? Do these go bad from sitting? The oil injection tank is still full and oil hasn’t filled up the motor. Just being overly cautious before running it. Thanks

[akendall1966]

My experience from stripping a few T500 valves down is the 2 stroke oil after ball around the spring looses some of its more volatile components over time and congeals into rubbery crud that interferes with the ball and spring operation.

I would not jump straight to replace, but would suggest you give them a good soak and flush through and see if they are good or not and decide. Soak the check valves in carb cleaner for a few days to dissolve any crud, then flush through with carb cleaner from a syringe or squeeze bottle, you don't want anything with high pressure as the spring is awfully fine and could be damaged.

You could prime with oil, hang up and see if it leaks as a test. If you have bad leaks you will need to refurb of replace.

[GTandcbr]

First thing i would do is drain and clean the tank. You have no idea what is in there! Once empty clean the tank with simple green and make sure its dry. Then remove the pump. Replace all the little o rings which provide a seal so no air gets in. The old ones will be scrap. Flush out the tubes as described above. Prime the pipes with fresh oiland hang them up banjos downward overnight. If there is oil on the bench in the morning and air bubbles in the pipes then they are faulty.. Replace the gaskets that go either side of the banjos. Replace pipes to engine prime again,this will inject a little oil onto the bearings ready for the startup. Replace pump. Replace tank fill with oil bleed downpipe to remove air. Away you go! This may help https://youtu.be/necW4LnXBHM" onclick="window.open(this.href);return false; i know its a 550 but its the same pump. Good luck

[Richyzfr1000]

Great to know, thanks for the information. I will start inspecting the injection system tonight.