Tuesday, August 28, 2012

CANNONBALL: PREPARING 'THE MULE'

The Mule; not afraid of dirt, although it played hell with the open cambox...
I've had my head so far inside my '28/'33 Velocette KSS/MkIV KTT hybrid, appropriately named 'The Mule', that I haven't had time to post all the photos from the magnificent Pebble Beach Week activities...patience! I thought I'd treat The Vintagent as a 'blog', for once, with a timely update on prepping an 80 year old, worn out motorcycle for a 4000 mile ride.
The Mule in 2005, on the notorious Wards Ferry Road, just outside Yosemite Nat'l Park
The Mule had sat since November 2009, when its gearbox literally split in half in front of 100 amused chopper riders, at the start of Max Schaaf's '69 Mile Ride'.  She fired up easily on the bump (no kickstarter - this is a race bike), and after a rev-rev to warm up, on engaging 1st gear the whole plot went clunk, and halted.  Due to 'massive life changes', July 2012 was my first chance to properly investigate the damage and repair The Mule, as she lives in a San Francisco warehouse, and I'd been in Paris, New York, and everywhere, as you've seen.   I wasn't expecting to ride the Velo on the Cannonball, as the engine is 1933, and I'd never found a frame number.  Dismantling the halved gearbox revealed a 1928 frame VIN, and voilá, I was no longer riding my '28 TT90 Sunbeam across the US... but The Mule still needed considerable work; a total tear-down was required.
The destroyed MAC gearbox, which objected to two gear shafts mating...

The Mule was built by Eddie Arnold, renowned Velocette restorer in SoCal, who died in 1981, and from whose estate I purchased The Mule plus garage contents (minus a MkVIII KTT, AJS K10, and other tasty restorations).   Eddie found her in the 1970s on the East Coast, where she started life, as the only Velocette KTT originally imported to the USA - to Mack Motors, who ordered only the engine, KTT 470, in 1933.  Clearly, the boys at Mack had a chassis to play with, which seems to have been a 1928 KSS, if in fact the current frame is the original Mack racing frame.  In 1933, US race tracks were all dirt, and The Mule would have been well acquainted with East Coast soil... but I have no record of her accomplishments.  Eddie Arnold decided the KTT would make a great Vintage race machine in the late 1970s, and after much development (he was the chief engineer of Mustang motorcycles in LA), she went from a mid-pack kicker to a consistent race winner.
Day 1; re-lined brakes, re-packed wheel bearings (adjustable taper rollers)
Sorting out Eddie Arnold's speed modifications required moto-forensics, and the starting point was obviously the gearbox.  Velo 4-speed gear clusters were used from 1933 to 1972 without much alteration (except the shape of the box they came in), and aren't known to 'blow up', but MAC 350cc gearboxes are fragile, as the gears are slimmer; second gear especially is known to shed teeth, which is exactly what happened with The Mule.  For whatever reason (most likely convenience), Eddie modified a MAC box to fit the KSS frame - not a huge change, but it required a bit of welding and machining of the gear case.  The MAC model was very popular in SoCal in the 50s, having won the 1953 Catalina Grand Prix under the helm of John McLaughlin; it was light, tuneable, quick, and very durable, as are all Velos.  The proper 1920s/30s 'Two Stud' Velocette KSS/KTT gearboxes were thin on the ground in LA, as Velos were never imported to the US at that time... The Mule is a singular beast.  She was part of a litter of around 80 MkIVs, so the several important parts which identify her pedigree are rare spares indeed.
Day 2: new bigend and mains, crankcases assembled
Luckily I'd amassed a lot of gearbox and other parts over the years, and had a proper '4-speed, Two Stud' KSS shell for The Mule.  The gear cluster is identical to a 1960s Venom or Thruxton, and within my warehouse lurked a small hoard of new old stock gearbox parts in their original Cosmolene (a thick waxy coating protecting machined parts for shipping and against corrosion).  So, the gearbox was at least a straightforward fix.
Day 3; the 'two stud, four speed' gearbox rebuilt and installed
Much less straightforward was the engine; I knew from letters published around 1980 in Velocette Owners Club magazines ('Fishtail West') that Eddie Arnold had heavily modified the KTT motor to arrive at the little beast's outrageous performance.  The flywheel had been lightened by 7lbs, a Manx Norton 79mm forged racing piston installed (giving a capacity bump to 400cc), the cylinder head was ported for a larger carb, and the camshaft was his own design.  That proved the most problematic part, as the camshaft lobes and rocker arms were completely worn out; nothing was standard.  I would either have to re-create Eddie's modifications, or repair his worn parts, or replace his handiwork with standard KSS/KTT items, losing the sparkling performance.  An indication of that performance can be found in John Jennings' test ride report from the Australian 'Fishtail DownUnder'. The Mule had been timed on the 2000 Moto Melée at 105mph and climbing, which is not bad for an 80 year old machine running on pump gas.  While I've had the great fortune to meet two gentlemen who'd raced MkIV KTTs at Brooklands - gaining the coveted 'Gold Stars' on them - those bikes had run on alcohol, which gives a 10% power boost, and cooler running.  The Mule is clearly a special creature.
Day 4; cylinder and head attached
Dismantling the cambox showed Eddie's thinking; he'd installed a MkVIII KTT cam (the 'K17/8' cam, introduced in 1938, whose profile is also used on the Venom and Thruxton models - it has a huge 'overlap').  But the cam form which won the 1949 World Championship wasn't good enough; Eddie separated the two lobes and re-positioned them to further lengthen the valve overlap, then added a bit of metal at the top to also increase lift.  The KSS/KTT cam is secured on its shaft by a keyway, and in splitting the lobes, the slots no longer aligned.  The tool used to create the slot inside a hole is called a broach, and these are notoriously expensive.  Eddie's workaround was simple; he brazed the lobes onto the cam-shaft...a little 'barnyard' perhaps, but it held fast from 1980 until 2009...and is still holding fast, making the whole cam setup scrap, unless I can find someone to restore the cam in situ.  He had also lengthened the arms of both rockers equally on cam and valve sides, which put pressure one side of the valve stem, causing valve guide ovality.  This mod is less easy for me to understand, and as the parts are worn, it will take some forensics, math, and graphing to sort out the valve timing he developed.

