[mt700a1]

This is just one case study, but I had that hot start problem for years until the mystery was finally solved by replacing the starter motor. The bike started very easily when cold, but once it was somewhat warmed up, it would not start. It ran fine all day, it just had a very hard time re-starting with the starter motor once warmed up. I could push start it easily, so I used to park my bike where I could just roll down and push start.

I changed the battery, spark plugs, ignition coils, etc. but the problem persisted. There was one thing I did after which the hot starting issue completely went away. I replaced the starter motor. The hypothesis was that the starter was drawing too much current due to some kind of internal failure, and there wasn't enough battery power for the sparks or rest of the electronics on the bike. Starter was not turning more slowly when hot, so it took me a while to guess that something might be wrong with it. I looked up the parts diagram and noticed that VN800 starter had the same part number, so I bought a used VN800 starter and put it in my 85 VN700. It should work with 750s too but you should check against the diagram to be sure. It's been over 10 years and I have never had the hot starting problem again.

 

[Spockster]

If we knew how many amps a good starter draws versus a worn out starter, we could test for it.

Have to test mine some time. Just hook the load tester up and start it.

That's classic for a shot starter, works cold, but no hot starts.

 

[Vulcan_Frank_750]

This is just one case study, but I had that hot start problem for years until the mystery was finally solved by replacing the starter motor. The bike started very easily when cold, but once it was somewhat warmed up, it would not start. It ran fine all day, it just had a very hard time re-starting with the starter motor once warmed up. I could push start it easily, so I used to park my bike where I could just roll down and push start.

I changed the battery, spark plugs, ignition coils, etc. but the problem persisted. There was one thing I did after which the hot starting issue completely went away. I replaced the starter motor. The hypothesis was that the starter was drawing too much current due to some kind of internal failure, and there wasn't enough battery power for the sparks or rest of the electronics on the bike. Starter was not turning more slowly when hot, so it took me a while to guess that something might be wrong with it. I looked up the parts diagram and noticed that VN800 starter had the same part number, so I bought a used VN800 starter and put it in my 85 VN700. It should work with 750s too but you should check against the diagram to be sure. It's been over 10 years and I have never had the hot starting problem again.

I just put in NGK Iridium spark plugs and completed the pickup coil mod. I've only tested it today with the engine being hot but it starts up beautifully. So much better than before. Looks like my starter is still OK.