How would you fix this? - Motorcycle Drain Bolt

SammyChevelleTypeS3

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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.

View attachment 114801
If its thin aluminum? ugh....
 
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The actual hole has cracked out into the case, you would have to squeeze it back into shape to make the hole proper again before welding if you want to use that actual drain hole. If you can do that without creating more cracks, you then need to rethread the hole. If that all works out, I would go with a drain valve in there so you never touch it again.
 

AlpacaBowl

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Ive got to try and salvage it. Im taking it over to a machine shop tomorrow. I'll update the thread once they give me an opinion.

Again, thanks for all the comments and suggestion's.
 

AlpacaBowl

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Weld the plug right into the hole. Use an oil extractor to change. Cheap and done.
Trust me, I'd be ok with this if I knew for a fact that I was keeping this bike forever. The reality however is that this bike may change owners one day and buying an extraction pump may just be another extra step which would dissuade some buyers.

It is an entry level bike.

Thanks for the input, I kinda think this is a last resort.
 
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It might be an entry level bike but it has a big heart. :)

CBR.jpg
 

ZeeOSix

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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.
If you attempt a repair, I'd drill the drain plug for some safety wire so you can torque it just enough to seal without re-cracking the repair, and then safety wire it so it won't move.

Then while running it that way, I'd put an order in for the back-ordered new case and swap it out when you can get one.
 

ZeeOSix

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Does this engine really need to be removed from the bike and the cases split to install the new case? Lots of newer bikes have a separate drain pan case that can be removed with the engine in the bike.
 
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Does this engine really need to be removed from the bike and the cases split to install the new case? Lots of newer bikes have a separate drain pan case that can be removed with the engine in the bike.
It does. And to split the cases you have to remove the cylinder so it's going to be a complete disassembly. Fortunately the engine can be laid on the right hand side and the cases can be separated without disturbing any of the transmission components. The timing components are on the right hand side but again, the cylinder must be removed to get the cases apart. Even if the cylinder studs could be removed separately there is still the issue of resealing the base of the cylinder.

I would disassemble this engine even if I were going to do a weld repair. The weld repair needs to have a full penetration buildup of aluminum along with hand machining to assume some semblance of original contour and you just don't get a quality job if it's assembled.

I'd hope the OP publishes his finished results once it's all back together and running.
 
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I see no way to not remove the case even to weld it. For a weld to work you have to get the oil contamination off the metal. If you have to split the case, i see no reason to weld vs replace the cover, unless you just can't get the cover. I think any weld attemped with the cover on, will have oil contamination and probably won't work.
 
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+1 For under $150 for a new part the last thing I am doing is welding it. Being a small single cylinder this is a very simple engine to remove and split.
 
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My guess is that a good TIG welder will want the case disassembled and clean. The welding work may cost $145 so you are better off just buying a new case half. You can probably do an effective epoxy repair but “probably” is the key word. If it should fail or leak you might have hot oil spraying all over your rear tire. Not worth the risk.
 

AlpacaBowl

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OK So Update time...

I tried to install a rubber grommet designed to replace a metal drain plug for a car oil plan that is stripped out with no luck. For some reason it wouldn't seat in the case. While I thought I had it installed completely, I removed the old oil filter which was still in the bike and inspected it. Despite being dirty, there doesn't appear to be any metal in the filter. Also, releasing the oil filter housing, released some oil back into the crankcase internally and there I was able to see the plug was not doing a good job sealing. Having not wanted to waste 2 quarts of oil, I moved on.

I also tried to tap some threads with an oversized bolt I had sitting around which is specially designed to help repair threads but it doesn't have enough material to thread correctly.

Finally this morning, I went out to a machine shop this afternoon and showed them the bike. They agreed that they could likely fix it but would be worried about future cracking and were hesitant to take on the work. I have to say it was a real stand up shop and I ended up taking the bike back home.

I've got one more trick up my sleeve for which the parts come in tomorrow afternoon so I hope to have an update then.

If this doesn't work, I'll be pulling the engine and attempting to swap out the case. Again, its more of a learning experience and its been quite fun to wrench on so far.

Wish me luck!
 
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if its a rubber expansion plug it needs a round hole (it 'grows in size' in a 'round way'). That hole is no longer round. Used one ona korean awd rear drive shaft hole so owner could keep using car, parts (junk yrd/dealer/aftr mrkt) - unobtainable, owner -0- $. Blocked up tranny so as to not loose lube, she's still drivin it. Signed a doc here to take full responsibility B4 leavin da shop.

Enjoy the nxt phase: #2. Let's hope 'that is it'/goes well~
 

AlpacaBowl

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if its a rubber expansion plug it needs a round hole (it 'grows in size' in a 'round way'). That hole is no longer round. Used one ona korean awd rear drive shaft hole so owner could keep using car, parts (junk yrd/dealer/aftr mrkt) - unobtainable, owner -0- $. Blocked up tranny so as to not loose lube, she's still drivin it. Signed a doc here to take full responsibility B4 leavin da shop.

Enjoy the nxt phase: #2. Let's hope 'that is it'/goes well~
Thats exactly it. The plug did sit well but I didnt want to risk dumping a ton of oil.

Regardless, it was $8 and I'll throw the plug in the toolbox for later.
 
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