The Art of Flow Control

How get the optimal oil flow rate....

 The TUTORO Auto Workshop Manual gives guidance on this on page 33 

9. Open the valve again 1-1.5 turns to set a flow rate.

10. Go for a short test ride. After 20 minutes stop and take look at your chain. Adjust the flow rate if necessary.

In short that's exactly  what you need to do - take short rides and adjust the flow until you get it "just right". 

Setting the flow control valve then going for a long ride before checking the flow rate is correct is almost bound to be problematic.

The correct flow rate depends on many factors

  • What temperature is it?
  • How hard or soft are the suspension settings?
  • On Road or Off Road?
  • Is it wet or dry?
  • Is the oiler in a position where it can be warmed by the engine/exhaust?

But the Workshop Manual says 1-1.5 turns, right? so that must be the right flow rate! 

Welcome to the analogue world...its not a one size fits all, just a good place to start. So before you just set the dial to warp factor 9 and ride off into the wide blue yonder, consider these variables.

The ambient Temperature, the Bike, the Surface and the Weather

  • Why does the Temperature matter? - Oil will flow more slowly the colder it gets so you need to increase the flow control valve setting as the temperature drops (obviously you also need to reduce the setting when the weather gets warmer).
  • The Bike - Sports bikes have harder suspension than Cruisers - Harder suspension will activate the Auto more frequently than softer suspension. Due to the design of the Auto (which averages the activation frequency out) this matters less than you might think but its a factor to consider, albeit a small one.
  • The Surface - On Road or Off Road? - the same factor as the suspension hardness comes into play here, activation frequency average will be higher Off Road than On Road. One thing of note here is that you actually want a higher oil flow Off Road than On Road because its a high contamination environment - mud and water will get onto the chain so extra lubrication is extremely beneficial. Just be aware that if you bike "lives" Off Road and you then take it on a long ride On Road the flow rate maybe wrong.
  • The Weather - this is a big factor, as mentioned above there is nothing like rain water for washing lubricant off a chain. In fact due to the higher speeds usually travelled whilst On Road, the spray practically "power-washes" the chain and sprockets so if you want to get the best life from them you need to turn up the flow rate when riding in the wet.

and finally..

  • The Install Position - For instance on a KTM V twin the exhaust may pass within a few inches of the oiler reservoir - this warms the oiler and thins the oil making it flow faster. The install position creates a "micro-climate" for the oiler. A quick check for this is...take the bike for a ride then stop and feel the oiler reservoir - if it feels warmer than say the rear number plate, then you have a micro-climate and will need to reduce the flow rate compared to an oiler that is not being warmed.  


In Summary

You can see how all the factors above effect what flow rate is right for your bike. The fact is that 2 identical bikes, riding on the same day, in the same weather, on the same roads can have different flow rate requirements merely because the oiler units are installed in two different places. 

But if you follow the advice set out in the Tutoro Auto Workshop Manual you can quickly get it tuned in just right.

Take a number of short test rides and look at the condition of the chain, bear in mind that if you cranked the flow control valve open to full bore and got the chain really "wet" with oil it will take a while for the chain to get rid of the excess oil.

So if you have really soaked the chain, turn the oiler off for a while until the chain is looking dry then start again with a minimum of flow perhaps just 1/8th of a turn open. 

If the chain appears to be staying just right with a sheen of oil on the rollers then you have hit the sweet spot - now leave the flow control alone.

If the chain is still looking dry, despite the flow control valve being open 1/8th of a turn, then increase the setting in 1/8th-1/4 turn increments of the flow control valve until you have reached the sweet spot.

As detailed above where this sweet spot is will depend on the variables above.

For example

Ambient temperature = 5°C that sweet spot might be 1.5 turns open.

At -5°C it might be at 2.5 turns open

At 20°C 1/4 turn open

At 30°C 1/8th or maybe 1/16th turn open

Please bear in mind these are EXAMPLES don't take this as the exact right setting for your bike at these temperatures - they are just to illustrate the wide set of conditions that the flow control valve can deal with.

One last note - like any "needle" type valve the flow control valve's smallest incremental changes are when it is almost closed (ie in the last 1/2 to 1/4 turn).

Also be aware that the flow control valve is not a "digital" linear control i.e. 2 turns open is not twice the flow rate of 1 turn open but rather more in the region of 3 times this is a function of the gap between the tapered cone of the flow control valve widening as it emerges from the valve seat and allows the use of heavier oils like Plus25 formulated for tropical climates.

Basically anything other than fully "Off" is "On" to one degree or another.

Once your flow control rate is set up you will probably only adjust it from a winter setting to a summer setting or maybe when contemplating a long ride in the rain.