Scooterotica

That looks a complete mess, any more info? Any warning signs? Was he wanging it at the time?

I have a Mec crank in my TS but I had the rod changed and bearing changed (110mm Yam rod) mainly to give the rod an easier life.

was he using piston shims?

just looked again he wasn't, I'd thought maybe the rod had been shimmed at both ends.

Didnt the same happen to Jordan (Serveta Kid) with a MEC Crank ?

this happened to me on a jet ski about 20yrs ago in my haste to get out on it I forgot to put 2stroke in but f%%k it flew for a few min's well impressed no inertia to cut all around but a beautiful hole in the crankcase about the size of a 50pence managed to get it repaired but i think that maybe to far gone . i feel his/her pain you know that's going to cost.
just thought i'd share.
Den

Toddy wrote:Didnt the same happen to Jordan (Serveta Kid) with a MEC Crank ?

Has the rod snapped? (cant see the pics) Mine did snap, but I had mistakenly shimmed it on both the big end and small end. Learn by your mistakes and all that... However, I wont run a MEC rod as I have heard of more than just mine snapping, and these had been shimmed correctly. So I run a jap rod now.

Hi guys,
I'm new to the forum, Lambro posted the pics for me last night. ( cheers bud )
not a good day yesterday, on my way back form Woolacombe.
There was a bit a bump and a clank and I lost power.
Difted over to the side of the motorway kicked it over and no compression.
I thought I holed a piston, when I looked holy f*******
I was flat out middle lane running fine when it happened, god knows what happened to the bits that flew out behind me.
The engine has been built for three years and never missed a beat.
I came up the same part of the motorway from Exmouth last month never stopped once and full throttle ran beautifully.
The crank snapped close to the small end, spun around cut the engine in half and then snapped at the base.
On the plus side Woolacombe was good and I now have something to do at the weekend. lol
If any one knows of a Jet 200 engine for sale give me a shout.
I suppose one question for you guys is am i expecting to much from my engine and I should have backed off.
Let me know your thoughts.

Servetta200 wrote:.....I suppose one question for you guys is am i expecting to much from my engine and I should have backed off.

A longer rod, 110 or 115 with a corresponding packer under the cylinder will reduce the side loading on the small end which also makes for less vibration and maybe longer life?

I had the big end eye break away on a MEC race crank too, which also did a similar job of smashing out of the casing. I was lucky that it happened on the stand whilst I played with my jetting! This was a week before a Euro jaunt!

Adam

Adam I think mine must have fractured just down from the small end bearing.
Is that the same as yours?
Im told Mec cranks are good and its unheard of for them to break!!
What did you fit as a replacement?