Hey all need some advise with my 1997 748 so as discussed a while back its on going project and it has a rebuilt engine amongst many other things. I noticed that it was miss-firing the other day when coming off the throttle this then led to it missing firing through the rev range the obvious loss of power before ultimately cutting out and leaving me at the side of the road for a few hours waiting for recovery. Once I got the bike home I put it on charge to see if the battery had flatten which it had (this is a new battery) so I'm guessing its the stator or the stator regulator as the battery was unable to maintain charge. The bike now starts and runs but I didn't leave it running long enough to run out of electric. I've had a look around and have seen two different types of stators one with a plug and one without? Any advice on which it would be without stripping it down ( I don't have a lot of space to have a bike in bits). Also any tips on what else I should investigate going forwards. Kind regards
First you should check to see if it is a faulty stator or regulator and pay particular attention to the connector from the stator to the regulator. The connector can get corrosion leading to a high resistance. This prevents current getting to the regulator and will generate heat often melting the connector. To check the stator disconnect it from the regulator and measure across the 2 yellow wires with your meter set to read AC volts. Start the bike and you should get a reading of approx 15Vac per 1000rpm if the stators ok. Measuring resistance across the 2 wires will show a very low resistance, only an ohm or so. There should be no reading whatsoever between any of the yellow wires and earth. If there is one of the windings is shorting to earth internally. If the stator checks out good and the wires/connector to the regulator are ok then the problem most likely lies with the regulator.
The regulators are a common problem with these bikes. Definitely worth upgrading to a mosfet regulator if you haven't done so already. Rick's Motorsports sells them specifically for your bike.
it's more the slightly underpar wiring and connectors that let them down Chris, the actual std regulators can last 20 years which is pretty acceptable, to me anyway. it's not the best search system on here, but it's been covered many many times over the last 10 years.
Yep, aware of the issues with the wiring and connections on these machines. The standard unit runs hot and can be a lottery sometimes when they fail. For a couple of hundred bucks, I personally think they're worth the upgrade.
Agreed, my regulator was replaced due to an incident where the battery got broken and leaked acid over it. The replacement is still going strong 23 years later at 52,000 miles. It did suffer the above mentioned connector burnout many years ago but has been fine otherwise.
