2007 CRF450 HOLE in the case. Help

I own a 2007 CRF450 that I bought used in February. I took it out for its maiden voyage yesterday and durin about the first 20-30 minutes, I noticed the smell of burning oil. Initionally, I thought maybe it was blow-by past the rings. I kept plugging away at laps and also noted a ringing sound when I pulled in the clutch lever. When I got the bike on the stand, I discovered a silver dollar sized hole just in from the water pump housing between the transmission cover and the right side case. It definately looks like something "left" the transmission. I rode it for awhile before the discovery. I soon will post pictures and will also drain the remainder, if any, amount of oil.

I don't know where to start. What did I trash as I continued to ride it unaware of the blow out? What might have failed? I know this will not be cheap to replace. The previous owner stated it had low miles on the motor and everything looks to have little wear. The transmission operated smoothly and I didn't notice anything rough during the ride. Even after the case was trashed. HELP!:thumbsup:

Here it is!


damn! that sucks. take it apart and see what broke.

That sucks I hope there is not a lot of damage to your clutch.

.. gonna take a stab and say the balancer shaft nut came loose, and your balancer gear came off the end of the balancer shaft knocking a hole out of the case. The water pump impeller shaft goes in the end of the balancer shaft, so it is POSSIBLE the water pump and/or balancer shaft bearing just were so toasted there was enough play to allow the balancer gear to hit the case. The weight on the balancer is heavy enough that with decent rpm, it would do that.

You may get reasonably lucky on this one and someone may be able to weld the part of the actual case half that is broke out, too bad it wasn't just the case cover. Take the entire cluch case cover off (motor does not need to come out).

It looks like the righthand crankcase cover bolt broke off from the main right crankcase. Hard to tell in the picture. But if this has happened, you will need to replace both of the mentioned cases. Pretty major job. In the picture it appears that the gasket is broken and some of both of the crankcases are missing. Possible to find parts on ebay if you cannot afford new. PM for who I use for great used parts or check with the thumpertalk store?

That is a by-product of trying to install a case by using the bolts to put it on and over tightened (prob cracked when you bought It, fell off on first ride)....... install clutch case by hand, then insert your bolts after you have the guides lined up and cases flush. (whoever did it!!!) You can find the clutch side pretty easily on eBAY, it's the sprocket side thats like Gold........

Thanks for the insights! Does anyone know what year right side case covers etc... will fit on the 2007? I will be tearing it down today or tomorrow.

So I have to start making some decisions. Replace piece-by-piece, or get a used trans/bottom end. Any thoughts?

I would start looking for a used bottom end on ebay.

i higly doubt overtigtening the 8mm head bolts would pull a chunk off of the case. A) the cover has no thread :thumbsup: the fine threads in the case half simply strip when overtighted.

OP.. I would get the clutch side cover off at least to see what happened in there..

i just totally rebuilt my engine after a similar thing. my counter balance drive gear broke in half. the hole in my case was much larger than yours. it looks like your gear is still in there though. pull the case cover off and see whats broken or missing. your up for a full rebuild anyway.

Got a new question. Do I need to buy both sides of the case or can I get away with buying just the right side case? I couldn't find anything missing upon disassembly. Either the previous owner dropped something in the tranny or my adorable 3 year old son dropped a bolt or something when I was doing the oil change.

i would try to jb weld the inside case and buy a new cover and call it a day. i didnt look close at the pic ,might be to big of a hole?

but you need to find out what happend though maybe a rock bounced over the guard there and broke it?

i replaced only the right side case and right case cover. plus a full rebuild of coarse. someone told me honda's are the only brand that you can replace 1 side only.

Thanks gotwings! The riding season isn't totally over for me!

I have a right side case cover and factory gasket I'll sell you if you haven't found one yet....:ride::thumbsup:

Thanks for the offer Jason, but I did find one on eBay last month and already bought it. I appreciate it!

Thanks gotwings! The riding season isn't totally over for me!

Glad I could help ya!!!

Thanks for the offer Jason, but I did find one on eBay last month and already bought it. I appreciate it!

No problem man... Wish I woulda read this thread a little earlier, coulda helped you out then... :ride::thumbsup:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now