How Fix Crack in the Engine block

pasoalf · **Posted:** Wed Jul 29, 2015 4:55 pm

Has anyone experience fixing something like this?

I did google a bit. jb weld seems to be a dreamstuff???

higgy · **Posted:** Wed Jul 29, 2015 8:15 pm

forget JB find a talented welder or get a new head

there are compounds to fix but JB is not one of them, Alumiweld in a pinch as long as it is not a stressed component

paso750 · **Posted:** Wed Jul 29, 2015 8:22 pm

pasoalf · **Posted:** Thu Jul 30, 2015 5:50 am

No idea how this happened... I guess there was an inpact from the chain....
Question is how to fix.... :,(

Mc tool · **Posted:** Thu Jul 30, 2015 5:55 am

What normally happens when the chain either derails or breaks is that it rolls up on the front sprocket until the diameter is such that it pushes the crankcase out of the way ...... and yours is mild compared to some of the damage I have seen

Duc906 · **Posted:** Thu Jul 30, 2015 12:20 pm

A good engineering/welding shop will be able to repair that crack unfortunately it means that the motor will need to come out and stripped down to do it properly. Been there done that. :-(

MarkST · **Posted:** Thu Jul 30, 2015 2:13 pm

paso750 · **Posted:** Thu Jul 30, 2015 3:51 pm

is it possible the caser saver (which does not fit on 750 engines btw) withstands the forces and stalls the engine instead (shredding the gearbox). Also it usually is quite close to the chain so maybe it prevents the chain to roll up between engine case and sprocket.

Mc tool · **Posted:** Fri Jul 31, 2015 1:30 am

I think the real truth is that if your diligent enough to fit a case saver your probly diligent enough not to let your chain/adjustment get so bad that it could fail

.Please don't refer me back to the sprocket bolt thread where I admitted to "chucking a chain thru the cases " ...........that must have been someone elses fault :roll:

. Its ( the case saver ) like carrying a puncture repair kit.........your guaranteed not to need it as long as its on board .... soon as you leave it at home you get a puncture :mad:

Derek · **Posted:** Fri Jul 31, 2015 8:32 am

riascns · **Posted:** Mon Aug 03, 2015 12:15 pm

Some alloys are porous and take up oil over time. These cant be welded successfully. Found this out when I went to have a crankcase on my motocrosser welded.

Metal stitching is the best type of repair for this situation as it is done cold and so there is no shrinkage or contamination issues, but it is a specialist job which probably means it is very expensive.

Probably better to get some crank cases. Will probably end up costing the same as having your cracked one welded but the integrity will no longer be suspect.

How Fix Crack in the Engine block

Who is online