Yamaha Virago 535 Trike
We had never had a trike on the rolling road before, so when we got a phone call asking if we could do a power run on this Yamaha Virago 535 we had to give it a go. Luckily we had no issue reversing the trike onto the rolling road and very soon we had it strapped down ready for a power run.
The owner had his suspicions that the trike wasn’t running to full power after recently buying it. As we ran it on the rolling road his suspicions where confirmed as the trike was only producing around 9bhp. These are supposed to produce between 38 and 44bhp. There was something wrong…
As we began to remove the baffles from silencers on the trike we found that only one side of the trike was fuelling. As you can see in the picture.
With only one side of the trike receiving fuel, we needed to further investigate the engine set up. As we began to strip the engine down it was apparent that the trike hadn’t been serviced for a while. Spark plugs where fouled and diaphragms weren’t sat correctly. Each time we found one small issue we would build the trike back up and run it on the rolling road. Making only a slight increase in power we continue to take the engine apart checking more components.
We even put a camera down into the air box so we could see what was happening when the carburettor engine was running and this is where we struck gold 🙂 One of the slider valves wasn’t opening when the throttle was opened up. Now we knew what was stopping the fuelling we had to investigate why this was happening. Again the engine was stripped down and we began to check every single component. This is where we discovered the needle in the slider valve had become lose and wasn’t moving when the throttle was opened.
A pretty simple fix but one that returned the trike back to its original power. As we ran it on the rolling road the trike revved through smoothly and made 38bhp. We even reached 70mph, which the owner had never seen in his time of owning the trike. Out on the road test the trike felt like new and we even overtook a lorry on the motorway. Again this was something the owner had never been able to do whilst owning the trike.