Thank you to everyone who takes the time to answer questions here.

I've gone this long (9 months) without posting a single question because of how much support and information there is on this forum!

The search function and me have become very well acquainted over the corresponding months.

My issue though is one that I could not locate anywhere. So the time has come....

Bike in question is an MC 21. It has a dry clutch which I'm currently in the process replacing.

While cleaning the case I noticed this crack where the coolant distribution fitting goes.

Anyone else ever encountered this?


Any help is greatly appreciated and thank you!

does the crack go all the way through? If not im sure its nothing a TIG weld cant fix

There's only 1 good type of crack, but this isn't the site to discuss it... 🤣🤣

While it's not certain to say 100%, just from looking at a couple of photos, that doesn't look to me to be terminal in any way. However, while the motor is apart, it wouldn't hurt to pop the casing to a local engineering firm and have them inspect it and give a professional opinion. They may well say that running a bead over it is a bit overkill.

To me it looks like maybe a bit of contamination in the casting, that's just "flaked" a little near the surface. It's a non-structural part of the casing, and the torque values for screws in that area are very low. I'd be extremely surprised if it failed catastrophically or too quickly to not notice and kill the motor before any damage was done through loss of coolant. That crack would need to run very deep for it to be a serious concern really, IMHO.

Again, very hard to be entirely sure just from photos, but it's probably fine.

I'd say it's similar to the other side, just a bit more pronounced!


_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

prelude2.2 wrote:does the crack go all the way through? If not im sure its nothing a TIG weld cant fix

Thank you for the reply prelude2.2 !! Crack does not appear to me to go all the way through. Seems to be on the surface only.

Not too fussed about it if it's strictly a cosmetic flaw.

Andy wrote:There's only 1 good type of crack, but this isn't the site to discuss it... 🤣🤣

While it's not certain to say 100%, just from looking at a couple of photos, that doesn't look to me to be terminal in any way. However, while the motor is apart, it wouldn't hurt to pop the casing to a local engineering firm and have them inspect it and give a professional opinion. They may well say that running a bead over it is a bit overkill.

To me it looks like maybe a bit of contamination in the casting, that's just "flaked" a little near the surface. It's a non-structural part of the casing, and the torque values for screws in that area are very low. I'd be extremely surprised if it failed catastrophically or too quickly to not notice and kill the motor before any damage was done through loss of coolant. That crack would need to run very deep for it to be a serious concern really, IMHO.

Again, very hard to be entirely sure just from photos, but it's probably fine.

I'd say it's similar to the other side, just a bit more pronounced!

Thanks for the reply Andy.

That is very reassuring. It really does appear to be cosmetic.

Does not show anywhere near the mating surface or in the threaded hole.

I will follow your suggestion and take it to a shop to get checked out though. Would rather avoid welding on it but I'll see what they say.

Thank you again.

thedevsla wrote:
Thanks for the reply Andy.

That is very reassuring. It really does appear to be cosmetic.

Does not show anywhere near the mating surface or in the threaded hole.

I will follow your suggestion and take it to a shop to get checked out though. Would rather avoid welding on it but I'll see what they say.

Thank you again.

Yeah, as I say, there's very little torque on those two screws (water pump cover & distribution piece), so in my personal opinion, you're not going to fracture the cases any more when you reassemble them. If I had to put 50p on it, I'd say they'll be fine.
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

I was wondering if an epoxy might work https://uk.gorillaglue.com/gorilla-epoxy/
_________________
Why do things simply when you can complicate them

I’ve seen marks like these a lot on Japanese casings and castings over the years. They are casting faults (almost like creases that form when the molten metal is laid down) and as they get muck and dirt in them over time they start looking like cracks.
Imo they are nothing to worry about.

RobH wrote:I was wondering if an epoxy might work https://uk.gorillaglue.com/gorilla-epoxy/

Thanks for the suggestion. I will look into the epoxy route if it's deemed to be strictly cosmetic. May just leave it though.....adds a bit of character.

Zeus wrote:I’ve seen marks like these a lot on Japanese casings and castings over the years. They are casting faults (almost like creases that form when the molten metal is laid down) and as they get muck and dirt in them over time they start looking like cracks.
Imo they are nothing to worry about.

Thank you Zeus! Thats a load off indeed.