Is the Yamaha Star Venture service manual correct or is it wrong, there has been a rumbling that the Star Venture service manual in not correct and apparently that determination came from the section of the manual that trouble shoots overheating.
The service manual lists a total of 23 possible causes for overheating 8 of which are aimed solely at liquid cooled engines. That means the other 15 possible causes apply to both liquid cooled and air cooled engines. This section of the manual covers multiple engine designs so if you had an issue with overheating you would go down the list of possible causes, so if your engine was liquid cooled all 23 items on the list could apply, if your engine was air cooled as on the Star Venture you by pass the 8 specific items that only apply to liquid cooled engines and you check the other 15 possible causes. Not every possible cause applies to every engine, some liquid cooled engines might not have an oil cooler just as some air cooled engines on smaller displacements might not have an oil cooler, so you would skip that possible cause.
It is easier for Yamaha to write a trouble shooting section that covers all their engine/system designs than it is to have to write specific sections for each engine/system combination they build.
The Yamaha Star Venture service manual is correct as written.
Case in point go to the brake trouble shooting section one of the items in the list of possible causes of a brake issue is to check the drum brake shoe and another is to check for a worn or corroded brake drum. Clearly the Star Venture does not have brake drums and brake shoes because it has disc brakes.
That is just another example where you go down the list and you disregard the possible causes to do not apply to your brake system.
Now if you go to page 16 of the Troubleshooting section at the top of the page:
Troubleshooting information provided here does not cover all the trouble symptoms, possible causes, and remedial actions. Some items may not apply depending on the model.
Use this information as a guide and quick reference matrix when preforming basic troubleshooting. Refer to the applicable Service manual for detailed information on checking, adjustment, and replacement.
In other words the trouble shooting section was written to cover multiple vehicles of Yamaha's line up.
When it comes to oil changes the Yamaha Star Venture service manual is correct on the amounts of oil to add to the oil tank and the engine crankcase for a dry engine, for changing the oil without changing the oil filter and changing the oil with changing the oil filter.
Failing to follow the proper procedure spelled out in the service manual could lead to potential engine/primary/transmission damage if you fail to follow the service manuals instructions on how much oil to add to the oil tank and the engine crankcase.
The service manual is very specific:
a. Pour only 3.2 US qt of the specified amount of recommended engine oil through the filler hole.
b. Fill the crankcase with the remaining oil quantity.
That is pretty specific, If you change the oil but not the oil filter you add 3.2 quarts of oil to the oil tank, the remaining 1.98 quarts of oil are poured into the crankcase.
If you change the oil and the oil filter you add 3.2 quarts of oil to the oil tank, the remaining 2.4 quarts of oil are poured into the crankcase.
The owners manual is on the vague side on the proper methods of changing the oil. It is very brief and says to pour 2 quarts of oil in the crankcase and 3.2 quarts of oil into the oil tank. It has a short tip section that says if you change the oil filter you will have to add more oil but does not say how much oil to add and is not clear about where to even add the extra oil. That is in conflict with the service manual. The owners manual even has you adding oil in the reverse order from what the service manual says. I suspect the owners manual was written by some flunky in the office who looked at some tech documents and wrote the owners manual in his/her own interpretation.
My advice to ensure you are adding the proper amounts of oil in the oil tank and the crankcase is to follow the service manual where it spells out exactly how much oil is poured into the oil tank and the engine crankcase. The only place the owners manual and the service manual line up in full agreement is adding 3.2 quarts of oil into the oil tank. Beyond that the owners manual is vague and leaves you guessing how much and were to add the additional oil when the oil filter is changed.
My reason for saying to follow the service manual is because any service technician when working on the motorcycle is going to be following the service manual, they are not going to go get the owners manual and try to use it to service the vehicle. If there is a conflict in a procedure between the owners manual and the service manual always come down on the side of the service manual because the service manuals will always be more detailed and is the manual used by servicing dealers.
Yamaha has provided the correct information and procedures in the service manual if people choose not to follow them that is on that person not Yamaha.