V750 sport

1st message on the forum! - so I have been running one since the mid eighties with the twin disc upgrade. Only major breakdown was the timing gears breaking up resulting in a engine strip down to clean out the crap - thankfully the top and bottom end got away without damage. Paul Harris managed to source a NOS set of gears which had been sitting on a shelf in Italy for the past 30 years so got the thing up and running again. However there has been a niggle which I want to float past members to see if anyone has diagnose and fixed a similar issue.

When the starter motor is engaged there is a significant voltage drop resulting in the starter motor being sluggish on a fully charged battery. I have done the usual - cleaned the commutator, brushes and magnets and I have run it on the T3 and the starter motor turned over with no big voltage drop so the issue is not with the starter motor - so the question is where is the current leaking from or is it old oxidized wiring creating a large amount of resistance?

As you know the starter circuit is very straight forward involving a switch, relay, solenoid, motor and a fuse in the circuit so it has always been a mystery to me so if there is a member who had a similar issue and cracked it please post a reply.

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Solenoid perhaps?

My usual test of the starting circuit is to take a wire from the spade connector on top of the solenoid onto the +ve battery terminal. That should spin the motor over. If there is a noticeable difference, then the fault is due to the starter circuit wiring. The feed to the starter relay is the usual problem. The answer is to run a new feed to the relay power feed. The standard arrangement goes through the multi connector and ignition switch causing resistances. On my Spada I ran a wire from a permanent live in the fuse box to the centre terminal on the starter relay. I’m not sure if this option is available on the V7 sport? The alternative is to take a feed direct off the battery +ve, through a fuse and connect it to the centre terminal. This is how I did mine

Thank you Axle and Don - I will get weaving with the wiring suggestion focusing on the feed to the starter relay and should that cure it I will simply leave the wire in situ to the fuse box - if it doesn’t I will simply follow the steps in Axle’s link and post the result.

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