Some time ago I wrote a post about repairing the oil injector lines used on the GT750, and indeed the sort of oil injector line used on most of the late 1960 through 1970’s Suzuki two stroke models. You can find that article here. Assuming that the nylon oil lines themselves were sound, the key obstacle in repairing these lines has been the lack of a replacement option for the check valves located at the end of each line. These are obviously now old, they are easily damaged whether as a result of ham-fisted cleaning attempts by previous owners, or due to corrosion, and like any mechanical device they inevitably wear out. When these valves start to pass, injector oil drains through the injector pump into the crankshaft area and can potentially cause serious damage to the piston and connecting rods due to the risk of hydraulic lock. As well, leaking valves also will cause excessive smoking when the engine is first started. While all of these old two strokes smoke to some degree, from a ‘good neighbour’ perspective ideally it should be minimised if at all possible. A photo of what they look like disassembled is to the right. Just ‘click’ on the photo to see a larger version.
Recently, new manufactured injector valve ends have been offered for sale by David Foxall in the UK who sells them on eBay (see this link or this link) and I did seriously consider buying some from him but so far at least have held off for two main reasons:
- I had a few questions and he was not very responsive to my queries, but most importantly,
- the experiences of others who had bought them seemed mixed.
The two together gave me reason to pause, and so more time passed while I continued to splice and or swap good used valve ends for bad ones as per my original article. Then a Sundial member using the name ‘Vintageman’ mentioned in a post that he had used a Kawasaki OEM part 16128-009 which seemed to work for him. Needless to say, I bought a few to try out and am pleased to confirm that indeed they appear to be the same as the original Suzuki part in every respect that matters. While I was not able to accurately measure the crack pressure (the pressure at which the ball lifts from the seat), dimensionally the Kawasaki valves are the same as the Suzuki ones. When fitted into the nylon line, with the metal collar reinstalled they are oil tight and so far at least, they do not seem to leak.
The instructions supplied by David Foxall for the installation of his replacement valves, and which he very generously provides for download on his website, work well whether you buy from him or opt for the Kawasaki version. I also have them available for downloading at this link. While as yet I haven’t bought any of David’s valves, I may do so at some point just to compare them. Given his are from the UK, due to exchange rates with the Canadian dollar David’s are a bit on the expensive side, but with a bit of luck the value of the British pound may drop further due to Brexit, making them more affordable for overseas buyers like myself ! In the meantime, I have generally bought mine from Kawasaki in the US where they seem to be readily available and are a reasonable price even after converting from USD to CDN$. Kawasaki here in Canada seem to never have stock on hand, which is annoying, but as with Suzuki here in Canada is all too common.
I now have over 2000 miles on a rebuilt set of oil injector lines using the Kawasaki valves which are installed on my 1972 J (called the ‘Oily Purple’ which you can read about here). I am pleased enough with how they have worked that I am now in the process of repairing a few more sets to be used as replacements on other projects I am working on – the next one being another 1972 J model which you can read about at this link.