Tuesday, 6 September 2011

NX650 restored

After a month and 500 miles of debugging the bike is pretty sorted. The rear master cylinder turned out to have a blocked return port. It was the one thing on the entire bike I didn't dismantle and clean, and the heat from the dragging pads cost me a new rear disc.

I replaced the cracked Bridgestones with new Dunlop Trailmax. Like other Dunlops they feel very stable, and glutinous as you lean over. They're good in the wet, and grippy enough in the dry for this kind of bike. If the Dommie is allowed onto Classic Bike's end of season Burn-Up at Rockingham circuit I reckon they'll be up to it.

I'd originally put Putoline 10W oil in the forks, which was too harsh. Honda recommend ATF which turns out to be quite light – equivalent to something like 2.5W Putoline. Since changing to that oil the front end is comfortable, though I've forgotten how crude these old damper rod forks were.

There are two problems left: first, the rear caliper bolts and bushes are worn, giving lots of lost motion at the pedal and a vague rear brake. I might need a new caliper, though it easily passes an MOT.

Second, the engine stalls round town and doesn't respond to Honda's recommended pilot screw adjustments. It could be that some fresh dirt got in there after the clean-up, so I'll check the pilot galleries. Otherwise the motor feels like new. Valve clearances are stable and I've revved it to 6000rpm without trouble now.

It's great to have breathed new life into a bike that belonged in a skip, and Fiona loves buzzing around the local lanes on it too.