I have in the past busted Dahon's chops for a problem with my Mu P8 which was the first folding bike I ever owned. I had problems with the hinge.
Before I can start telling this story I first have to say I have lied somewhat. I have stated several times in the past that I "got rid" of the Mu P8. That in some sense was kinda true. I drug it off somewhere to another building I store stuff at and never got around to disposing of it. I had planned on field stripping it for parts. In fact I was hoping someone would steal it as it was somewhat accessible to anyone in this particular building.
The only reason I ever said I got rid of it was to spare myself embarrassment for this whole problem and it alleviates having to answer any questions. So, here's the story:
I bought the Mu P8 from a local sporting goods store here in Okinawa called Sports Depo. Almost immediately I had trouble with the hinge area. I took it back to Sports Depo where they said they'd have it a week and they had it two. They called me after two weeks to pick up and when I got there nothing had been fixed.
They told me they had the frame hinge parts but no instructions and that they'd have to contact Dahon for the instructions and it would likely be another month or so.
So I had a fit and told them to give me the parts and I'd fix it myself.
Basically I did, and it was real easy but it didn't solve the problem. I surmised the frame was bent and sought out Dahon and a local LBS where I did not buy the bike for help. And now I've changed the hinge parts and the shop I bought it at told me if I did I was on my own.
Essentially no one would help. (Also the handlebar stem was bent and it still is).
So anyway I'm preparing to move and it's a quiet day at work and I decide to retrieve the Mu P8.
The main reason was that I bought a used Park Tool PCS-11 work stand today and I wanted to test it out.
So I mount the bike and I start taking everything off and I'm freaking SHOCKED. Nothing is tight. NOTHING. Bottom bracket is loose, front stem is loose. I'll bet you lunch the bike was assembled by teenagers at the department store. I'm surprised this bike never killed me.
Anyway I get to the hinge area and I decide to look it over once more just for the heck of it because the bike it light and accessible with everything off of it.
So I pull the hinge back and I notice that it semi releases as it should.
When the lever gets more than halfway in it's travel it starts to tighten back up again!!!!!!!
So I have the old parts and I look at the cam (I guess that's what it is). It has an offset hole in it and I start thinking
OH MY GOD I wonder if I put it in upside down?
So I disassemble the hinge and flip the cam and guess what? It works like a champ. The frame is not bent.
So then I work the hinge like 400 x's to see if it's going to go bad or not. It's perfect.
So my probably initially was that whoever assembled the bike did me no favors. I still got no love from Dahon other than they sent repair parts to the store where I bought it.
So I began to build the bike back up and I carefully cleaned, greased, and torqued everything like it's supposed to be.
I got the derailleur set up perfectly but I've decided to get new brake cables so I'm still down. Also that handlebar stem is still bent and needs to be fixed. If I can get my hands on another one I'll sell the bike.
So anyway I do want to apologize to Dahon. Their initial hinge mechanism did fail, no doubt as all the parts were worn with elongated holes. Again I'll bet you the assembly had something to do with this.
But I screwed the pooch with the cam installation. Otherwise it would have been fine all this time.
I'll cross post this at Dahon as well.