Hi All,
I wonder if the more experienced eyes on NSR World would mind taking a look at an MC18 cylinder that we’ve just purchased for our MC21/MC18 hybrid race bike:-
https://www.flickr.com/photos/124222392@N04/
It’s hard to see from the pictures but there’s a hair line crack in the exhaust port bridge as highlighted in red. Having taken some time to gather our thoughts and consider whether it’s worth the risk to use it as a short term fix while my other cylinder is off to the platers, we’ve decided against it as broken collarbones, numerous dents in the bank balance and years of repairing fibreglass bodywork have taught us that it’s not worth taking risks when putting together a 2 stroke motor especially for race purposes.
We’re thinking that eventually the nickasil plating will flake off the bridge at the position of the crack resulting in a seizure. It could be first time out, or in 2 years time but we’re sure that it’s certain to happen particularly when on the exhaust port side of the cylinder which runs hotter than the intake side and it being the biggest port so there’s less route for heat transfer between the piston/cylinder hence this is where most seizures happen.
We would be keen to hear your thoughts and if you concur with our line of thinking? Would you be prepared to take a risk on it? Your honest opinion on this matter is welcome and if you think we’re being over cautious then please let us know!
Many thanks for your time!