Sunday, January 29, 2012

Refinishing Shimano M900 XTR cranks

In my experience (read: opinion) the Shimano M900 gruppo is one of those defining mountain bike component gruppos.  They looks amazing on nearly ever bike (92-95 of course) and most high end projects would not be the same without them. Of course I am not the only one who thinks this way and consequently these parts are very hard to find and more often then not come at a high premium for mint to NOS parts. 

Used and abused parts are not hard to find.  Probably the most abused are the cranks and rear derailleurs.  I currently find myself replete with about 10-11 M900 gruppos, ranging from beat to Mint/NOS and among all those parts I noticed that the cranks are one component I can probably restore.

As best as I can tell the cranks come from the factory with a complicated finish process.  First they appear to be forged and then the critical features were machined for precision.  Then they are clear anodized to prevent the Auminum from oxidizing. The last step is a satin finish clear coat to achieve that unique bluish/gunmetal finish M900 is known for.  The Shimano M900 is either ink stamped or applied via transfer decal just prior to clear coating.

So, here are some early pics of my first attempt at refinishing M900 cranks. I've only done some basic surface prep in the tumbler.  still a lot to do to achieve the polished finish to get it ready to anodzing.

Above - Top crank is a scratched up example with clear coat stripped / Bottom crank after 2-3 hours in tumbler (was in same condition before)

Below - Close up pics of both cranks for comparison.

So, the tumbler removed a lot of the surface imperfections.  Now I need to do some manual clean up on the end of the crank arm to remove some deeper gouges and then back into the tumbler for a higher polish finish.

A new chapter in refinishing capability

I recently acquired a used parts tumbler in an effort to improve my ability to refinish older parts. Now I just have to figure out the optimal mix of polishing media to achieve the desired results.

Wednesday, January 18, 2012

Yeti ARC repair update

Here are some pics of the repaired Yeti ARC courtesy of FTW himself!!  Wonderful work Frank, thank you very much!!

Fantastic work!!!  No wonder he is called "The" Welder!!

We're going to try and preserve the smaller frame in its original color, just touch up the faded areas, the black frame... we'll see...

Weekly refinished part

Nothing looks worse on a bike than some beat up, scratched and faded crank arms. These will complete the build package for the 1988 Fat Chance Wicked.

Tuesday, January 17, 2012

Refurbishing Bullseye crank bearings

The seals on my Bullseye cranks were shot so I finally got around to making some new ones and installing them into the bearings.

Sunday, January 8, 2012

Another in a series of refinished parts

The components on the 1988 Fat Chance Wicked were all slightly beat up and in need of some refreshing.  Here is a quick look at the refinished Magura brake levers.

The levers were fully stripped of paint, all burs were sanded down and they 3 coats of black satin chassis coat were applied to create a durable finish that will hopefully last another 20+ years.

Weekly featured part

I'm going to try (read: let's see how long I can keep this going) to have a cool or unusual part or bike featured every week.

This weeks feature is an American Breezer stem.  This part was somewhat of a surprise find on a 88/89 Klein Pinnacle I recently acquired.  The stem is probably in better shape and worth more than the entire bike it came on.

This is a very nice example of an early all Aluminum, American made stem.  The welds are thick and crude and I'm sure it would have looked as much out of place on fillet brazed steel frame as it did on the smoothly welded Klein frame.  Either way it's a very nice piece of work and just needs a little bit of refinishing to make it like new.

Fortunately I will soon have a parts tumbler and will be able to restore the stem to it's original luster.

Wednesday, January 4, 2012

1993 Yeti ARC Rescue #2

Here is another Yeti ARC complete with a cracked headtube...  No introduction necessary here, same treatment as the previous one.

Aside from the monster cracks in the front of the headtube (unlike the other one that has two crack on both sides of the bottom) this frame is in excellent condition and might skirt by with only headtube repaint.

I must say I much prefer the look of these welds to the later one, unless they only seem beefier on the older frame due to a thicker powder coat on the newer frame.

Monday, January 2, 2012

1995 Yeti ARC Rescue

Up until this point I've mainly taken on projects that maybe were missing some parts, perhaps needed some refinishing or at most needed a respray, it's time to tackle something a bit more involved.

I came across this injured Yeti ARC a couple months ago and decided I wanted to try and give it a second chance. Like many of the early to mid 90s ARC which have either a cracked headtube or a cracked seatpost binder bolt, this one suffers from the former (both sides of headtube cracked) and in most cases would be considered a lost cause.

This specific ARC (A19xx) is most likely a late 94 or 95 production model and therefore definitely worth saving. Aside from the cracked headtube the bike is in very good shape with no other visible damage anywhere else. The bike came with a host of period correct Ringle and Grafton goodies that will be refinished and reused later on during the final build. I haven't decided on a color for this and will be asking for input for the readers on which way to go with it.

This ARC along with another one with a similar ailment are flying off to FTW for headtube replacement in the next couple days. I think this one will get a full respray while the other one (an earlier 92/93) which is in better condition can hopefully be kept as original as possible, maybe only require the headtube to be repainted.

Stay tuned for a progress updates on these two rescues!!

1995 Klein Attitude Team Storm - Update #3

Well, Happy New Year everyone, hope you all enjoyed your holidays and are off to a great start this year.

Here is a another quick update on the 1995 Klein Attitude Storm restoration project.  The frame, fork and MC2 are painted and will be arriving stateside in couple weeks for assembly.

Since the last update the frame received a complete set of decals and several more coats of clear.  All that remains now is to build it up!!