OzVMX Forum

Marque Remarks => Yamaha => Topic started by: lms6201 on August 23, 2009, 08:29:33 am

Title: how lucky am i ??
Post by: lms6201 on August 23, 2009, 08:29:33 am

just yesterday i,m blasting ,round the forestry on the 490 L after fitting the new 42 mm mic. ( i have conditional rego on it )  after about 20km it fails about 3 k from the car ,  teardown reveals a bigend failure , rollers all around one side, rod elongated, crank pin moving in crank half ,  this is the lucky bit ,  it stayed intact , no rollers through the top end , or jammed under the crank halves , no rod through the case , just ground up big end cage through the mains , that,s it , and i scored a good crank a few months ago ! ,   makes up for going to lowmead reloaded , and a trailer spring goes sideways and through a tyre , and shortly after that getting rear ended by a tandem tipper and dog , knocking bikes over , bending trailer ect   

Title: Re: how lucky am i ??
Post by: YZ250H on August 23, 2009, 08:55:52 am

Sounds like you should have stayed in bed yesterday mate  ::)

Title: Re: how lucky am i ??
Post by: VMX247 on August 23, 2009, 09:18:18 am

 :o  glad that day is all over for you  :o 
have a good one today  8)
cheers

Title: Re: how lucky am i ??
Post by: Nathan S on August 23, 2009, 05:48:13 pm

You're lucky!

I had a YZ125E big end let go during a race - it sprayed half the rollers through the engine. It killed the piston and mildly damaged the head, but didn't even put a mark on anything else - I figured that it was the luckiest BE failure ever, but I was obviously wrong. :)

A work mate has a KTM300 piston on his toolbox - its a huge mess, with mangled BE rollers jammed into all sorts of weird and disturbing parts of the piston.

Title: Re: how lucky am i ??
Post by: oldyzman on August 23, 2009, 07:20:31 pm

Hey Nathan, your coment worries me as i have a 125E and a KTM300, and they arte the bikes i flog most of all. By the way i must get your address so i can send you the air jet that suits that VM carby, As i have finally worked out it does require a jet ie a 2.0mm
Cheers

Title: Re: how lucky am i ??
Post by: Nathan S on August 23, 2009, 09:11:04 pm

Don't let it worry you - I fitted the YZ with a particularly sus, used crank. It lasted a full day of practice, but let go on race day.

The KTM300 is a really early one (85 - I think that makes it the first year of them), with an appaulling reliability record - which I suspect relates to the owner's Mikuni conversion. He replaced it with an '01 380 and couldn't be happier - and despite his stubbon insistance that its not getting worn out (it clearly is), it keeps running.