I was having problems with holding charge in the battery while out riding. I believe it is the result of having fitted electronic ignition and then adding a GPS. The problem really started with the addition of the GPS, which drains the battery within 35 Kilometres of leaving home. Switch it off and all is well. So I reckon the electrics were running at full capacity and the GPS was the tipper. After much deliberation, I decided to fit a higher output alternator. Beefing up the DC side can only be a bonus anyway, so the decision was made.

I found one in the Hitchcocks catalogue. Lucas. Stator and rotor. Expensive but necessary I thought. I ordered it.

I did some research. I’ve never refitted an alternator. I found a few video films on Youtube and asked around on the Royal Enfield forum. Feeling fairly confident, I set to work.

The footpeg and footbrake lever have to come off. Then the primary cover. The oil spill is spectacular. There is no drain plug on the primary so the cover comes off and the oil, well, ATF, just pours out along the entire length of the case.

I locked the primary chain in place with a block of wood wrapped in an oily rag. It’s easy, just rest the wood on the inside of the primary chain and turn the big nut holding the rotor in place. This action jams the wood between the chain and the sprocket at the clutch end and the whole thing locks up. I carried on and unscrewed the rotor. Then the stator. 3 nuts and don’t forget the washers. Then I disconnected the wiring from the loom and eased the wires out of the primary casing through the grommet. The stator can now be pulled. And then the rotor.

Time for tea and a fag, I thought. One has to nurture the inner man.

Duly revitalised, I returned to the shed and mounted the rotor. Again, use the wooden block to jam up the works and tighten the retaining nut. There’s a spring washer under that nut holding the rotor in place so give it no mercy and really get a good purchase.
On to the stator.
A note here. The high output stator from Lucas will require the OEM spacers on the mounting studs to be in place. I saw a video where the spacers had to be removed from the mounting studs due to the thickness of the stator.
I had also measured the diameter of the rotor and the internal diameter of the stator. The difference is 0,5 mm. Which means that one has 0,25 mm clearance all the way round. Not much to play with. Luckily, The Lucas stator has soft plastic or rubbery cushions fitted in the bore on either side of the pick up blocks that are the stator. So you don’t have to fiddle with feeler gauges. Smart. Mount and fasten the nuts and washers.

The wires leading from the stator should be on the outside and at the top. If you didn’t get that right, take it off and do it again. Then feed the wires out through the grommet.
The hardest part of that was getting the cable sheathing through the grommet. This required more tea and a little profanity. The truly frustrating part was, that the connectors on the wires were of a slightly larger size than the originals, which means one has to expose the female connectors and prise them open slightly to get a fit. Not easy with a confined space to work in and hands like shovels. Finally, it all fitted and the connectors were covered.

So far, so good. More tea, a smoke break and pat the dogs who had been following my progress with great interest.

Back to work then. While I was there, I adjusted the primary chain tension. Easily done and the primary case was off anyway, so why not? Cover on, brake pedal on, footpeg on. Then fill the primary with ATF and clean up the mess and tools.

Job done, I decided to start the machine. Thumper fired up on two kicks. The headlight works, the indicators work. I measure 13.2 volts at the battery at running speed. All seems to work.. Success…

..except the brake light and tail light. There is power to the brake light but it is weak. The tail light refuses to shine.

I’ll have to investigate… Oh, the joys of owning a Royal Enfield.


Update: 06-09-2015

I found the problem. Just a loose earth connection to the rear light. I loosened it off, gave it a wriggle and, hey presto, I have lights again. This will need a more permanent solution later in the winter but it works for now.