Starting Issue 850 Mkii

[fixitsan]

Thank you all for commenting.

 

I'm interested in the comments about 'frame to engine' grounding. I always assumed as the engine is bolted to the frame (and the battery is bolted to the frame) this is direct contact therefore there is continuity of ground but I'm inferring from the comments that there is some other connector or connection that completes this continuity. If so, where is this?

 

Regards

 

 

A simple test is to measure first the battery voltage from + to -, then measure battery voltage from the battery's '+'  terminal and ground somewhere on the engine, like an alternator or engine casing bolt. The two readings should be close to identical.

 

I learned in the past that just because it's solidly bolted to the frame, corrosion on frame-engine bolts can start to develop high resistance which is enough to limit the amount of current the starter motor can draw.  There should be a thick cable from the battery's '-' terminal and the engine, or at least one from the frame to the engine. It's an unusual fault, and might not be your issue. On my old KZ550 the absence of the grounding wire made the starter turn very slowly

 

As stated already the starter motor could be the culprit, and a jump lead from the battery positive to the supply for the starter motor will tell you if that's the problem. The solenoids themselves can be a problem. so bridging the solenoid terminals to see if the motor spins can eliminate that. Expect sparking when you do these tests, be very vigilant not to let '+' and '-' from the battery touch together

 

Another check can be of the battery voltage when you're engaging the starter, how low does it drop ? If it drops much below 10V then the battery could be old and sulphated. Sulphated batteries can still reach a high voltage when charging, but the plates can be shorted together with crystals which reduces the maximum available current when a high load engages, such as the starter. Some people buy battery load testers to simulate this test

This post was last modified: 11-03-2026, 12:25 PM by fixitsan.