An edited and illustrated version of the following appeared in the August 2018 issue of the Ariel Owners Motor Cycle Club (AOMCC) magazine Cheval de Fer
. For anyone coming to this thread for the first time it serves as a ~1500-word "Executive Summary" of what follows in the 1400+ posts that currently total the equivalent of 250+ single-spaced pages of text."Executive Summary" of this ThreadBackground
At the time of this writing in early July 2018 the start of the two-week, 3750-mile, cross-U.S. Cannonball ride is less than two months away. Eighteen months ago I was one of approximately 110 people from a large pool of applicants who were informed they had succeeded in obtaining entries for this event, which is for machines built prior to 1929. However, that posed an immediate problem since I didn't own a machine old enough to qualify.
Harleys and Indians are a dime a dozen in the U.S. (well, more like $30k+, but still relatively common), so they make up the bulk of the entries. However, I've ridden British bikes "forever" so I wanted one of them, if for no other reason than to be on something different. Making a long story short, after three months of following dead-end leads, a 1928 Model C Ariel that was collecting dust at a friend's house in Dublin revealed itself and soon was on an airplane headed to me.
I've never had an Ariel before, but it has a special appeal because it was designed by Val Page and I have three of his later BSA Gold Stars and even have written a book about these machines. Although the dealer sold the Ariel to my friend as having been restored, and externally it was in great condition, I fully expected I would have to rebuild it myself, which is what I spent the next year doing. In the course of this I found that although some of the mechanical work had been done correctly, there were so many bodges that the bike would have failed within a few hundred miles. So, over the past year I've restored the bike down to the last nut and bolt.Starting the Rebuild
The first problem I faced in the rebuild was there appeared to be essentially no technical information on this machine. But, I slowly started collecting photocopies of whatever little I could find and, starting from nothing, my "shop manual
" has grown into two binders holding nearly 700 pages and with tabs separating the material into appropriate sections. Also, I measured every piece that came off the bike to create a 'General Data' section that's now 8 pages long. In hot rodding terms I "blueprinted" the Ariel, but in many cases that required first figuring out what the original specifications would have been.
My original plan was to ride the bike for a while before rebuilding it but before I realized what was happening it somehow found itself on the lift with enough parts removed that the restoration was underway. Here I'll only touch on some of the highlights, but my rebuild is extensively documented on the web in the equivalent of over 250 single-spaced pages. Search for the words Britbike and 1928 Ariel to find it.
The first "major" task I undertook was to fabricate brackets for a headlamp, which has an unusual mount consisting of tapered lugs on the forks. For this I machined a die from a large block of Al and used it with my 30T press to form stainless tube into the necessary 'S' shape, brazed them to tapered end pieces I had made to fit the lugs, and pressed flats into the end with a form to give a curve where the flat portion meets the rounded tube. The forks then came apart so I could Magnaflux them and do repair work on the spindles and bushes. The steering damper assembly was a rusty mess that didn't fit so it took some machining to set things right. I turned both drums on the mill, which were a fair bit out of round, and new high performance brake linings are properly arced to the measured IDs of both.The Engine
With the forks and wheels taken care of it was time for the engine. Thanks to finding two people who had original pistons and rings to weigh I was able to calculate the factory's original balance factor which I then used with a new Omega piston. I machined a torque
plate for the cylinder, which my measurements showed made a significant difference, and then used it while boring and honing the cylinder for the +0.060" piston. I machined and honed the valve guides from G2 Gray Iron and made a new timing-side bush from phosphor bronze for the crankshaft and line-bored it on the mill. In case it's not already obvious, considerable precision machining was needed to restore this "restored" motorcycle.
The recess in the case for the drive-side bearing was oval so I took off enough material to make it round and then plated Cu on the new bearing to give it the necessary press fit. The pushrods were in bad shape so I made a set of new ones using CrMo tubing along with welding and grinding Stellite to shape for the ends. The connecting rod was slightly bent so it took two jigs and several trips back and forth between the press and surface plate to get the small end accurately parallel with the crankshaft.
