Join Date: Jun 2013
Location: south of England
Motorcycle: GSXR1186N mainly, plus a few others I've bought over the years
Re: Bike manufacture date
Just noticed your post splinta, you've may have found the answer already, but if not :
Even easier to check the engine number the 1990 'L' model has an R716 engine and 749cc stamped on the barrel - the earlier 1989 'K' engine starts R707 and has 748cc stamped on the barrel. The factory makes the next year's model in the second half of the previous year normally - so most 1990 bikes would've been made in 1989 - the 1988/89 GSXR has the smallest Slingshot frame in height, as the engine for those years had the shortest stroke and therefore shorter barrels.
Another thing to look for is the swingarm - the 1988/89 have very rectangular arms and double nut on a threaded bar type adjuster - if you do a Google search you'll see what I mean.