Oil Calibration

I'm afraid that it's not all that simple, Tallyman.

Mikuni (or similar) oil injection systems are variable. They can be as low as 100:1 at idle (as to not foul the plugs) to as much as 20:1 at full throttle. This is very dependent on what type and size of carburetors are used. If you look at the fuel flow curves for a mikuni VM carb, you'll notice that it's not linear. For the most-part, there is progressively more oil delivered (by ratio) as the throttle is pulled. Arctic Cat gives oil consumpsion tables ( in cc's per 2 min period with the oil lever fully actuated) in their manuals. This is mostly to confirm, or perhaps troubleshoot a faulty system. Pump synchronization has always been by means of aligning rigging marks, not by trying to achieve an "ultimate" fuel /oil ratio.

Luckily, you've adjusted your oil system to the fat side. I can't see how the Manufacturer's technical information can been wrong after so many years.

Stick to OEM specs unless you REALLY know what you're doing.

Tallyman,

I can see what your dealer is trying to tell you, but there's more to fuel / oil mix than there was in the old days. An actual ratio doesn't mean all that much anymore, at least not enough to be worried about it.

When the engineers at Polaris USA designed the engine that's in your sled, they had specific design requirements for the oil injection system for that PARTICULAR engine. Amung them were 1) mechanical lubricating qualities and quantities needed to adequately lubricate the intenal components. (Don't forget that there may be some oil pumped directly to some bearings, or other critical components of the engine, which is later mixed with the incomming fuel charge in the case) 2) emissions 3) reliability (plug fouling, exhaust valve deposits, etc.) 4) driveabililty / performance. (The stoichiometric ratio for gasoline is 14.7:1) Adding an excess amount of oil at any given throttle may bog down your engine, or otherwise alter this ratio.

Once they determined what they needed, they used a pump that would give them exactly what they needed... plus some, as a fudge factor. These pumps are very precise metering devices, but they need a reference point, which is the rigging marks on the pump housing and lever. Align those marks, and the pump does the rest.

For example: A 2000 Arctic Cat ZR500EFI requires that at 3000 RPM and the pump arm fully actuated, that there be 11.275 to 14.122 cc's of oil pumped into the engine. Yet a 600EFI engine only requires 9.224 to 11.558 cc's. ??? Does this all make sense? Not really, because you'd expect that the 600 engine need more oil, as your burining more fuel, and making more power. The people at Suzuki somehow figured that out. Each engine is different.

I don't want to go on about this subject, other than to say that unless the manufacturer , not the dealer, tells us otherwise, either by information contained in the factory service manuals, or additional technical information contained in service bulletins, etc, we should have no reason to doubt them. I don't claim to know more about this than the design engineers, so I believe what they're telling me. It hasn't let me down yet.

Your initial set-up of 100:1 does seem off by quite a bit. That means, that you processed 100 litres (26.42 us gals.) of fuel through your sled before having to add one litre (1.06 us quart). Was the pump rigging off? What else did your dealer say?

This really shouldn't be all that complicated. I agree that the alignment marks are a good place to start. Also not going to disagree with avtech's process of setting them. But as Tallyman mentions, at the end of the day, somebody curious about their oil consumption SHOULD see something like 50:1 .......on average (as observed after several tankfulls). I have personaly observed averages anywhere from 40:1 to 70:1 on my own sleds (mostly Polaris) over the last 35 years, have never had an oil related failure of any kind. If you feel like you want/need to burn a little more or a little less, then of course you are on your own from an engineering standpoint - but this is where you would make your adjustment.

By the way, many of those pumps have a second mark on the lever - one that is supposed to line up at WOT. Have never yet seen a set up when both marks line up when they are supposed to (first mark at idle/second at WOT).