It’s only 3 degrees out there but I’ve just finished a ride with a smile a mile wide. After 13 months of enforced layover, my Valkyrie had sounded out of sorts when I fired it up for the first time. Ran on three cylinders for a bit, then the other three joined in, but it was rough, especially below 2,000 rpm. Something was amiss – and the mile-wide smile is the result of some clever input from a guy called Andy: the Valk now runs like a dream.
My first reaction to the problem was to take the machine out on to a fast stretch of road for a 20-mile blast to blow the cobwebs away. It helped, but not much. My next recourse was to ask advice from the Valkyrie Riders Cruiser Club UK group on Facebook; as ever, members were quick to respond.
The most likely explanation was a build-up of ethanol at the bottom of the tank that had gummed-up some of the jets in the six carburettors. A couple of people recommended a product called Sea Foam, but it would take five days to arrive and I wanted the bike sorted faster and more cheaply than that. Another recommended using 98 octane fuel, which I tried (hard to find, even if you settle for 97); the engine seemed to run better on that, but it wasn’t perfect, didn’t provide a fix, and cost a fortune! A browse through Halford’s presented a few different products offering to clean your carbs, including good old STP; I had no idea it still existed, having proudly put an STP sticker on my helmet 50 years ago. The STP seemed to help, but the bike was still running a bit rough below 2,000 rpm.
The solution came by chance. Son-in-law Nikolas donated a folding bicycle to our son James. It needed both brake cables renewing, so I found a guy called Jason who sorted it all out at a reasonable price. He had a Suzuki 600 Bandit under a cover in his workshop, so we got talking bikes. He mentioned that a mate, Andy, who was an expert with carbs, had re-jetted the bike to suit the aftermarket pipes and it ran like a dream.
Andy turned out to be a qualified motorcycle mechanic who had never worked on a Valkyrie but was happy to strip, clean and rebuild the six carbs for me. You can see his neat, well-ordered approach in the lead photo. As soon as he had the tank off, he found an incredibly dirty air filter that could have been the main problem all on its own. That in itself was a surprise, because in the seven years I’ve owned the bike I’ve always had it serviced by Honda main dealers to maintain its unbroken full service history since it was new in 2002. I’d have expected the dealers concerned to have replaced the air filter whenever required; I’ll have to check through old paperwork to see whether they did.
The Valkyrie also has a pre-filter, a sponge-like thing that now lay in near-total disintegration over the air filter. Maybe that was causing the poor low-speed running? Or maybe it was the two split vacuum pipes, or the fact that some of the airbox rubbers connecting the carbs were coming away from the airbox? If this were a detective novel, there were already several credible suspects before he’d even got to the jets.
Andy fully stripped the carbs but found no unusual deposits – said he’d seen many worse examples. In any event, he soaked them in carb cleaner overnight and put them back together. He replaced the vacuum tubes and the pipe to the carb heaters, and re-sealed the airbox rubbers. He installed the new air filter (great service from Fowlers, by the way – ordered 18:35 Tuesday, delivered 08:55 Thursday) and made up a new pre-filter from Scotchbrite, which was another helpful tip from the VRCCUK folks on Facebook.
I knew the moment I fired it up that it was much better. Once warmed-up, it was a revelation: the original smooth, sweet-revving flat six was back. No roughness below 2,000 rpm, or anywhere else for that matter – just creamy power. Result! I have no idea which of the various maladies caused the problem, but there is no doubt some combination was responsible. It’s just great to have my old bike back. Now if only the weather would run so sweetly…
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