Hi I live in the UK. I have a Sym Jet 50 scooter. I purchased it with just 3000 miles on the clock about 15 months ago. After about 500 miles it had quite a bad engine noise. Upon stripping the engine I found that the crankshaft had come apart at the bigend eye on one crank-web. I purchased a new crank (£203) :( and fitted it in the engine, only to have it come apart again after a further 5000 miles. Is this a common fault?...... because having worked on engines all my working life, (as a motorcycle mechanic) I find this quite alarming for any engine, but even more so after such a small amount of miles. Has anyone else in the world had this problem?

Regards..........Mr Alfred John Wolverson :( :( :(

Hi I live in the UK. I have a Sym Jet 50 scooter. I purchased it with just 3000 miles on the clock about 15 months ago. After about 500 miles it had quite a bad engine noise. Upon stripping the engine I found that the crankshaft had come apart at the bigend eye on one crank-web. I purchased a new crank (£203) :( and fitted it in the engine, only to have it come apart again after a further 5000 miles. Is this a common fault?...... because having worked on engines all my working life, (as a motorcycle mechanic) I find this quite alarming for any engine, but even more so after such a small amount of miles. Has anyone else in the world had this problem?

Regards..........Mr Alfred John Wolverson :( :( :(
try changing the the block 50 to 100.

i think you may have problems with the oil you're using, what brand of oil you currently use when it happened? did you buy the OEM crank or aftermarket? bearings & conrods on OEM cranks are crap you have to use high quality oil just to keep them from breaking too soon.

SYM Jet 100's never had a problem such as yours they've been known to go thousands of kilometers with cheap oil & they still chug along, maybe you got yourself a lemon?

Hi,
Firstly I should like to thank you Modular Overrider, and all the other people that have tried to help me through Motorcycle Philippines with this crankshaft problem. When I purchased the new crankshaft from my local scooter dealer, I presumed that it was a genuine Sym item, how can I tell if it is a pattern OEM type? How much would a "genuine Sym" crankshaft cost in the Philippines, including post and packing to the UK.

Again many thanks for all your help..... your friend for ever......John Wolverson from the UK.