XL600 Engine Rebuild

Got a 1984 XL600R to repair. Seller thought timing chain had snapped so bought to break for spares if the damage wasn’t worth repairing. Had a look inside cylinder with endoscope, no valve fragments or visible damage. Great thought I, probably jammed timing chain. Looked at dipstick, not great, no oil. Seized piston then. Oh well I thought I would have a look anyway and maybe look to see if I could source cheap replacement parts…this of course turned into a full restoration…well breaking for spares is so boring compared to getting something on the road again

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Struggled for 20 min trying to get the engine out. Thought about giving it a rest for a bit and the damn thing nearly dropped out on my foot.

Tried removing gudgeon pin with homemade tool but it’s completely seized onto the conrod and piston. I don’t really want to replace the conrod if not at all necessary so will have to cut the piston off…after wrapping the whole thing in clingfilm to stop everything falling inside the engine.

Finally managed to get the damn thing out but wasn’t exactly surprised to find the conrod knackered…oh well back to eBay. The conrod is pressed on to the crank and needs a big press to get it on and then should be balanced after so I was pleased to find a full assembly from a low mileage bike. Will continue strip down whilst waiting then.

Got further with stripping down today, a few siezed bolts but nothing too major. A whack with a rubber mallet and the think split apart like an Easter egg.

The cylinder arrived today so was able to pressure wash, prepare the mating surfaces and hone before starting cleaning and de-greasing the other parts to get ready for respraying.

The new crank and piston are in and more bits are sprayed so it feels like its coming together now…

I ended up fitting new bearings pretty much throughout and oil seals which disappointingly didn’t come with the gasket set. It also made sense to fit a new timing chain.

Everything is going to plan. One noteworthy thing is the camshaft must go on with the lobes down at TDC on flywheel and the two markers on the camshaft sprocket. However remember when checking afterward that the valve opening/closing cycles are correct (with a long screwdriver through the spark plug hole) the engine needs to be turned anticlockwise NOT clockwise. I thought I had done something seriously wrong as the valve cycles didn’t match the piston position until i realized I was turning the wrong way.

Well there it is. I just have to do the rest of the bike now…