40 years of neglect...

[Cliff]

I don't know if this topic has come up before, but how often should the injector oil tank be taken off and serviced/cleaned on our bikes? I just sort of took the tank for granted and never thought much of it. Every 1000 miles or so throw another liter of oil in it and good to go, right? What could go wrong? Well, last year I had some issues with air bubbles in the oil lines. Removed the banjo bolt, back flushed the line with aerosol brake clean and was good for another 500 miles, then had to do it again and again. Sometimes I got 100 miles, sometimes 500! Not always on the same line and I was 1500 miles from home! I changed the lines when I got home with a set that I checked and know that the check valves are good. Problem solved. 2000 more miles riding and only a couple of little bubbles. This spring I start the bike and 200 miles later and I have air bubbles again. I change the oil lines, O rings AND pump. 100 miles later I have air bubbles again! My Son says to me "Dad, what about the oil tank? It hasn't been cleaned out in 40 years. Maybe there's some dirt in it?" This time I take EVERYTHING off. The tank, pump and lines. Clean everything, replace the O rings under the pump and washers on all the banjo bolts, flush out/clean the oil tank with varsol/compressed air, put her all back together and see what happens. 2000 miles later and not a single air bubble!! I can only assume that over the past 40 years, somewhere near 160,000 miles later and God knows how many liters of injector oil, that there has been some dirt/crud built up in the bottom of the oil tank and that's why the check valves were getting stuck open!!
Now, back to my original question. How often should the injector oil tank be serviced/cleaned?

[pearljam724]

I don't think there is a projected time line, Cliff. Just something everyone should address every few years or so. Especially, those that maybe purchased one of these bikes used. Good chance, on those bikes that it has never been done. In your case, you put all the miles on yours. Without a doubt, dirt can enter an oil injected tank. But, at the same time. Someone would have to be a little careless to introduce dirt into the tank over a period of time or dirt accumulating through dust, etc. Take into consideration that these tanks are suppose to have lids on them at all times. With the exception of filling them. Dirt on hands, dirt on quarts of oil, rags, not keeping the top of the tank clean, placing the lid in a dirty or dusty area, etc. to be introduced into the tank would be from neglect or from a very long period neglecting to flush it. All it would take is one correct sized debris to cause a problem. Not saying you neglected to keep dirt from entering. I'm saying, a lot of crap happens over 40 years.

[Fritz500]

On my 73 Titan I took the oil tank off and cleaned it out as I suspected there were issues with restricted oil flow.

What I found was the filter in the oil tank outlet was damaged (top broken off) and the bottom layer of oil had turned to a gel like substance and was about 20mm deep across the tank bottom.

I have ordered a new filter and thoroughly cleaned out the tank. I inspected another tank I had but no such issues were found. Both tanks were about the same age and mileage.

I'd say it pays to assume the worst. Removing the bottom fitting and inspecting the filter is a 5 minute job.

I replaced all the oil seals and believe that has gotten rid of bubbles in the oil lines. The seal on the bottom of the oil pump was a sloppy fit on the shaft and was possibly sucking in air from the crankcase.


Cheers

Geoff

[Suzsmokeyallan]

I also found the outlet hole on most plastic tanks to be made badly during the process. I always take a clean sharp drill and pass it through the hole, turning it by hand. Start with one that fits decently and clear the little imperfections in the plastic, then I go up one size to open it a bit and give the oil a bit more room to find its way out.

[Coyote]

I guess I haven't owned enough old 2 strokes. 1975 GT550, 2X 1976 GT550 and one 1977 GT750. I have never seen ANY type of filter in these tanks. Just a hole in the top for fill and a hole in the bottom for flow.

[Suzsmokeyallan]

Its the older metal tanks that carry a filter on the outlet as well as a removable cup like a petcock.

[Suzukidave]

Just to take a possible problem out of the loop i put a fuel filter in my oil injection supply line .

[pearljam724]

Just to take a possible problem out of the loop i put a fuel filter in my oil injection supply line .

What did you use, a pancake filter ?

[Suzukidave]

I cannot see why one like that wouldnt work but i just used a regular medium sized filter that fit the oil supply line .

[ConnerVT]

I would be nervous using a filter designed for gasoline on the oil supply line. Oil (obviously) has a much higher viscosity than gasoline, and could prove to be much more restrictive to oil flow.

Then there is the failure mechanism. When a gas filter plugs, what is the worst that could happen? The gasoline doesn't flow, and the engine stops. When an oil filter plugs? No oil to the engine, but you don't know that there is a problem until the engine stops, and won't run again until major repairs are done.

[Cliff]

I'm with ConnerVT on this one. The oil pump is gravity fed and I doubt it can pull any oil through the filter. I didn't have a problem for 40 years without any type of filter!

[Suzukidave]

It is possible my K engine does have one of the oil pumps with the 3rd piston to draw from the tank but if not the oil doesnt seem to have any problems flowing threw it . But i dont want to harm anyones engine with what i may be doing so for sure if you do put in a filter keep a eye on the flow to make sure its working .

[pearljam724]

I would be nervous using a filter designed for gasoline on the oil supply line. Oil (obviously) has a much higher viscosity than gasoline, and could prove to be much more restrictive to oil flow.

Then there is the failure mechanism. When a gas filter plugs, what is the worst that could happen? The gasoline doesn't flow, and the engine stops. When an oil filter plugs? No oil to the engine, but you don't know that there is a problem until the engine stops, and won't run again until major repairs are done.

I was thinking the same. However, I have seen and used pancake filters that are less restrictive than a storm door screen for example. Thinking, if someone used that type of pancake filter. I could see it not restricting too much flow. But, at the same time. Not seeing it worth the risk of any restriction if it's only going to stop larger debris.