Resurrection of a Prophet

ovim

Dirt Disciple
A long time lurker here. I've really enjoyed reading the project build threads here and since this falls in the somewhat retroish category I thought I'd show you my "new" Cannondale. I'm sorry I don't have much pics of the work in progress so this will be just text and a pic of the finished bike.

About a year ago I noticed the significant price drop of quality second-hand 26" bikes due the advent of the new big wheeled mtbs. My other mtb is a Inbred 29 and I had been thinking about getting a full-suspension bike for a while but since my riding is so sporadic due to family etc I couldn't justify another new bike. Oh and I also didn't (and still don't)have  the money... So I started to combing the local forums for a suitable bike.

After a few weeks of searching I spotted this 2005 Cannondale Prophet 600 for sale and after a brief e-mail exchange with the seller I had learned that there was some (what the seller described as) damping problems with the front fork (do you call a lefty a fork?) but otherwise the bike was in rideable condition. So after some negotiaition with the seller we agreed on the price of 400eur including shipping.

After a few days I received the bike and I could tell from the rusted bolt heads and the overall rough feel that the bike hadn't seen much tlc for quite some time and apparently it also had been sitting outside. I started taking the bike apart and although the bike had sort of matched the sellers description I discovered some problems as I proceeded.

The things that were good:
Frame was solid and straight with some scratches and cable rub marks but it needed new pivot bearings. Headset and lefty front hub were okay and needed just some new grease. Rims were straight and true, as good as new really, and also the Onza tires were good. The Manitou Swinger 4way shock was holding air and the rebound adjustment worked, but I thought it was due for a service since I suspected it had gone a very long time without one. Stem and seatpost needed some new screws (rust) but were otherwise ok. The derailleurs and shifters were in useable condition but i ended up replacing them later on.

The bad:
The 140mm Lefty Max FFD had severe issues. The rubber boot covering the "stanchion"/bearing races had a cut in it which had let water in and resulted in severe corrosion in the needle bearings and bearing races. Also the damping oil had leaked and due to that the front brake pads were dead. Also the rebound adjustment rod inside the fork was stuck because of corrosion.

Rear hub (Cannondale Omega) had some wear/pitting to the bearings and cones but the cups were still ok.

The Truvativ Gigapipe Isis bottom bracket was gone and Hayes HFX-9 rear brake had a lot of air in the system and no power. Both of these were replaced by newer/better parts later on.

So I started looking for parts and instructions especially for servicing the front and rear shocks. But I started the rebuild with the frame. After thoroughly cleaning the frame I touched up the scuffs and scratches on it with Humbrol enamel paint. The color is not an exact match but it's quite close. You have to really look for it to see it. I also replaced the pivot bearings (quick job on a single pivot frame).

Then I started tinkering with the front fork. For those who don't know:  "stanchion" on a Lefty is actually a square alu tube with steel bearing races on each side. When the suspension works this inner tube slides inside another alu (outer)tube with a rectangular inner profile and steel races on the inner faces. There's four strips of needle bearings between the four faces/races on inner and outer tubes. All these parts can be replaced but the bearing races come in different thicknesses (differences are like 0.1mm) and on one fork there's usually at least two thicknesses from the factory. The different thickness races are used to counter variations in manufacturing tolerances. So that the telescopic action is smooth, and with as little resistance as possible but still without play in the mechanism.

Luckily all the parts for the Lefty were available and after some trial and error I managed to order the right thickness steel bearing races. It's surprisingly difficult to measure the thickness of the races and the first batch I ordered were too thin which resulted in play in the fork. Putting the fork back together with the races and bearing strips is quite difficult but it gets easier if you do it enough times :). Changing the oil and seals and getting the rebound adjuster to work wasn't very hard with the service manual at hand.

Servicing the Swinger 4way air shock was another difficult job. I had some problems getting it completely apart, but finally managed to do it with some help from a friend after many many attempts. After changing the seals another tricky part was getting the shock back together. The reassembly had to be done while the whole thing was submerged in suspension oil to keep any air out from the damping /internal floating piston.
I also changed the mounting hardware (bushings etc) and installed the shock back on the frame.

Since I couldn't find spareparts for the rear hub I decided to try repair the cone races with a trick I saw somewhere on the net. I sort of lathed the wearmarks/pitting off the bearing races with an electric drill. First I threaded the cone to an old axle. Then I tightened it against a locknut and attached the axle to a drill and used a file to lathe the worn out surface off the race while the drill rotated the axle+cone. Then I used sandpapers of varying roughness to polish the "new" surface with drill still running. This was a surprisingly quick job, and the cones came out looking like new. I don't know how long they'll last but after loading the cups with grease and new ball bearings the hub was rolling smooth once again.

Then it was time to start putting the bike together. I had collected almost all the parts (some used, some new) while the project was on hold (sometimes for weeks) while I was scratching my head because of the fork or the rear shock or both.

Specs (for now)
Original wheels. Cannondale hubs laced to Mavic XM117 rims with DT Champion spokes.

FSA FR-270 seatpost and scruffy Fizik Nisene saddle that came with bike (for now)

Onza Canis 26*2.25 tyres

SLX M660 HT2 crankset+bb with Absolute Black 32t narrow-wide chainring.

XLC red nylon? pedals

SLX 11-36t cassette and KMC 10.93 chain

M786 Deore XT Shadow+ rear mech with XT Shifter

Hope Mono Mini (2004) brakes I got for almost nothing from a guy who thinking about throwing them away!?!

Original Cannondale Stem and new wide Funn FullOn handlebar.

The suspension still needs some fine tuning but it's a great ride already!

Possible future: I've read that people ride these frames with 650b wheels....

Sorry about the lengthy post, but if you read it this far here's finally a pic of the bike as it is now:
24461607034_a828c3ffbe_b.jpg
 
Excellent job, looks similar to the same era Marin Mount Vision etc (apart from the fork.) Keep an eye on that rear hub. You may have removed a hardened surface from the cones on which the ball bearings run.
 
Thanks for your comments! I felt rather stupid after hitting the submit button and seeing how long my first post had become. I quess I got a little carried away with my story..

JackN":2ozizonw said:
Excellent job, looks similar to the same era Marin Mount Vision etc (apart from the fork.) Keep an eye on that rear hub. You may have removed a hardened surface from the cones on which the ball bearings run.

I had to look up that Mount Vision and indeed they're similar. I read about that bearing race surface thing too but since the hub isn't that special I'm not too worried.
 
Great job, I love a good full bike refurb. Nothing like the feel of a new bike with everything running smooth and you know you've done the spannering yourself.
 
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