Although the cam faces themselves were fine, both ends of the camshaft were in bad shape so I masked most of the component, plated the ends with hard chrome, and then used a tool post grinder to remove the excess. I then made bushes from phosphor bronze of appropriate ID to match. I took the time to machine a "universal" crankshaft assembly jig for pressing the two halves of a singles crankshaft together in close alignment (to minimize the need for adjustment) since such a jig would be useful for other rebuilds in the future. I also very accurately aligned the crankshaft axis on the milling machine and faced the crankcase mouth parallel to it.
Turning to the head, measurements showed significant distortion of the valve seats when the head was torqued so I used the torque
plate with a cylindrical spacer against the sealing surface when cutting the seats for new valves. I used Neway cutters and did 4-angle jobs on both seats. The faces of the rockers were in bad shape so I made a jig to rotate them at the correct radius and used the toolpost grinder to recondition them.Gearbox Issues
Once the engine was assembled and back in the frame it was time for the gearbox. It is stamped 'QL' so when I saw an advertisement in the December 2017 Cheval de Fer for new QH gear sets I immediately ordered a set. Unfortunately for me, when I finally got to the point of opening the gearbox I found it already had QH gears in it. Oh well. The main issue with the gearbox was the open-ended bush at one end of the layshaft was enlarged so grease and oil would have easily oozed out so I made a blind bush to replace it. I also made a spacer/baffle from Teflon for a gear on the mainshaft in the hopes it would slow oil exiting via that route into the kickstarter housing.
With the gearbox back together attaching the drive gear proved more work than it should have. Aftermarket gears are flat, rather than with the necessary spacer/hub as part of them. Although that is easy to solve by machining a separate spacer, I discovered that aftermarket gears are broached incorrectly and don't fit on the splines, forcing me to spend time with a file to hand fit the sprocket to the gearbox.Final Assembly
Once the gears were sorted out and the bike reassembled, which requires dealing with a myriad of associated details, it was time to start it. It started and ran great, except for the oiling system. Making another long story short, the plunger of the oil pump had excessive clearance so I rebuilt it with a new plunger I fabricated from W1 tool steel and with necessary clearances obtained with Sunnen internal and external hones. I also needed to wind my own replacement spring since the spacing between the plunger and housing doesn't allow for any standard spring I could find.
As of this writing the last task is to completely rebuild the magneto. The magneto is working now so I'm using it on shakedown runs, but shortly will temporarily swap it for a rebuilt magdyno so I can continue those runs while working on the magneto. Before the middle of August the Ariel along with necessary tools, spares, and supplies has to be crated and on its way to Portland, Maine for the initial events starting September 4 so the clock is ticking.Final Note
Like many (most? all?) commercial restorations, the Ariel's beauty was only skin deep when I got it. However, thousands of dollars and countless hours later, this "restored" Ariel now actually is restored. Stay tuned to find out if it has a trouble-free ride across the U.S. in September, or if I overlooked something critical.
This forum has very low activity so starting this thread represents true optimism.
A 1928 500cc Ariel Model C is on its way to me to ride in the 2018 Cannonball which takes place in ~17 months. Although the bike is complete and "restored," all too often restorations are only skin deep so I will completely rebuild it myself. In preparing to do this I've assembled my own ~250-page "shop manual
" by gathering and organizing technical information from a wide variety of sources (e.g. D. Barkshire's Black Ariels
, G.S. Davison's The Book of the Ariel
, the Owners' Guide
, Burman manuals
, the relevant posts on the Ariel owners' club forum, etc.).
With the above as brief background, and after having gone through all the information I could find, I am left with a number of questions. In no particular order, what is:
-- the balance factor?
-- the connecting rod length?
-- the free length and diameter of the valve springs?
-- the head diameter, stem diameter, and length of the inlet and exhaust valves?
-- the carburetor size (i.e. ID of the inlet tract)?
-- a modern spark plug for this bike?
-- the number of teeth on the rear sprocket?
-- a modern grease to use in the gearbox?
-- a modern equivalent for "Crimsangere" grease?
-- the diameter and number of steering head balls?
Of course, I'll be able to answer many of these questions for myself once the bike arrives and is in pieces. However, I plan to ride it for a while to learn its idiosyncrasies before disassembling it, and the 17 months will pass quickly, so I'd like to get as much of a head start on this as I can.