I test drove a 06 1800 Gw trike. 1st. 1800 i have ridden, always had 1500. It had a whine in engine that changed with RPM. Was loud when cold. After 10 - 15 minutes it was only noticable when stopped at light. Never heard this on my 1500. The 1800 has a timing chain not a belt. Was wondering if that could be the noise.