Motorcycle Questions? Ask a Mechanic.
Hi and thank you for your question.
The starter clutch bolts to the back of the generator flywheel so yhou would have to remove the left crankcase cover and pull the flywheel to get to the starter clutch.
Here is a diagram of the starter clutch. Typically what fails are the rollers that the microfiche calls dowel pins and the starter idler gear 2. The damage to the gear is usually on the inner race for the starter clutch. It gets scored and dented and then does not function normally. Inspect the 3 rollers for any signs of wear or damage (flat spots). Here is a diagram of what I am talking about, items 6 & 5.
Yamaha's V4's of that era had a somewhat known problem when going to start the bike when it is hot. For starters, any engine in good shape has more compression when it is up to temp so you are fighting more resistance to start when your engine is hot compared to cold. Also, the starter motor gets hot and creates more resistance internally and looses some of its HP or its ability to start the engine. This will usually amplify or intensify the engine's resistance to starting.
If an inspection doesn't reveal any problems, then you have the sad choice between letting it sit longer after you shut it off or don't take it when you are going to be restarting it in the next 15 minutes.
You could also get your battery checked for its CCA. Most autoparts stores, in addition to most MC shops, are equipped to evaluate the condition of your battery.
If you have any more questions feel free to ask.
Thank you for the additional information.
Honestly, I do not suspect the oil and grime you see are creating your problems. The starter is bolted rather tightly to the cases and the probability of oil penetrating into the contacting surfaces between the starter and the cases that it uses for a ground is almost impossible. Now if oil got inside the starter, which is not likely but more probable than creating ground problems, it would hamper its ability to function. It would be a good idea to remove the starter and inspect it to see if there is oil on the inside. While you are in there, check the length of the brushes as well. If they show wear, which is likely, you should replace them. Statistically being a 1993, it would benefit from getting them replaced.
Let me know what you find with the oil, but I suspect we are still looking for something else.