06' 450 thrown chain broken case pics

After 4 weeks of anticipation, 3 hours of preperation, and 2 hours of driving, we go riding for 5 minutes and the chain gets thrown and hits the case right at the top of the front sprocket. Oil was squirting out the hole for a couple of seconds until I shut it off. After looking at the chain it looks like it seperated at the master link.

Does the case have to be replaced or is there an easier fix?




Looks like a job for some JB weld!!!!

I don't know what JB Weld is but I put a hole in my Landcruiser sump acouple of years back and had the hole welded by someone who does aluminium welding here in Dubai. (LC sump is Aluminium cast just like the bike). Weld worked perfectly and it cost be 300 dollars complete. Since it was an engine out job I guess the welding wasn't too much. I would think this would be repairable.

doesn't your bike have that chain gurad to prevent the chain from doing that

Like said, have it welded and never worry about it or JB weld it (you mix 2 substances together and apply it like epoxy or glue) and it will probably work.

was this a stock chain/sprockets combo? You must keep an eye on the wear on the clip for the master link....plan on swapping them out before the chain.

If it was my bike I would get a new case since it is so new I wouldn't gangster rig it.

JB weld will work great for that :excuseme:

have it welded

Damn. Only thing I would do is get a new case, because I want it done correctly. Didn't you have the case saver on?

P.S. Where in Michigan do you live, also, what skid plate is that?

Looks to be a GYTR skidplate.

Looks to be a GYTR skidplate.

After 4 weeks of anticipation, 3 hours of preperation, and 2 hours of driving, we go riding for 5 minutes and the chain gets thrown and hits the case right at the top of the front sprocket. Oil was squirting out the hole for a couple of seconds until I shut it off. After looking at the chain it looks like it seperated at the master link.

Does the case have to be replaced or is there an easier fix?


Sorry to see your misfortune! Was this a used bike? Reason I ask is maybe your dealer will help with a good will warranty through Yamaha. If not just replace the case, use a good chain, and be done with it.

I went through the same thing on my '03. The chain just jumped off and the stock case saver doesn't do squat. The chain just broke the bolts and pushed the case saver into the clutch actuator. I fixed it with JB Weld about 4 times but it kept drooling so I bought new cases. It was my first time taking apart a 4-stroke but it has given me no problems for two and a half years.

The cases come in matched pairs and can't be changed on just one side. It was a big pain to get all the bearing out of the old cases. Other than that it wasn't too bad.


I just replaced my center cases on my 06. I was running Excell wheel sets(the kind that have the interchangeable rings)and the ring on the wheel broke and threw the chain. It trashed the stock case saver and broke the lower post off of the case. I tried to weld it but the heat slightly warped the case so that the shift fork would bind. You have to buy the cases as a matching set and they cost me about 650.00. I hate to think what the labor would be to pay someone. I did all of the labor myself. I would either JB weld it or spend the money and fix it right. Don`t take the chance of hurting your tranny.

Try a weld, all you have to lose is a few bucks, if that doesnt work you know what has to be done, try your cheapest option first, and keep the gaurd on there

Isn't that a oil passage? Pressurized I assume? Kinda a tricky fix, be careful not to impede oil flow to anything.

Didn't you have the case saver on?
That's what I was wondering? There's no way the chain would have torn the case saver off and left the screws in.

We took the sprocket cover off ours right away, too, but the case saver HAS to be there (requires shorter bolts.) Stop taking parts off of your bike that you don't understand the function of.

Stock chain, huh?

Well, the bad part is that it looks as if you broke into the oil feed passage between the transmission shafts. Either welding or epoxy repairs will likely block off the passage and starve your output shaft assembly. You COULD have that case repaired IF you take it to a competent welder who is also an accomplished machinist. He will need to weld the hole shut, open up the the oil passage where it was originally drilled, an re-drill it. The engine will have to be completely disassembled.

Crankcases are sold only in pairs.

Don't blame the bike; this one's on you.

Nice post count Greyracer513. :excuseme:


I was hoping you would chime in Grey. Although it's kind of harsh of you to assume that I would "take parts off of my bike that I don't understand the function of". I haven't taken anything off the bike. As a matter of fact I've added hand guards, radiator guards, skid plate and a rear brake master cylinder guard. I never heard of the case protector before today and I read through TT daily.

My brother-in-law, a mechanic, said almost the exact same thing Grey did about it being an oil passage and having to drill it if it is welded.

I was looking for a second opinion that hopefully didn't include motor removal and case replacement. But it looks like thats what its going to be.

How does $900 sound for the labor and the cases if I remove the engine myself?

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