It's been a while and I've forgotten what I was told last time I asked, so:

How much do I take off the barrels, and from which end, I assume the block end is safer than the head end?

I partially seized it last week, but stopped and turned it off before it seized fully, there's no scoring or glazing on the barrels, they'll be fine if I just hone them won't they?

Is it safe and/or worthwhile taking any material off the pistons, even just to get them matched perfectly?

What size drillbit should I order to open out the jet in the carb?

Has anybody got a set of decent 9:1s they'd like to sell and post to me?

Should I bother balancing the flywheel after I've machined it down to a frisbee?

Why did the engine partially seize?

Good question. It was full of fresh oil, the timing might have been a smidge too advanced as it did pink if you were a twat with it, but it suddenly got really hot, seemed much hotter one side actually, and just came to a halt. I'll probably rectify a few things that might have caused it when I stick it back in.

Strange how one side got hotter than the other.Oil cooler O.K.?

Russell,
about 0.5mm/ 20 thou.
Take the material off the top spigot, otherwise the rings will be prone to fluttering and breakage as they cross any wear ridge at the top of the stroke.

Any sign of scuffing on the pistons? It's usually in line with the 3 studs.

Got one of these recently, to save trekking to the shop with pistons to be weighed.
All you need then is a file...
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWNX:IT

If you've got a pin vice, I can post you a 1.07 drill bit, or if you've got an M5 x 0.75 or 0.8 tap, I can post you a 107.5 Mikuni jet.
Are you using an original air box or an open filter? If so, make the above 1.1 and 110.0

'Pass' on the other questions...

ken

Thanks Ken.

Pistons didn't look too bad, I'll have a closer look tomorrow where you suggest.

Scales look a bargain, I'll have a set!

Can I post you a jet, an SAE and some ale?

Original airbox that's fallen to bits, the lid's been screwed down three times now and still comes off. Feckin' thing.

"For jewelery"...

Yeh, right. That's what most get sold for, I'm sure...

You're right, I bet most go to people like Ken for weighing pistons and engine parts.

Got this problem myself, early morning start...funny noise...(after getting out of bed)....lid on air box blown off again. Been screwed down and rips itself off the screws.....driving me nuts...whats it all about ?

Russell,
also worth checking that the top 2 rings haven't been nipped in their grooves.

Might be easier if I post you a tap and a couple of Mikuni jets to try.
No worries about ale, as it's just about off the menu for me...

Best way to repair one of the plastic air boxes with a lid which comes loose is with some 6mm threaded rod, plus a few nuts and washers.

Reading from the bottom upwards...
nyloc nut,
repair washer,
base of air box,
repair washer,
plain nut.

Lid,
repair washer,
nyloc or butterfly nut, but don't wind it down too hard. (think rocker cover)

ken.