Time proved the decider on the camshaft dilemna; I'd have to 'make do' with standard parts in order to have The Mule ready in time for The Cannonball Rally.  Sad to lose The Mule's distinctive kick, she'll have to play pack-horse across the USofA; still fast, but not crazy fast.  As a speed-demon rider, I'll re-create the 'Arnold' cam system (and duplicate it; I have a bronze-head 1920s KSS special in the works), but that project will have to wait until after September 23rd, when I arrive back in San Francisco at the end of the Cannonball...
Day 4; cam and ignition timing sorted, engine complete
In the meantime, there were other issues to attend; a new bigend (easy, with help), a new clutch (easy, but getting it to work properly took 12 hours of frustrated parts swapping), new brake linings (difficult to find jobbers willing to do one-off shoes), a fresh magneto (BTH sent the wrong one, so the 1970s rebuilt item is on the bike, with the new BTH -when it arrives- as a spare), etc.  4000 miles is nothing on a new motorcycle, but it's a long way on a Vintage machine.
Day 5; looking like a motorcycle....
The Mule has a proper oiling system to its cambox atop the iron motor, but keeping the oil inside, and not all over the rider and rear tire, is difficult, as the sealing arrangements are crude. She's always been a filthy beast, and I'm trying to improve her continence.  My pal Fred Mork, vintage racer and AHRMA stalwart, rebuilt the crankshaft with a new MAC bigend from Grove Classics in England - many thanks Fred!  He'd rebuilt the crank on my '66 Velo Thruxton way back in 1989...  Hannan's cylinder head shop made new valve guides out of solid cast iron, and a new inlet valve from an HD Sportster.  You read it right - the Mule has Harley parts; let's hope there's no organ rejection.  Both Fred Mork and Hannan's supplied their work near gratis, as unasked-for sponsorship of my ride.  Motorcycle people are the best.
Ready for a few more thousand miles...

10 comments:

occhiolungo said...

great stuff Paul. For the sealing of the rockers, did you use new felt bits, or maybe try silicone goop? We fitted Kim's with brand new felt and it didn't really do much sealing at all. If you have success with other seals, I'll give them a try.

see you back here in SF pretty soon.
Pete

The Vintagent said...

Pete, I used felt, but did a trick I saw John Worthington use on his Mk1 KTT at Montlhéry in 2000 - clear silicone gooped all around the rocker slots! We'll see if that helps...The Mule has always been such an oily beast.

r50us68 said...

Are lights required?

r50us68 said...

Are lights required?

Charlie101 said...

The trick is to get sufficient dense felt, common felt fabricated today, even that I bought from a gear and bearing shop is too soft used in clothing and blankets, I found dense felt in a pair of old rubber boots winter linings and soles and I saturated it with bees wax.

Sooty said...

Bravo for bringing back such a classic machine! Safe Travels!

Don O'Reilly said...

Nice work Pablo!
Have yourself a time, but go easy on the tylenol...
Cheers,
Don

The Vintagent said...

Lights not needed in Cali; the bike is 'as per catalog', ie, it never had lights from new, and doesn't need them now. I'll attach 240lumen bicycle lights to the front and red LEDs on the rear for the Cannonball...

Hodge said...

Speaking of lights, y'all do most of your riding during daylight hours? The lights "are to be seen by others" and not for lighting the way, correct?

Great write up, thanks for starting my morning off right!

Cheers and beers
Hodge

Geokan said...

My best wishes on your cannonball run, hope you make it to the end with no problems !