What was your worst/ best BLOW UP!!

[Mick22]

Another thread reminded me of the worst or best blow up i had many years back, I've always kept a shelf of "reminders" (long before the worlds fastest Indian movie)



Here's my shelf



The dreaded 86 Model KX500 Barrell, this happened when I was earning about $100 bucks a week...it nearly broke me :'(
I was JRA and heard a noise like the chain had come off....got of to inspect and chain was fine...started looking around....doh!!
This is also the reason you won't find many 86 KX500's around, it was a major design flaw, look how little material holds the rear of the cylinder together

[BAHNZY]

Not mine, but I was there when it happened.
Best mate was building a 00 KX500 for Mark Sladek to run at Finke. The bike was on the dyno and was approaching 70HP after a bunch of runs and adjustments etc when the rod broke at the small end. The rod turned into a fly cutter and took out everything in its wake.

When all was pulled down, the list extended to;
A complete motor. The crank was rooted, both cases were destroyed, the main shaft in the gearbox was bent (where the rod belted it) and just about every gear was chipped or broken. Barrel and head were also destroyed. And the one that we didn’t get was the frame.
When the new engine was built and it was to go back into the chassis. the frame at the area of the lower mount was a good 5+mm smaller than the width of the engine. We worked out that when the rod belted the bolt it bent it and pulled the frame together. What a job it was to stretch the frame back out to get the engine in.

[David Lahey]

Mine wasn't the bike motor, but I managed to lock up the rear wheel of my RM250 SP370 hybrid in 1980 using my Minolta 110 underwater camera.
One of the bungees that was holding the camera to a small carrier behind the seat came undone and the other bungee flipped it down and around in underneath the rear guard. It wedged between the tyre and the RH shock. When it happened I was crusing a firebreak on my parents tree farm at about 70 km/h and it was so sudden I initially thought the motor had locked up.

[crossedup2]

Not mine either but was there when it happened and for the autopsy. In 98 Yamaha gave Tony Kirby and his mate two WR400 to cross Australia. Shortly after that run TK was riding it to Victoria with a group of us to the 6 Day. The shift fork had broken locking it in 4th and 5th (at about 100km/h) spliting 4th gog in half. One half ended up under the piston f#@king the top end and the other half stuffed the cases with 3 or 4 holes. Saved the clutch and flywheel. Every thing else ended up in a box and sent back to Yamaha Japan.

Odo was 10001km!

It was certaily a loud bang........

Peter B

[Lozza]

[holeshot buddy]

mine was my modern kx500af
had standard cast piston which disintergrated
bent rod smashed sleeve etc etc
it was in the second turn of a race i was in 5th
with 43 riders behind
luckily only 3 ran over me when it locked up at speed :'(
fixed it and fitted forged piston

[DR]

If the engine is still running but it has a conrod poking out the sump is that classed as a blow up? if not then I have been blessed in 40 years to never have blown up anything that engine with the leg out of bed was a good old sideplate grey..drove it 50k's home like that on about 1/2 cup of oil so being a car it doesn't matter and my record remains intact do seizures count??