Hi Guys,

Lowsided my MC21 back in February and got a nice broken collarbone. Bent my Tyga tail, forks twisted, fairings, mirrors and blinkers munged.

After moving house and neglecting the bike in the garage for some time I actually pulled her out last weekend and replaced her bent tail, pulled all the dead fairings off and had a look at rebuilding a spare set of SP forks. Just before I put her away I couldn't help myself. I had to hear her run.

Started her up with a little trouble (battery rather dead) and god she sounded mean. Heaps of smoke which started to clear, but then, oh oh, she's spraying coolant out of one of her pipes. I guess the knock was a bit harder thank I thought - at least one blown head gasket.

So I move onto my spare engine under the house. I bought a parts bike specifically so I could have a spare engine ready to roll. Nice Dry clutch vs my old wet clutch. Although compression was good I figured I should leak test it. I finally managed to fashion a leak tester out of a piece of PVC pipe, and old fuel pressure tester and a tyre valve. For an exhaust plug I used a generic sink plug and a flat piece of metal. Seemed to be a good setup, what the air compressor on the valve and start pumping.

Nothing.....

Strange, when I held my hand over the end of the tube the pressure went straight up so can't be a problem with those seals. Checked the bath plug, seemed ok. Spark plug in tight. When I took the expansion bottle off the top of the carb boot and blew into it - a wierd whooshing sound. When I sucked it almost held a bit of pressure. That can't be good I thought.

Blocked up the other side with my rig. Needle on the gauge almost moved when I pumped. No whoosh sound when I blow into the bottle hole, slight resistance to blowing and sucking.

Hmmm. Does my rig just suck? (no pun intended)

I finally give up and grab the 2 stroke fuel tin. Rip off the carb boots and reed valve cages. Poor some fuel in the left crankcase......

A waterfall of fuel pours out from behind the flywheel! Now that was unexpected!

So I guess I'm pulling down this motor before it goes in the bike. At least I have a leak tester now.

So as the thread title suggests, how do I know if I need a new/remanufactured crank? It moves well and looks ok.

Can I just split the cases and replace all the dodgy seals?

Should I do the top end at the same time? What's the minimalist way to go?

Cheers

Clancy