I have this bike https://www.marinbikes.com/2012/bike_...elvio_T3_Force

It's a full cable that runs through the entire top tube. It appears to be just two holes drilled into the top tube, no guiding whatsoever. To top it off, I managed to get one of the cable housing caps in there. So now it's rattling. I tried taking off the seat post, but it looks like the seat post and top tube are completely separate. I'm wondering if I can take off the fork to gain access to the inside of the top tube, or take off the plastic inserts in the top tube that guides the cable through.

Any ideas?

ok I took off the fork, and got the housing cap out. But the hole into the top tube through the head tube is way too small to be anymore useful. Right now, I'm just trying to get the cable through, and use that to guide the housing through. It's a pain in the ass....

nevermind. I got it

For future visitors, I pent the cable with a pair of pliers, and routed it through such that the cable pointed at the hole on the other side. I routed the cable through from the rear to the front, and then routed the housing through the tail end of the cable through the top tube, pulled the cable out, and put it back in through the shifter.

Just to put in my 2 cents:
I have used a piece of thread with a knot in the end, used a vacuum cleaner to pull the thread end out the other hole. Tie the thread to the brake/shift cable and then guide the housing with the cable. I have also used this method to route bicycle computer wires through steel forks with vent holes.

I would like to think that I would have figured out that trick on my own ,but probably not. Thanks