Suzuki 2 Strokes

Thought I had this all sorted out, but getting her fired up for the first time this year has brought me to a head-scratcher.

Periodically through the season, I like to switch from a red injection oil to a blue oil (then later, back to red) to get that warm feeling inside that the oiling system is working as it should. So, at the beginning of this season, it was time to switch to blue oil.

Took the T500 out for a ride, and to my dismay, found only 3 of the 4 oil lines to be blue. The line to the left bearing was no blue oil in it at all. The other half of that line (to the cylinder) looks just fine. No air bubbles to be seen in any of the lines.

Just came from the garage, where I pulled everything apart. Removed all 4 fittings and the pump from the engine (inspected all banjo bolts, no obstructions), and drove the pump (with arm pushed to full throttle position) with my electric drill. Could get oil to drip from the three good banjos, but not the left bearing one.

I replaced the oil line with another I have (pretty trashy), and I again had the same result. Was able to fill the new line with oil, but only the cylinder line, not the left bearing line.

Putting the original line back, I was able to (finally) fill the line by using some M6 flange bolts/nuts to "close off" the three other banjos, leaving only the left bearing banjo open.

With that story told, I have some questions. Hopefully those of you who have gotten your hands oily on the T500 can give me some input (the triples guys know a lot too, but I want to keep this to T500 hardware, as the differences are significant).

First, is it possible that the oil pump itself is the problem? The left bearing output is the longest length oil line. Could the pump just only have enough pressure/flow (?) that the longest line is getting starved of oil? I have noted the slightest amount of oil on the top of the pump, where the tach cable attaches.

Second, (and more theory than anything), where does the oil go after the left main bearing? The oil injected into the cylinder obviously exits eventually in the exhaust. But where does the bearing oil end up?

I tested my oil pump using a drill to drive it and got poor results initially.

One thing I did with my oil lines (this bike had been sitting for a very long time) was to rod each of the lines with some small gauge insulated wire. The previous oil had turned to a very viscous gel-like state. Thus I was only getting decent oil flow out of a couple of the lines. After I had cleaned them all out I got much better/more even flow. I put a different colour oil through each time and could see the improvement after the de-sludge.

I tested my oil pump again using a drill to drive it. There was oil dripping out of all four lines and it seemed more even. I had an issue with air bubbles (I believe these come from the pump bottom seal being stuffed (it was rock hard and literally slid off the shaft when I removed it to test the fit). I'm awaiting replacement seals to test it all again.

I looked at where the oil injects in the case and can see that there are two holes in each of the outer bearings and thus the oil passes into one of the holes. I assume it then pressurises the bearing and oozes out pass the seal and ends up being combusted. If the crank seals are in different stages of wear/age then I suppose it may bias how the oil is distributed.

I'm very keen to hear of more experiences.

Geoff