Yamaha WR250R and WR250X Forum

Grassroots · Veteran Member

Broken chain causes carnage!

tomasn · Member

what broken on chain? master link? with clip or riveted? I vote for good epoxy glue, be cause welding operation can deform thin wall of case.

Grassroots · Veteran Member

Master link broke, clip link not riveted.

Thanks for the vote on epoxy glue. JB weld is a type of very strong epoxy. I think that you're absolutely right and that an actual metal weld would certainly damage the thin wall of the case, along with melting down anything plastic and rubber nearby too.

Thanks for your input Tomasn.

Paul.

Grassroots · Veteran Member

So having just spent half an hour putting everything back together, i'm extremely pleased with the out come of JB weld in respect of how it looks....

20170129_123028[1].jpg

I shall just have to wait and see as to how well the JB weld it holds up. I think i'll give it a couple of days just to be sure that it's set, as it is still quite cold outside. Fingers crossed by next weekend i'll be back out on the trails and this little episode will become a distant memory smile .

Enjoy the rest of the weekend one and all.

Happy riding,

Paul.

Brian · Admin

Really sorry to hear about the damage Paul. It is unfair that it should happen to someone like you who is so fastidious in the care and maintenance of his WRR cry

The repair looks good but, God forbid, if it doesn't hold, what if you were to drill the hole through into the casing using a slightly smaller drill diameter to allow you to tap a thread in the casing and put an Allen-headed bolt through?

Brian

tomasn · Member

Mine first mind was like Brians, but what if the story will repeated in feature? Hole in the engine case.

Brian · Admin

tomasn wrote:
Mine first mind was like Brians, but what if the story will repeated in feature? Hole in the engine case.

Very good point - I hadn't thought that through disbelief

jono · Member

Hi Mate Im sorry to see the damage to your bike. I have used JB weld for years and it always works for me, as you say give it a a long week to go off.

Grassroots · Veteran Member

Thank so very much for such kind words and thoughtful input guys .

...ha ha. Great minds think alike. Chatting with a buddy of mine, he suggested the drill and tap idea and we came to the same conclusion smile . He also reassured me that he too has used JB weld a lot over the years with great success.

Fingers crossed and here's to having some self control for once and not going back to meddle with it for a few days, before it's had time to truly set biggrin

Paul.

SteveT · Veteran Member

Well Paul, that's quite a coincidence. That self same casting has broken on my bike too on a rideout last weekend. It wasn't through a broken chain though I don't think. More on that in a minute.

I was riding up a rocky climb, and found I couldn't change gear. The lever wasn't returning to neutral position to allow engagement of the next gear. ****, I thought. Gearbox return spring broken. Engine out and a full strip down to replace it as it's inside the gearbox.

On inspection is was relieved to find that it was "only" the bottom case saver retaining bolt casting that had broken. Exactly as yours, Sandman case saver, same bolt, same casting. Mine had bent across and was fouling the gear lever pinch bolt, prevent it having proper movement.

So a roadside fix to remove the bottom bolt, broken casting and the Sandman outer part allowed me to refix the case saver part with it's 2 bolts.

At home on closer inspection I could see that this was not all a "new" break. Of the broken surface about 80% was dirty and had been broken or fractured for a while. The remaining 20% had finally given up on the rideout and allowed it to fail.

So, I think to myself, when did the original 80% damage occur. I really don't know. But your post has got me thinking. Last year in France my chain broke (at the split link joint). The chain didn't wrap itself around like yours, but laid out on the ground behind the bike, just like a snake. But just maybe it caused the damage on the way out.

I'll never know for sure. Also, I was puzzling about how to repair it. I had the same concerns about heat damage through welding, and burn through of what are probably very thin castings.

I was considering an Araldite repair. So, JB weld. Is it better than Araldite. Is it the same thing under a different name. I'm heartened to hear all the positive comments about it. I can now see a successful repair ahead.

Grassroots · Veteran Member

Ahhh Steve! I'm so sorry to hear that you're in the same boat! Or bike as the case is biggrin . I guess now that this really does happen to the best of us and not just me.

