Mike Rooney, Liverpool asked us:
I bought my 2025 RA GP350s MT last July. It now has 2000 miles on the clock and has had its first service. My old RA GP300s did 79mph on GPS, so I was looking forward to better performance from the bigger engine. While it handles better and accelerates quicker, the top speed of the new machine is disappointing, showing just 80mph on the clock (about 73mph on GPS?).
I had a dyno run, and it came back at 15hp at 6600 rpm. Your 350 dyno report last month delivered 19hp, and ScooterLab tested a RA TG350 at 81mph (GPS) top speed. Is there something wrong with my scooter? It runs great otherwise, but have other owners had this low top-speed problem?
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Dan’s Scootering Answer:
To answer your question, “Is there something wrong with my scooter?”, my answer is…. I don’t know. Unless I have a scooter in my workshop and test it myself, I find it hard to give a definitive answer, which rules out other variables. What I can tell you, though, is the following two things.…
1) All dynos read differently, so it’s difficult to compare readings done by different operators, on different equipment, under different conditions (weather temp, tyre psi, etc).
2) I am already seeing a little variation on these ‘350’ engines; I’ve seen as low as 19bhp and as high as 21bhp (at the rear wheel)… but never anywhere near the claimed 27bhp (20.5kw) – which I assume is at the crank anyway.
So, yes, your 15bhp does seem a tad low as does the 73mph top speed. But one other thing worth noting is that the Royal Alloy website (www.royal-alloy.co.uk/products/gp-350-mt) claims peak BHP is at 8000rpm on these engines. I note that your graph shows the peak BHP at 6600rpm, which means either the dyno operator did not fully rev out the engine and thus did not see the highest available peak power, or the engine has a fault and would not rev to the claimed peak of 8000rpm. If the engine is not revving out fully, then this would also translate to lower top speed too. So, that might be something worth looking into, until further ‘user data’ becomes more readily available from more owners and other dyno operators.
Let us know how you get on.
Article originally appeared in Scootering Magazine September 2025 issue. To subscribe and grab some Meguiars cleaning freebies visit https://classicmagazines.co.uk/scootering?offer=SCOME2026
