I'm not sure this is going to work but I'm attempting to fit a Kubota alternator in place of the dynamo on my Viper. I know it's been done before but I've never seen a photo or explanation of the best way to do it.
After raiding the scrap bin at work for some scrap alloy and spending a couple hours at the lathe here's progress so far.
Still a little work to do but with any luck it'll fit though I suspect the pulley/belt cover will require a little modification.
Model 100 = Universal one wire self turn on unit for conversion or OEM applications. Model 200 is replacement for Kokusandinki units as found on tractors & refrigeration units. Model 200 = Kokusandenki OEM unit repl. for GP9905 / GP9906 / GP9907 Lester # 10930 Model 300 = unit without integral regulator. Has long lead wire for external regulator.
I would prefer the Model 300 without the internal regulator but yet to find that version retail, the Model 200 version is available retail.
14A version would give at 12V 170W, so plenty of juice in comparison to the std Lucas alternators and very close to the high output single phase Lucas versions. The 20A would be 240W and 3 phase so beats the Lucas 3 phase. Only issue is they do not give a rev number for the output, but as they are fitted to diesel generators this should be at a lowish rev number as these are limited to 3 to 4k rpm.
Belt arrived today, fits great and there's a healthy charge showing on the a ammeter. A little fabrication is required to get the covers fitted but I'm pretty happy it all works. �17 Inc postage and a bit of time on the lathe is pretty good for a belt drive conversion in my eyes, bit of a shame to cover it up.
Now I just need to rebuild the mag. Fitted a brightspark easycap which has helped with cold starting but the last 2 evenings the bike has cut out and refused to restart once hot. Runs great as long as I don't go further than about 15 miles!!
Questions: 1) What regulator / rectifier is that? 2) Obviously, you went 12v, but did you stay pos (+) earth? 3) No provision for a belt tensioner.....so the tooth belt needs to be spot on.. What is the front and rear pulley full description and belt size?
I'm thinking of doing the exact same thing. eBay in us has plenty of Kubota alternators for $67 US. Just need to figure the rest of the parts.
Could the housing be machined so that the alternator doesn't sit in it concentrically? That would mean the pulley would be off center and belt tension could be adjusted the same way as the stock set up.
Felt a little bad about butchering the inner belt cover but it wasn't in great condition to start with. I turned an extended crankcase stud nut to use as an upper mount having removed the old upper mount that no longer fitted due to the increased diameter alternator compared to the dynamo.
Also had to make a new outer battery strap, the original was a casualty of an early test ride. Unfortunately the flat bar I had was a little thicker than the original but it'll do for now.
Aye, I decided to go back to the v-belt, I misread the chart when selecting the belt size and the T5 belt is a little on the light side so I've reverted to the V-belt for now until I get time to build up a stronger set up. I'm also curious to see how the alternator performs at the current speed ratio. I'm thinking of speeding it up to increase the current at lower engine rpm but since it was designed for a small diesel engine I'm wary of having it run too fast for fear of overheating it. Don't know if anyone else has an opinion or experience of this?
I haven't a rev-counter fitted at the moment but it's on my list of things to have a look at over the winter. I also need to fit a new regulator as the one currently fitted has given up, I think it happened when the live feed to the battery fretted through on a longer ride into the borders. The fuse at the battery blew but I didn't have one at the regulator so I'm guessing that the prolonged short is the cause of the failure. I've bought a cheap Chinese scooter rectifier which seems to work but we'll see how it lasts after a few miles.