Having shockingly some how found the the patience to leave my repair well alone for an entire week, today i got round to checking things out and buttoning her back up. I am over the moon to be able to say that not only does the repair look extremely pleasing to the eye, but it has in fact actually held up! I applied a fair bit of pressure on the casting and attempted to give it a real good wiggle... Rock solid, it stayed put. Okay, so lets see how it stays put once i gently tighten the new bolts into place... deep joy, all is well smile .

I will very much keep an eye on how things go over the coming weeks and hope that it doesn't break free.

As to your incident... What i could see when putting everything back together, is that should a chain break, the chain itself will almost certainly whip back right at the tip end of the casting. The Sandman will very much protect the engine casing, but the casting will always be vulnerable to damage bleh . I can only imagine that although you were lucky in your chain snaking off behind you, your casting probably did actually take a good old hit causing a fracture.

I've not used Araldite before. From a little research i can see there are many different products from these guys and can only assume that in essence, the right product will be just the same as JB weld. I chose JB because it is supposed to take huge pressures and is resistant to high temperatures, along with the fact that it was already to hand in my work shop biggrin .

It would appear that most chain breaks happen at the point of the master link and that most of us seem to use split links. As a preventative measure for the future, I'm thinking of using a rivet link to replace the master clip link. I will then carry a master split link with me in a tool roll for when out and about to make a potential short term repair should the chain ever break again.

I hope some of my repair luck makes it's way over to you Steve.

Very best wishes to you,

Paul smile .

Grassroots · Veteran Member

...Okay so having ridden once, i found the chain stretched considerably with the new temporary split link. Having re set the wheel again to tighten the slack, i needed to remove the Sandman to get at the space behind it....surprise surprise, the damn casting drops out in my hands again cry .

I can see very little JB weld on the end of the casting or the point at which it broke despite feeling i'd previously given it a good coating. The casting fits back perfectly and marries up very well. Guess i now have one of three options available to me...

1. JB weld it again with a little more this time.

2. Try a different epoxy such as something from Araldite as previously mentioned by Steve...not sure which product from them specifically as they seem to sell a few.

3. Launch the casting over road and run the Sandman with only 2 bolts in? ...Doing this might cause damage to the gear shifter should the chain break and whip back again in the future?

Any thoughts most welcome smile

Paul.

SteveT · Veteran Member

Look on the bright side Paul. You are the crash test dummy so that I can get mine right!

I haven't "glued" it yet, cos it's been too cold. I had the idea of running on 2 bolts too. I'm not sure what to do now. I suppose a glue attempt has got nothing to lose. If it breaks I can go to 2 bolts only. Anyway, I'll wait til the weather improves.

Grassroots · Veteran Member

Ran just the 2 bolts up until now which was fine as no more chain breakages, but got round to using some Araldite, the steel version yesterday.

First impressions were that it seemed a much thicker and a much more sticky epoxy over having used JB weld previously. This version of Araldite only needed 5 mins to go off and set enough to hold the broken casting without the need of pinning it in place against a wall with a length of stick biggrin .

So higher hopes of this stuff doing the trick, but as always, watch this space and i'll let you all know how it bares up over time.

Peace and love to all WRRs,

Paul smile .

jono · Member

Hi all on the subject of JB weld have a look at the this www.youtube.com/watch the fun starts at 5 mins

Grassroots · Veteran Member

Ha ha haa. ...great video Jono. At least those guys efforts stayed stuck. I'm sad to say that after a great day out with the TRF last weekend, the damn casting has broken away again . It would appear that not JB weld or Araldite is good enough to hold this part down.....grrrr. The problem is that the bolt does need to be removed on occasion, and the pressure of this is just to much upon such a small surface area being bonded. It will always break when you have to touch the bolt.

The future choices seem to now be, run it with just the two bolts in place, or run it with the casting lined up in place bolted to the case saver tight, but only resting against the engine itself??? Bit concerned that the second idea might cause vibes from the engine to rattle the casting against it resulting in further damage....grrrr.

Any thoughts or bright ideas are always most welcome.

Cheers guys,

Paul.