Attaching a fender to a Yamaha YBR 125

[Sam250]

Whilst driving to nowhere in particular today I heard an irregular squeaking/screeching from the front of my bike. I had a look and found my fender was attached by only one screw. What happened to the other three I can only guess. I was 15 minutes from home but had no easy way of detaching the fender and no easy way of carrying it if I did, I decided to just ride home and hope for the best. Five minutes later I the screeching became constant and loud but before I had a chance to pull over the fender had come off the bike and was lying in the road. Some considerable swearing later and the fender is left at a nearby pub whilst I went home to get a bag.

Whilst I'm out retrieving the thing, perhaps you can help me in getting it back where it should be. How do I find out what type of screw I need? I can't see anything in the Yamaha service manual. There don't seem to be any broken bit of screw left in the screw holes in the frame of the bike, but I'm not sure if the internal screw threads are damaged. Any advice appreciated.

[mealexme]

Do you have a tape measure?

I believe Yamaha use the metric system, which means you will need to look for bolts with an M before their name.

The way you work it out is in mm, so if you have a 5mm hole and the bolt needs to be 8mm long, you are looking for an M5x8 bolt

[Paul-Kent]

Sam,

It may help if you put your location in your profile. Someone nearby may be able to help you out.

Personally, I'd guestimate at M6 x 10

[skiffer]

Something falling off a bike is the worst... my exhaust fell off. Worst day!

[Sam250]

Thanks all. I'll do some measuring when it's light tomorrow. Does thread spacing come into it? I'm not very knowledgeable when it comes to hardware and mechanics, but I want to make sure I get the right bits and attach it so it won't fall of again!

There's a pretty big crack across the fender. I'm thinking plastic cement will sort that.

 

It may help if you put your location in your profile.

 

Good idea, done.

[mealexme]

Does thread spacing come into it?

if, by thread spacing you mean the distance between the peaks of the thread itself, then all M bolts are the same, so every all M5 bolts will have the same distance, all M6 will be the same etc

 

There's a pretty big crack across the fender. I'm thinking plastic cement will sort that.

 

It depends how you define "sort".

It should glue it back together, but unfortunately you will be able to see the crack fairly obviously, but at least it wont be falling off anymore.

The only way to get rid of the crack is to either buy a new one, or spend a lot of time sanding out the high spots, filling the low spots, sanding down the high spots again etc until it is all the correct level and re-painting the fender

Personally, I would leave the crack in there. 125's are expected to have a bit of fairing damage. It shouldn't effect the resale value and depending on where it is, it might not even be noticeable when its back on the bike

[Sam250]

Thanks again for your help, all. It's sorted now. I used liquid plastic weld to hold the crack together. The crack was across enough of the width to worry me it might slip in two when riding on a bumpy road. It is on the back end of the fender but is visible, and the weld leaves ugly black melted plastic along the crack, but seeing as the fender isn't even the same shade of red as the rest of the bike I can ignore these cosmetic flaws. One day when I want something to do maybe I'll get some sandpaper, filler and the right shade of paint and do my best on it.

As for fixture, I went for M6x25 wide head hex bolts and they seem to have done the job perfectly. I wasn't sure if it was M6 or M5 so I bought a small pack of each and M5 was too small. They have wide heads, and the holes on the fender are quite large compared to the screw width in the frame and I didn't want screw heads too small to cover those holes, if that makes sense. Around the front wheel is an awkward place to get tools in so it's tedious work making fractions of a turn at a time with a small spanner. I don't know if cross-head screws would have done the job fine and been easier to get on, but I imagine you can't tighten them as well and I sure don't want this thing coming off again!