K2 4000 Swing arm questions.

[digimancer]

Hey guys, new to the forum, will add pics and info later. I have an 857 that I have had since I was a teenager, around '98 and an 856 that I got about a month ago. Love em both... But this isn't about them... Its about the K2 4000 I picked up on Craigslist Monday for $200...

This forum seems to be the Proflex sanctuary, so I thought I'd ask some opinions about it and hopefully be safe from trolls..

The bike looked pretty good in the pic on CL, and when I got to the guys house it looked pretty muddy and greasy, which led me to believe it was well used, and poorly maintained... Today I finally got around to examining it closely. I powerwashed the living hell out of it and found that the rear swing arm looks pretty terrible now that I can actually see it... Many surface scratches (obviously it was well riden)

It looks like for some off reason, the guy or someone epoxied cable guides onto it and then sealed up the hole for the cable guide for the rear derailleur... On top of that, it looks like the outer layer of plastic/resin is starting to separate from the carbon actual fiber... This worries me greatly as damaged CF is TERRIFYING to me (I'm a 200lb guy)... So my question is, how worried should I be? Anyone have a clean replacement to sell? Is there an Aluminum alternative?

Additionally, the original front forks are also CF but look to be in better condition, some surface scuffs, but no real apparent damage.. I'll try to get some pictures of it up tomorrow, as well as my mini Proflex collection. On a side note, I think I will be selling the 856 if I can get this K2 4000 straightened out, the 856 is in pretty good condition comparatively. Really with I could rob its rear swing arm!

[Willie_B]

$200 is good deal if you will be able to use it. I was just saw an article in Dirt Rag about places that repair carbor fiber frames. They make it sound like the frames are better than thought and can be repaired and used without problem.

Welcome to the group and good luck with the cleaning and check out.

[Colin]

the internal cable routing relies on a tube for the cable to travel down and if this came loose then it's pig of a job to run the cable through, so maybe this was why it was rerouted.
I've seen some very minimal surface de-lamination on the swing arms but hopefully this is just the outer lacquer coat and not structural, or maybe it's worse than this?
A lot is made of Carbon failure fear, but hey why is an aly weld break any better?
Not many  carbon swing arms come up on their own for sale, I can't recall seeing one for ages.
Yes, there is an aly alternative, as fitted to these models:  Evo 2.0 & 3.0's; 900, 1000; Disco Monkey; Flying Monkey.

Or you could even take the swing arm and stay and shock off of your 857 and fit them to the 4000 as I believe it's a direct swap.

Col.

[digimancer]

$200 is good deal if you will be able to use it. I was just saw an article in Dirt Rag about places that repair carbor fiber frames. They make it sound like the frames are better than thought and can be repaired and used without problem.

Welcome to the group and good luck with the cleaning and check out.

The guy who makes bamboo frames does carbon repair http://www.calfeedesign.com/repair/ but I'm pretty sure it would cost a small fortune.

[digimancer]

Or you could even take the swing arm and stay and shock off of your 857 and fit them to the 4000 as I believe it's a direct swap.

Col.

Hrm... Brilliant, but I love my 857, it is def my A-Bike of the three, Do you think the 856 swing arm would work?

[digimancer]

^CF Images
Is it just me or is there a plastic housing over the CF?

[w2zero]

Yep, there is a thick clear coat over the CF. 

[Colin]

... Do you think the 856 swing arm would work?

Definitely Not

I reckon that swing arm looks fine, note I said "looks" as I'm judging it from photos.

unless there is very serious de-lamination or cracks or deep gouges into it, I would think it will be fine.

I'm a not a CF expert, but bear in mind that the CF is just "strands" or a thin "sheet" embedded into (in this case) thermo plastic, to strengthen the structure, in itself it doesn't have much rigidity, so unless the thermo plastic is seriously damaged, it should be OK. I think they then top coat the structure with a lacquer which may detach itself in places over time.

I think we have some members on here that have much more "hands-on" experience of CF than me, so they may choose to comment?

That cable rerouting is a right bodge up, amazing how ugly some people will make their bikes!

Get out there and ride it!

Col.