I have a 638 jawa, i love it and after some simple adjustments it is quite reliable, and i want to use it for holiday travel again, only 1 thing worries me; the middle crankshaft bearings broke down at 23.000km (is very soon i think) i got them replaced and re-installed the crankshaft.
Also i made the 2 holes in the block, which give way for the mixture to lubricate these 2 bearings, a lot bigger, i hope they get better lube and cooling now.. last year i travelled 6000km through Europe with it and used it for everyday transport..
So, whats the problem>?
i want to go on holiday to Romania next week, but the bike has run now for 46.000km, so statistically the middle bearings are prone to break.. unless the quality of the original bearings were bad and the enlargement of the 2 lubricating holes have effect.
So what if i am in the middle of nowhere and the crankshaft breaks down- like last time- without warning?
Transport back home is expensive and maybe unnessecary if there is an adress in your country, or Slovakia Or Romanai(cannot find a jawa club in Romania)_ where i can buy and install a new crankshaft.
Can you help me, or say i am stupid and have to get an new crankshaft to be sure first?