Forum

[stinkwheel]

It's on my '07 350 classic which has the standard AC/DC alternator fitted.


I noticed this last night that when I turn on the main headlight, I get a fairly intrusive whirring noise from the vicinity of the primary case. This noise is directly dependant on the lighting switch, it goes away immediately you turn the lights off and is not present with the sidelights on. Sounds a bit like someone winding up one of those dynamo torches.


Now it could be  that this noise has always been there and I never noticed before but it does seem new to me. I'll be having a look under there at my earliest convenience to check everything is working ok but it would be good to have any ideas of what exactly I should be checking. 


I should add that the electrics all appear to be finctioning normally and the headlight is nice and bright. I'm running ATF in the primary drive and have been for about 15k miles now.


 


Any thoughts welcome.


 


Scott

[John J]

Hi, It sounds like the same noise you get from a transformer under load. I would check that the stator nuts are tight. Also check that the stator laminations are secure.

[Riggers]

Hi Scott,


I had this problem with my 2000 model.


In my case the 'air gap'on the alternator between the rotor and the poles of the stator had closed up on one side.


 Simply remove the primary chain case, slacken off the three nuts holding the stator, and then retighten making sure that the above gap is not less than 0.15mm (0.006") all round.


It solved the noise on my bike - hope it does on yours.


Good luck,


Tony R.

[Gwilly]

+3 the above, cut a kelloggs cornflake box into 6- 1"x2" strips and fit around the rotor. Just the right thickness to give equal space when tightening stator nuts. gwilly

[Alan R]

Hello again matey---yes, I tend to go with JohnJ on this one. The sound is proportional to the electrical load applied to the alternator. The side lights have very little wattage requirements ( 5w each  ??) compared to the humungus 25W demand that comes on-line from old cyclops up front. I don't know what the rated output for the 350 alternator is but I'm betting it's fairly close to the total electrical load of the bike ?? So it's going to be near max. output when at max loading. Yes, a good mechanical check etc. should put your mind at ease--------------------------------------------------I hope ?  Only teasing.Just a thought, if you have the ability ( and the inclination ) you might just consider doing a reistance check on all the coils. Hitchcocks Technical has a bit on it I think. 

[Alan R]

Ahh--- have just seen Gwilly & Riggers ideas. Yes, that's very good. Hitchcocks sell a special plastic gauge that, aswell as giving you all the info printed on it, it's also the correct thickness to act as the spacer---- item 98240----- at £1.50 + VAT, P&P. Worth the money I think. As Riggers says it's only 0.006"---- about the thickness of an etched line on an Engineers steel ruler.  

[Beezabryan]

I cut a piece of plastic milk bottle to fit around the rotor

[Alan R]

 -----------bottles for plastic milk ?? Do you live near Milton Keynes ??  I meant 55W of course.