TEETHING TROUBLES TR

Teething problems are to be expected with a ‘new’ bike that’s nearly fifty years old, but I’d been lulled into a false sense of security by the sheer exuberance of this diminutive middleweight in a lightweight’s clothing.

Then it happened. As I accelerated away and changed up, the bike stopped doing what it does best; ripping up the rev range like a tomcat with a ten foot head start on the vet’s snippers. It was as if the brakes were suddenly on. The airbox was still howling like a banshee, but the increase in speed was pedestrian compared to normal. I checked the plug caps in case one had popped off, but all was OK. So firing it up again (easily), I turned back for home thinking it felt like it was only running on one pot.

Checking the downpipes, one was much hotter than the other, which seemed to confirm my suspicions. Out with the plug from the cool side, and it looked wet… well, wettish, really, but not excessively so. Turning the engine over showed a fat spark, so I abandoned ideas of a wire adrift from one of the coils. The wet plug implied that fuel was getting through. ‘Expletive!’ I muttered, wondering if I’d holed a piston. It is a late 1960s Japanese two-stroke, after all.

Comparing kickstart resistance with each plug out in turn showed no difference. I hooked everything back up and tried again, just in case it had been nothing more than a plug tracking, and fiddling had maybe sorted it (I’m an incurable optimist). It sounded OK when fired up, but as soon as I rode away it was plain that all was not well.

Back home, I got the first clue. The cooler exhaust was hot, which it shouldn’t be if it wasn’t getting any fire through it. Was the carb only operating at tickover? I suspected a broken cable and pulled off the seat and tank (with its octopus-like bunch of hoses. There are only three really, but they get in each other’s way as if there are more) but where would the break be? And where would I get a multiple throttle cable set for a 1969 bike by the weekend? It looked like the soldering gear would be coming out, and some fiddling about making the right-size nipples ’cos the originals are cast onto the cables.

However, all was not lost. The visible parts of the cables looked OK, so I unscrewed the carb top and pulled out the slide – and there it was. The cable had unhooked itself from the slide. It was nothing more than that.

Reassembling it, I noticed that one of the hoses (running to the other carb) was only just long enough. You could twang it like Duane Eddy’s guitar string and it was in danger of popping off. So a trip to the local bike shop is in order, but test riding the bike showed all was back to normal in the performance stakes… until it went onto reserve.

Good grief! Have I used a whole tankful already? I only filled the bike up on Monday… but it’s been a lot of fun. Chris Parrott, member