Cannondaleriders

so i bought a spare engine and took it apart to make sure everything was ok, take a look, ready to run






ok yea i bought this from ABM-cannibal, with a bunch of other parts, dont know why it died, the cams and all look fine as did the rest of the engine until i pulled the head, now you could see the missing valves thru the intake and exhaust ports but i dont know why it came apart. this is a high comp 468 as i recall, timbo crank and 97mm piston kit. tyhe sleeve looks reusable, and crank looked fine too, but the case was cracked between the trans and crankshaftarea, ill get a pic if it too. but in the end alot of good spare parts and i might try welding the case to see if it works.

any ideas on why it failed?

I'll take a stab at it....
I'd say it dropped a valve or 2

i know that LOL but wondering why it did. the decomp was fine and under the valve cover looked totally normal, no damage you always have to wonder. its a shame the head is junk, nicely ported.

I would also make sure you send the crank to tim for inspection. It is possible the rod was bent when it smashed the valves/head. Worth a check before you slap it back into something and have the same thing happen again.

Just measure deck height from left ot right side. If it's under .010" difference from the top of the piston to the top of the sleeve then the rod is good. If it's bent bad you can eyeball it pretty easy. The one thing you really need to look at is a cracked case between the main bearing and countershaft bearing bores. Pull the stator to check the case under it. A crack will be very difficult to see.
So he said the engine was still running and ready to go?

no i knew the engine was bad, got it complete for 200 bucks, i looked hard at the rod and took some measurements and it appeared straight. the engine is about a year old. i havent checked the bearing bores but the engine is apart other than the trans now, i will look tonight and take a few more pics of the big crack thats already in the case

heres a couple pics of the case and the crack





didnt see and crack between the bearing areas though

Wow. I am pretty sure I built this motor. I built his previous one and after 2 years he sent it back because his engine case cracked along the same spot as this one. I wonder if there is some abot his mounts/frame that would have caused both of these.

When you tore apart the motor did you find anything that might have pointed to the cause of the dropped valves?

Oh yeah, take a pic of the port. I think it was a timbo port.

i have been looking for a junk head, do you want to sell it ?