imported post
imported post
The by-pass tube which is located inside the oil filter forces the oil to flow through the filter element unless the pressure across the filter element exceeds the opening pressure of the by-pass valve. In the event that pressure differential across the filter is sufficient, the by-pass valve opens and some (or all) of the oil flows through the by-pass rather than through the filter element.
If the by-pass tube is missing, all oil flows past (by-passes) the filter and no filtration is accomplished.
The purpose of the by-pass valve is to provide oil flow to lubricate the engine in the event that the filter is restricted excessively as would occur if the filter were not changed for a long time. By-pass normally takes place when-ever the engine is cold because the oil is too thick to flow through the filter at anywhere near the normal rate. If the by-pass valve were replaced by a blocked tube the engine would be starved of oil flow during cold operation and camshaft bearings would suffer.
IMO the reason for the high oil pressure relief valve setting is to allow for sufficient oil flow when oil is cold (and thick) because the oil passages to the head are small and long. The reason for the small diameter oil passages to the head is likely to reduce oil flow to the head to avoid flooding the valve spring/stem area with oil which can tend to increase oil consumption despite the use of valve guide seals.
Soap-box mode: I am frequently told that my position on oil weights is ridiculous which amuses me as the position is held most firmly by those with no training or experience in engine lubrication systems or machine shop practices. In my view, people tend to run too heavy an oil. By heavy, I mean to large an SAE number. Frequently 20-50 is chosen when 10-40 or 5-30 would be a far better choice for the KLR. This time of year a zero-30 would work nicely (again, IMO). Consider that the KLR crankshaft uses rolling element bearings which need only a small oil flow and no pressure because a oil wedge from oil supply pressure is not required. The camshaft bearings are under low loading and so require only an oil flow for cooling and clearly do not require an pressure supply oil wedge. This kind of operation is typical of most aluminum head cars as well.
What is not good is to run a heavy oil which fails to flow effectively to the camshaft bearings and lobes for a period of time while the engine is warming up. This can be really nasty! We completly fried the camshaft bearings in a Dodge 2.2 as a demonstration with 30 weight oil at minus 30C. There was smoke coming out of the oil filler cap hole and the camshaft was screaming in the bearings so loudly that it almost drowned out the sound of the engine. The camshaft and bearings were finished long before oil warmed enough to start flowing.
Choose your oil wisely. Kawasaki recommend the viscosity range for a reason. It is OK to use a 5-30 where a 10-30 is recommended or, a 5-40 in place of a 10-30 but don't use a 20-50 in that temperture range.
I just love to hear from people who have never machined a shaft, replaced a bearing, etc. as to how they know better........ Ah, well. It's their machine and they are quite free to do as they wish. I just hate to see someone wreck something due to bad advice.
Soap-box mode off,
Norm
P.S. I'd change the oil and ride until the by-pass tube arrives, but that's me. Consider how many million motorcycles with similar over head cam configurations runfor longlives and don't even have an oil filter.
You better do what you feel best. Parking it until the new tube is installed isn't a wrong answer.
