Starter problem with an old Honda VT750C Shadow motorcycle?

Question

1983 honda VT750C shadow motorcycle cranks and starts fine when engine is cold,but when fully warmed up the starter seems really strained to rotate engine and push through the compression stroke. It is worse on very hot days when engine runs hotter, it never overheats. It has never failed to start ,but sometimes I have had to release the starter button momentarily and push it again to get the engine to rotate and start. A local mechanic is trying to convince me that this normal for this model motorcycle. It has a new battery and very recent starter brushes replacement. Anybody familiar with this particular bike? Thanks

Answer 1

Make sure the terminals are tight at the starter motor, starter solenoid (the battery positive cable goes to it) and battery.
Make sure the starter motor mounting bolts are tight (that's the ground for the starter motor).
Make sure the battery negative cable is tight where it attaches to the frame (or engine).
Check the starter motor (when it warms up due to the engine temperature, any ware will lessen it's performance).
Remove the starter motor (stuff a rag in the engine hole to prevent dirt from entering).
Attach the starter motor cable.
Attach a jumper cable to the body of the starter motor and the battery negative, or an engine mount bolt.
Hold the starter motor firmly.
Turn on the key and press the starter button.
The starter motor should have enough torque to want to jump out of your hand.
If it feels limp, it should be replaced.

Answer 2

He is right.. four stroke motors( especially singles & twins)
quite often have decompression lifters on them... the Shadow has a hydraulic adjuster on the valves (from the look of the exploded diagrams I have) this would not be "pumped " up when cold. but would have hydraulic pressure when first stopped when hot... so the starter is trying to turn the motor over on the compresion stroke...( ever tried kick starting an old single cylinder bike with out the decompresion lever pulled in)... this would be a big ask from a small 12 volt starter motor..

Answer 3

None whatsoever, the engine was based on an existing design that was already very reliable (vt500) and the rest of the bike is all top spec honda build quality. They aren't particularly slow either given the nature of the bike you wouldn't want to go much faster anyway.

Answer 4

1983 Vt750c