Hello DB
I had to work on mine. But it was my fault. It was a simple cable break and I didn’t care at the time. I just need to get done. That said…are you meaning the small pin that interlocks with the sprocket like feature just comes out…?…and then …much to your surprise…your front tire is now on “swivel”…?
If so…is the pin that interlocks too short…?…or is the spring that holds it in tightly, too weak?
My only thought is that my 5 or 6 year old 3900 has “certain parts” on it…but…your “couple year old” 3900 may have different parts on it…to save the MFG cash in production.
The only way to check would be to see a pin on a parts list…or see if the current pin is all the way engaged into the “cutout” on the sprocket like feature. If it’s not bottoming out…it may be the pin length, mating sprocket cutout or the wrong spring to push it hard into the cutout and also hold it there.
Let me know. I hope those suggestions are simple to check and / or cheaper and easier to fix.
Again…let me know…good luck.
Last…when I finally replaced my cable, It seemed I had to adjust it. I wonder if the cable is tight and won’t let the pin “bottom out” into the sprocket.
( Although…that phenomenon happening on two machines seems unlikely. )
I’d check the spring to see if it’s too short or weak. I would imagine it should not be loose or ineffective when the pin is engaged. It should still have length and holding power.
( I hope that makes sense. )
Maybe…they changed the pin length and did not see this coming.
( But, that means a nationwide complaint too. )
Maybe the female sprocket cutout is partially blocked…?…that seems unlikely on two machines too.
I’d still check those things first.
I hope I helped.
Dan
