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Rebuildable Oil-Lines on a 1969 T350?

Posted: Wed Jul 14, 2021 5:08 pm
by jsjays1
Hello All,

I've been working on the oil lines of my '69 T350 - one of the check valves was seating intermittently, which occasionally caused it to pull air into the line.

Interestingly, unlike all other information I've found for T350's, I found that my bike was fitted with rebuildable check valves on the ends of the oil lines, like Kawasaki oil-lines of similar vintage. I thought that they may have been modified to accept the fittings from Kawasaki lines by a previous owner, but the banjos don't look exactly the same.


In fact, the only place that I have seen similar lines was on Old Japanese Bike's website, on his 1968 T500 project page (see "injector valve" photo here, Those line ends look like an exact match to what is on my bike. I guess it's possible that some models may have used this same rebuildable style through '69?

Anyway, I was able to replace the check ball and spring with parts being sold by "tv4fish" to rebuild oil lines on Kawasaki triples ( ... SwWuNgN4J0, or In case anyone is in the same situation, it appears that these parts are compatible between the bikes. I can't confirm the longevity of the new parts, or whether the oil flow is still appropriate with them, but they got me back on the road for now.

Re: Rebuildable Oil-Lines on a 1969 T350?

Posted: Thu Jul 15, 2021 6:24 am
by jabcb
I have a 69 T500 project bike that has the rebuildable oil lines.
Have an original printed parts manual for the 69 T350 — part numbers are different than listed for later model years.

Suzuki didn’t necessarily make the transition to the later oil line design with the start of a new model year. Most likely switched when they ran out of the rebuildable lines.

The pump is a displacement type, so the pressure to operate the check valve isn’t that critical.
But the ball needs to be a similar diameter so that it seals when closed & allows flow when open.

Re: Rebuildable Oil-Lines on a 1969 T350?

Posted: Sat Jul 17, 2021 6:01 pm
by jsjays1
Hey, thanks for the info jabcb. Yes, that makes sense that they would have carried on with those fittings in production until some switch-over to the later design. Admittedly I can see why they did it too, as the fully integrated part eliminated cutting a couple threads, and removed the crush-washer seal - must have been a bit cheaper.

And yeah, that's also a good point on the pump. With it being a positive-displacement type the flow rate wouldn't be affected by the opening pressure of the check valves would it? Just adds a little extra work for the engine to do if you up the spring strength.

For what it's worth the check balls from the kit sold by tv4fish were a perfect match to my original Suzuki ones - just under 0.125". So if someone else needs to service their lines I wouldn't hesitate to send them that way.