S7 Clutch Release Bearing Mod

The VXB 6x14x5mm Miniature Thrust Bearings arrived today and were easily installed in place of the original balls.  I added some moly grease for extra insurance.  The height gain was only a few thousandths from the worn parts, and easily allowed the clip ring to be replaced with room to spare.

Clutch Release Bearing Worry.

I've been getting an annoying clunk when shifting gears on KYL95.  I adjusted the clutch cold, but when hot it seems not to disengage properly.  Consulting the SOF gurus and Sept/October 2010 issue of On the Beam, I discovered that a modern bearing AKL 6 could be placed between the original release bearing races and maintain the original configuration.  Brilliant, except that I couldn't find that model number locally.

Off to trusty eBay with no results.  So I got the dimensions (6 x 14 x 5mm) and went searching further to discover VXB Bearing selling through Amazon.
http://www.amazon.com/Thrust-Bearing-6x14x5-Miniature-Bearings/dp/B002BBKCAE/ref=sr_1_1?ie=UTF8&qid=1336961575&sr=8-1

They might actually be delivered in two days!

Luckily the clutch release bearing can be removed easily without dismantling the bike.  Pulling it out revealed that there's nothing really wrong with it, except some radial wear inside the bearing holder cup.  Since there really isn't supposed to be any radial load, and I can probably attribute that to some numbskull in the past putting a frapping nail in place of the clutch push rod.

 

The release bearing is easily removed.  Notice my clever Viton o-ring seal "glued" to the outside lip of the gearbox.

 

The locknut is knocked loose, then removed, after that the bolt can be removed. 

 The balls look fine.  There's a little wear on the races, but nowhere near anything catastrophic.  With nothing to keep the balls evenly spaced, I'm sure they're bumping into one another, shifting the load on the races.

 

The whole assembly fits together like this and then drops down into the cup.

 

Sorry for the blurry picture, but the wear inside the cup is evident from some radial load on the bearing.

The next installment will be investigating the installation of the new bearing.

Imp Water Pump

I had a terrible time previously obtaining an Imp Water Pump rebuild Kit through US customs the last time.  This time I was determined to obtain the correct parts locally.

The bearings turned out to be a double-sealed variety which are fairly common.
6202 2RS Double Sealed Bearing 15mm x 35mm x 11mm

The seals were a little harder to find, but a tip from a friend led me to look at pool pump suppliers for an AVON type B seal:
16B36

All is back together and working fine.

Sunbeam S7 / S8 permanent magnet alternator conversion (recap)

This is a recap of my alternator build.
(as published in the Sunbeam Owners Fellowship club magazine "On The Beam" issue Nov-Dec 2011)

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I’ve been frustrated with the original Lucas dynamo on my Sunbeam since I’ve been riding it. Neither the MC45O nor the MC45L (that I later purchased) produced enough electricity in a foolproof fashion. I don’t want to have to worry about if there’s enough charge in the battery to get me home anymore, and I want to run the lights all the time. I also don’t want an after-market alternator conversion that does not look exactly like the original. This is why I was determined to create an alternator conversion by myself for a small price. I submit the following to any interested do-it-yourself owners.

I took suggestion from some Douglas and Vincent motorcycle owners who also have problems with dynamos. A few intrepid owners have taken permanent magnet alternators from modern applications and fit them inside the original dynamo cases. One particular application caught my eye while searching online for a suitable solution. There is a simple alternator from a Kubota tractor that measures only 3-1/2” across and a little over 3” high. I bought model APM0001, which was the smallest available. This came as a self-contained belt driven assembly. I tested it briefly before taking it apart to see how easily it produced enough current being turned by hand to light the tail lamp bulb on my bike. Removing the nut and pushing the bolt out easily disassembled the unit, shown in Figure 1. The back housing was discarded.

Figure1

The magnet cup was surprisingly powerful. It all fit nicely into the original dynamo case. There would be two major challenges. Fit the magnet cup to the crankshaft, and then to fit the case back onto the engine block so it all stayed together. I elected to do the reverse of what the Douglas owners had done, and fit the magnet cup onto the shaft first, so that the stator would be accessible from the front of the bike. It sounded wrong at first, but it eliminated so many problems it was worth the effort, in my mind, to machine all the required parts on the lathe. There would have to be an adapter to fit to the end of the crankshaft, which included pins to fix the magnet from rotating independently from the crankshaft. This I spun out of round stock on the lathe to a relatively high degree of precision. I would use the original left-handed bolt so I didn’t have to machine another one. The outside casing would have to be secured to the engine block by means other than the two long bolts originally used, because they interfered with the outside diameter of the magnet. The wires could easily come out the front and affix to the original terminal block. Below is the solution showing the framework cage that was made to hold the outside casing. I could have welded tabs to the casing, but I didn’t want to modify it.

