new 1980 bike; bought with noisy engine.
I stripped it to replace the front cam chain guide, after finding the top strainer full of bits. The sump filter was breached.
On getting down to the crank, I found the right hand (as in clutch side) big end bearing shot. I mean really shot; like 3/4mm up and down play.The left hand side is smooth and well within spec. The little end isn't worn either.
Funny thing is that the engine has original std yam pistons, with rings that seem unworn along with an unmarked bore. All the other bits seem in really good condition.
Where I have had old brit bikes with knackered roller big end bearings, then the main bearings are rusty from lack of use and moisture. None of that here either
Obv, I have no idea on the history of the bike but the last few MOT's show no little to no mileage and it's likely spent it's life on the sidestand being run up.
Question is .. what else should I look at .. the oilways seem clear and everything .. I am just surprised it's knocked out a roller on one side.
Is there an oil supply issue I should be aware of ..
I think I will replace the one knackered side, but take a look at the good side at the same time.
I stripped it to replace the front cam chain guide, after finding the top strainer full of bits. The sump filter was breached.
On getting down to the crank, I found the right hand (as in clutch side) big end bearing shot. I mean really shot; like 3/4mm up and down play.The left hand side is smooth and well within spec. The little end isn't worn either.
Funny thing is that the engine has original std yam pistons, with rings that seem unworn along with an unmarked bore. All the other bits seem in really good condition.
Where I have had old brit bikes with knackered roller big end bearings, then the main bearings are rusty from lack of use and moisture. None of that here either
Obv, I have no idea on the history of the bike but the last few MOT's show no little to no mileage and it's likely spent it's life on the sidestand being run up.
Question is .. what else should I look at .. the oilways seem clear and everything .. I am just surprised it's knocked out a roller on one side.
Is there an oil supply issue I should be aware of ..
I think I will replace the one knackered side, but take a look at the good side at the same time.