gsxr renegade Posted July 3, 2021 Report Share Posted July 3, 2021 Sup chaps. I'm currently rebuilding a 2015 r1 engine after a top end failure, I'm pulling it apart at the mo and I've just got the crankcase apart and inspected the big end bearings. I'm not really sure what to make of the wear on them, does it look normal? The crank spins nice and freely, no free play and all of the conrods are nice and free on the crank. The crank journals are nice and smooth, no obvious damage. And the bearing surfaces are nice and smooth as well. Engine had covered around 7000 miles. Quote Link to comment Share on other sites More sharing options...
fastfreddybikes Posted July 3, 2021 Report Share Posted July 3, 2021 45 minutes ago, gsxr renegade said: Sup chaps. I'm currently rebuilding a 2015 r1 engine after a top end failure, I'm pulling it apart at the mo and I've just got the crankcase apart and inspected the big end bearings. I'm not really sure what to make of the wear on them, does it look normal? The crank spins nice and freely, no free play and all of the conrods are nice and free on the crank. The crank journals are nice and smooth, no obvious damage. And the bearing surfaces are nice and smooth as well. Engine had covered around 7000 miles. How much are a new set of bearings? Quote Link to comment Share on other sites More sharing options...
gsxr renegade Posted July 3, 2021 Author Report Share Posted July 3, 2021 31 minutes ago, fastfreddybikes said: How much are a new set of bearings? £22 per bearing. Quote Link to comment Share on other sites More sharing options...
CMSMJ1 Posted July 3, 2021 Report Share Posted July 3, 2021 I have no experienced view but were I looking at a motor in that state of undress then I'd want to fit new anyways. The cost of gaskets etc might allow man maths to be used as you'll not have to buy more of those if you replace shells now. 1 Quote Link to comment Share on other sites More sharing options...
Thunderbolt Posted July 4, 2021 Report Share Posted July 4, 2021 What went wrong with the motor? I am only looking at these photos on a phone, but I can see too much wear for the miles (7000) and this one doesn’t look healthy at all with bearing material contamination. Quote Link to comment Share on other sites More sharing options...
Damnthistinleg Posted July 4, 2021 Report Share Posted July 4, 2021 I'd be sticking new shells in and giving everything a very thorough flush and clean. I'd also be giving all surfaces a serious measuring to make sure it's all well in specification and properly round where it needs to be. Crank, cams, pistons, rods, etc. - the whole shebang. Is there any blueing on the cam/crank journals or marks on the piston skirts? It's daft not to be thorough when it's already in bits. It doesn't take long and I absolutely hate the thought of pulling a motor apart again because of cutting corners. Quote Link to comment Share on other sites More sharing options...
gsxr renegade Posted July 4, 2021 Author Report Share Posted July 4, 2021 Im going to replace them, just wondering if the wear looks normal more than anything. Cause of failure was a broken valve spring so valve/piston had a little meeting inside the head. The blockage on one of them is probably debris from that. The pistons that didn't explode look very good, hardly any carbon deposits and nice smooth movement in the bores. I've got new GYTR ones to go back in anyway. Quote Link to comment Share on other sites More sharing options...
Superdunc Posted July 4, 2021 Report Share Posted July 4, 2021 The bearings have been hammered from the piston valve interface. That's what the markings on the bearings in the lower crankcase are, the big ends will be fucked on the rod the failure occured on. Replace them all. Quote Link to comment Share on other sites More sharing options...
theo Posted July 4, 2021 Report Share Posted July 4, 2021 What @Superdunc said, and then throw the GYTR catalogue at it. Quote Link to comment Share on other sites More sharing options...
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