Figure 2

The whole assembly fits together with a specific procedure, it’s not ideal, but it works. (I later discovered that the magnet was so strong, that I needed to fit two of the sealed bearings inside the stator winding assembly to keep it centered with respect to the crankshaft. That isn’t represented in the photographs.)

The cage, at the left of Figure 2, goes on first. The magnet and center bolt (with spacer) then affix to the crankshaft adapter. The spacer holds the sealed bearings from the original Kubota unit, and another outside press-fit spacer makes up the difference between the stator and the outside bearing race.  The fourth arm of the cage assembly encloses the magnet, before the case is slid onto the cage. The pole shoe screws fasten the case to the cage in such a way that it forces the case into the engine block firmly as the countersunk screws are tightened. The stator coil, at the right side of Figure 2, slides into the magnet which is centered by one of the bearings from the original alternator assembly. This took a brass spacer precisely machined out of an old pipe fitting. The wires tuck neatly up against the casing out of the way of the rotating magnet. The outer plate bolts on with 6 screws and then the cast aluminum cover of the dynamo bolts to the outside of the case.

Figure 3

I’m quite pleased that the mechanics of my alternator conversion work well. The next challenge was to rectify and regulate the alternating current into direct current. Normal people would just have converted to 12 volts and put the Kubota tractor regulator in place of the Lucas MCR2 dynamo regulator. I had purchased a Rooster Booster 6 volt positive ground ignition module, and already had my 6 volt battery and lamps, so I was determined to stay with 6 volts for the present time. I know it’s not ideal, but I knew I could make it work fine. The 6 volt scooter rectifier/regulator that I bought was quickly overwhelmed by the 14 amp capacity (and probably the open circuit voltage capability) of the stator coil, and burned out. I ended up with a commercial shunt regulator from Electrex World LTD.

I spent a lot of time on this project, but it met my goals. It looks original from the outside, it is reliable, and it was less expensive than the alternatives, as long as I don't count my massive investment of time.

Keep Shafting

Truck-Lite headlamp evaluation

I've been given a Truck-Lite model 27250C for evaluation.  It is an Light Emitting Diode -based drop in replacement for a 12 volt standard 7" headlamp with high and low beam.  Since there's only one, I've installed in in my XS650.

Initial indication is that the beam pattern is a bit strange.  The beam is strongest in a small square in the center, with a wide pattern without much vertical dispersion.  Looking into the lamp is absolutely dazzling.

This first photo is the low beam setting compared to the beam cast by the single 3 Watt Luxeon LED installed in the Sunbeam S7.  There's a big difference in intensity.  The single Luxeon is feeble in comparison.

This second photo is the high beam setting on the Truck-Lite headlamp.  (The single Luxeon was turned off in this photo).  There's not tremendous difference as captured by the camera, but in person it is a very intense light.  The brightest part is very focused, and the dispersion away from that point is rather poor giving very intense light only at that specific point.  Ride to work on Monday morning should provide the practical nature of this LED headlamp.

More later....

Voltage Regulation

... or lack of voltage regulation as the case is.  The alternator actually works too well.  I bought this cheap regulator/rectifier intended for scooters.  Its voltage stability is horrendous.  Naturally the Permanent Magnet alternator increases in voltage and frequency as I rev the S7 Deluxe engine.  The regulator should compensate for this and keep the voltage around 6.x volts and not too high such as the 7.x volts that I saw this morning.  At highway revs the ammeter was reading nearly full scale of 8 amps!  "That's WAY TOO much current", I said to myself as I sat beside the road this morning.  The voltage kept going up with the revs... its supposed to be regulated to limit the voltage so that the battery won't get overcharged.  Well, the reason I was sitting beside the road this morning was that the battery WAS being overcharged and had blown the 7.5 Amp fuse that I had installed in series with it.  I was trundling along until I dropped the revs and the alternator wouldn't produce enough voltage to keep the ignition going... at which time the bike stopped running at the intersection.

A quick disconnection of the stator leads and a jumper across the fuse, limped KYL95 back home to the workshop.

So, now I need to replace that cheap scooter regulator.  I imagine its just a simple series pass transistor regulator in there, and its not yielding good results.  The correct solution is to use a switching regulator.  Like this one:

http://www.national.com/pf/LM/LM3150.html#Overview

Oh, and I've purchased a resettable circuit breaker too.  I HATE fuses.

Awesome day!