Skip to main content
000000 000003 000006 000009 000012 000015 000018 000021 000024 000027 000030 000033 000036 000039 000042 000045 000048 000051 000054 000057 000060 000063 000066 000069 000072 000075 000078 000081 000084 000087 000090 000093 000096 000099 000102 000105 000108 000111 000114 000117 000120 000123 000126 000129 000132 000135 000138 000141 000144 000147 000150 000153 000156 000159 000162 000165 000168 000171 000174 000177 000180 000183 000186 000189 000192 000195 000198 000201 000204 000207 000210 000213 000216 000219 000222 000225 000228 000231 000234 000237 000240 000243 000246 000249 000252 000255 000258 000261 000264 000267 000270 000273 000276 000279 000282 000285 000288 000291 000294 000297 000300 000303 000306 000309 000312 000318 000321 000324 000327 000330 000333 000336 000339 000342 000345 000348 000351 000354 000357 000360 000363 000366 000369 000372 000375 000378 000381 000384 000387 000390 000393 000396 000399 000402 000405 000408 000411 000414 000417 000420 000423 000426 000429 000432 000435 000438 000441 000444 000447 000450 000453 000456 000459 000462 000465 000468 000471 000474 000477 000480 000483 000486 000489 000492 000495 000498 000501 000504 000507 000510 000513 000516 000519 000522 000525 000528 000531 000534 000537 000540 000543 000546 000549 000552 000555 000558 000561 000564 000567 000570 000573 000576 000579 000582 000585 000588 000591 000594 000597 000600 000603 000606 000609 000612 000615 000618 000621 000624 000627 000630 000633 000636 000639 000642 000645 000648 000651 000654 000657 000660 000663 000666 000669 000672 000675 000678 000681 000684 000687 000690 000693 000696 000699 000702 000705 000708 000711 000714 000717 000720 000723 000726 000729 000732 000735 000738 000741 000744 000747 000750 000753 000756 000759 000762 000765 000768 000771 000774 000777 000780 000783 000786 000789 000792 000795 000798 000801 000804 000807 000810 000813 000816 000819 000822 000825 000828 000831 000834 000837 000840 000843 000846 000849 000852 000855 000858 000861 000864 000867 000870 000873 000876 000879 000882
English French German Italian Spanish

Navigator alternator replacement

Forums

I know this is an issue much discussed in the past but I can't quite pin down the discussion thread that gives the definitive answer.  My old Wipac alternator has finally died and having already converted the bike to 12v electrics I want to replace it with a modern 12v stator and a new rotor.   From various threads I see that the Lucas RM21 stators is widely recommended as a readily available replacement but these require a 74mm external diameter rotor.   My question is does the 74mm rotor have the right internal diameter and key way to fit on a Navigator's crankshaft?    

Thanks in anticipation!

Nick        

Permalink

Easy answer NO. The Jubilee, Navi, and Electra crank shafts are all 1" so the Lucas type 74mm rotor will not fit ie it is made for a 3/4" crank, no you can't bore it out either, there would be little metal left to be safe. The Wipac rotors do seem to go on for ever, and you can get them re-magnetised if their is any doubt. The RM21 stator will give a bit bigger gap to the rotor but this is acceptable.

Permalink

I don't know if the lightweight stator studs are the same size as the Dommies ,if they are then the RM21 stator is not a straightforward fit. A rotor spacer,sleeves,stepped studs or rethreading the mountings will be needed. Perhaps someone with a lathe and the interest in keeping us going would step in and supply members directly, Anna ??. You've got my order ,3 stepped studs for a dommy please!!.

Permalink

Thanks Alan,really helpful as ever!    I am using your excellent modern rectifier / voltage regulator, should I use the three or two wire RM21 or doesnt it matter?   I am guessing the 2 wire is fine?    Thanks for the heads up Robert - can anyone advise over stator studs?   

Nick

Permalink

Well after a busy Easter I have finally got round to solving the Navigator's electrical problems.   A careful check through the charging system proved that the original, ancient and very battered Wipac 6v alternator had finally died and the modern rectifier / regulator had failed (perhaps as a result) so I bit the bullet and bought a modern Lucas rectifier / regulator and a two wire RM21 and fitted both which has solved the problem.   As Alan points out the original Wipac rotor is slightly undersize giving a circa 12 thou gap but the ammeter is showing a healthy charge rate so it isn't an issue.    As for the studs being undersized for the holes they are so I sourced a length of thin copper tube from my local model aircraft shop for £1.25 and cut three spacers which fitted perfectly so no need for stepped studs!    With the higher output of what is now a late 60s 12v system I am going to experiment with higher wattage headlight bulbs (60/55W H4 Halogen pre focus?) so perhaps I will actually be able to see at night which will be a revelation!   Thanks for the advise - it really helped sort this quickly.   Nick           

Permalink

Nick........think about changing all those filament bulbs for the latest LED versions. Paul Goff offers such replacements. This way any loss of Watts due to the mismatch of alternator chunks will easily be negated by the much lower total power drain when everything electric is being used.

Hi Robert, sadly I've used all the remaining brass tube (not copper as I stated) tube on another job but it is readily available either from Hobby Hangar in Yeovil (01935 422400) or perhaps quicker if you don't live near from ebay for a couple of pounds.   I searched using K&S Copper tube #8133 5/16 x .014 and quickly found some for £4.25 from a dealer near Drifield in Yorkshire called flying-tigercat / Cottage-Craft-RMCE.   I have attached a photo of the packaging which luckily I hadn't thrown out!   Good luck - I found it was a perfect fit over the studs on my Navigator and into the holes on the Lucas stator and centralised it over the rotor without any more fettling.   I hope that solves your problem!    Nick   

 

Norton Owners Club Website by White-Hot Design

Privacy Policy