Stripped Bars When Riding MB

[MonsterEnergy]

So today I was riding my MB around town and the bars came loose. It's an HF 79cc 4-stroke, stock, on an Electra Cruiser bicycle. Does about 39mph on the flat and I've had it up to 46mph down a steep hill. Not sure what the gearing is, but it's pretty tall, as the acceleration isn't good but the top end's fine. There are pictures of what happened to the bars attached, but essentially the threads on the bars stripped and the bars were left to move freely in the headset. I had to ride home with my bars moving 360 degrees which was less than ideal but doable if you had to. The bike's unrideable until I get the bars fixed, but I've been thinking about shorter, straighter bars or even clip-ons, and this just gives me an excuse to do it. I've got a 212cc bike in the works, but I need something I can ride until that's done so I gotta fix this bike.

My guess as to what happened is that I went over a speed bump a little too fast while holding onto the bars and it put enough pressure on the bars to strip the threads then and there. That coupled with the wear over time from the engine's vibration probably did it. If this has happened to you, let me know, because having this happen while I was riding wasn't a good experience.

Update: I took a look at it and even with the screw on the headset that puts pressure on the bars and keeps them from moving fully tightened, they still had play. I took JB weld and put it on the threads and got it back together and I think it's good to go. I'll probably figure something out on my next bike to keep this from happening.

 

[MEASURE TWICE]

You mention stripped, but I ask have you tried loosening the screw(s), probably hex key head, then re-centering the handle bar, then re-tightening?

If the screw or screws are stripped and keep turning in either loosening or tightening then Helicoil, thread insert, or replacing the stem could be needed. If the thread do loosen and tighten and you can tell it clamps down but would not stay put, be sure handle bars are centered.

The picture shows what I think as they are not centered. The knurled part should just slightly be visible on each side of the clamp. Not the amount in the picture. The bar does narrow slightly from the area on each side of the knurled center spot. The amount the clamp can squeeze is limited and without the bars being centered that may be what is preventing the handle bars from moving.

I have a bmx type stem clamp with four hex head screws which are more rugged. If you have to get a new stem you might consider that type. I bought a used part at some savings and it works fine.

 

[MonsterEnergy]

You mention stripped, but I ask have you tried loosening the screw(s), probably hex key head, then re-centering the handle bar, then re-tightening?

If the screw or screws are stripped and keep turning in either loosening or tightening then Helicoil, thread insert, or replacing the stem could be needed. If the thread do loosen and tighten and you can tell it clamps down but would not stay put, be sure handle bars are centered.

The picture shows what I think as they are not centered. The knurled part should just slightly be visible on each side of the clamp. Not the amount in the picture. The bar does narrow slightly from the area on each side of the knurled center spot. The amount the clamp can squeeze is limited and without the bars being centered that may be all that is necessary.

Yeah, the bars were off center because I had to pull them out to see if the locking threads (not really threads, but I'm not sure what else to call them) were stripped or if the screws just came loose. That was just a picture showing the state the "threads" were in. I got it back to its regular condition and tightened the screws but there was still a bit of play, so I put JB weld onto the "threads" and put everything back together, tightening the screws as much as I could. I just went for a short ride on it and it's fine. Maybe the screws weren't all the way tight when I bought the bike and that's why it shook enough to damage the "threads," and effectively strip the locking threads on the bar. Not totally sure. The hex head screws themselves aren't stripped or anything; if that were the case, I would have a bigger problem. What I did oughta hold. Thanks for the advice though, love how happy to help people on this forum are! Happy riding!