How would you fix this? - Motorcycle Drain Bolt

Joined
Jul 27, 2022
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67
Location
Braidwood, IL
I recently bought a lightly used CB300R in great shape. Only 2,200 miles and I managed to pick it up for a pretty good price. There seems to be only one problem. The PO had the dealership perform the first oil change and they really torqued the drain bolt down to the point when the owner went to perform the second oil change the bolt broke and cracked the case. Again, I bought it this way and the seller simply wanted to offload it instead of dealing with the damage.

I understand replacing the side of the case is the right way to fix this but im open to some other ideas. Ive had experience with Helicoiling and retapping before but not on a bolt this big.

With the cracks, I was thinking that maybe steel stick a Fumoto valve would work as well.

IMG_6160.jpg
 
I could most likely weld repair this if the threads are still there. Try and find an experienced aluminum TIG welder in your area.
 
I could most likely weld repair this if the threads are still there. Try and find an experienced aluminum TIG welder in your area.
This is what I'm leaning towards as well.

How much is a new oil pan on these?
Not too much for that side of the case (remember its a motorcycle), about $150 but they're out of stock everywhere. I'd rather try and fix what I have then split the case.
 
I would think that the only way to repair this would be to weld the area and re-tap the drain hole. If not this option you'd have to replace the crankcases and that would be expensive.

Edit note: I was surprised that you can buy the crankcase halves separately. The left crankcase half can be purchased for $145. If you can't get it welded then you could have a fun little project.

Reference Part Number 11200-K33-D00 (left crankcase half)
 
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Replace the case, you will most likely have to split it to get it welded properly anyway. Do not use steel stick, JB weld or any sort of repair putty, you will loose the plug, valve and all the all the oil then you will need more than a case half. Sometimes it pays to do it right once and be done with it.
Plus maybe going down as well...
 
I have frequented motorcycle boneyards for parts on my older stuff. Maybe you have one around you or some on line and some list current inventory. Good luck.
 
If you don’t do the proper repair, you will have problems down the road. Get that part of the crankcase and be done with it.
 
I'm going to start making some calls to local places who may specialize in these kinds of repairs. I was recommended to start with Porsche repair since they are usually aluminum and high dollar engines.

I've busted enough cases on the trail to trust Steel Stik and JB weld to a certain point. But the rethreading and spreading of the crack is what concerns me.

Ive drilled and tapped JB weld before but it wasnt for a sump drain.

Thanks again for the helpful replies.
 
I would think that the only way to repair this would be to weld the area and re-tap the drain hole. If not this option you'd have to replace the crankcases and that would be expensive.

Edit note: I was surprised that you can buy the crankcase halves separately. The left crankcase half can be purchased for $145. If you can't get it welded then you could have a fun little project.

Reference Part Number 11200-K33-D00 (left crankcase half)
Thanks for providing this. Do you see it in stock?

Im not about to start disassembling the engine without at least trying to repair.
 
weld it and use one of those expanding rubber drain plugs? ugh hack job though.

I think if i was the Previous owner I'd have went back to dealer and had a conversation.. story sounds off.
I dont even see a thread in that hole.
 
I don't know if a good welder can do that job or not, that AL will be extremely dirty as it has been submerged in engine oil and there is no way to preheat the piece.
If it can be welded, then do that and install a time-sert.
 
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