1986 Suzuki GSX-R750G

Bertie Simmonds
April 25, 2017

Q: I recently purchased a 1986 GSX R750G. It is a Jap import, but I have read in your magazine that these bike are restricted to 75bhp and it certainly does not feel as quick as it should be, Where are the restrictions in this bike and how can it be derestricted back to its natural 100bhp?

A: There is quite a bit of debate on this subject but as far as I can glean, the restriction is based around two things. The speed has been limited to 180kph (i.e. the limit of the markings on the Japanese market speedometer) and this is done electrically at the speedometer. You might need to check your wiring against a wiring diagram for the UK specification model to see what differences there are and try cutting any extra wires as an experiment. The other restriction is by limiting the diameter of the exhaust pipes near the exhaust ports, and these can be ground out to more suitable dimensions.

About the Author

Bertie Simmonds

As a child Bertie (well, Robert back then… blame his sister for the nickname) was exposed to motorcycles thanks to his uncles. They would show up at his house with a lovely lady as pillion throughout the 1970s and 1980s. After a naughty time on field bikes (it’s what we did back then) Bertie passed his test in the early 1990s and became a reporter for MCN in 1995, moving to the sports desk and covering World Superbikes in 1996. With a change to Bike Magazine in 1997, he stayed until 2000 as news, features and road test editor. Moving into PR with Cosworth, Bert was bored with cars and returned to bikes in 2001 with Two Wheels Only, becoming editor in 2002 and leaving to be freelance at the end of 2004. With almost a decade freelancing, Bertie joined Mortons in 2013 and became editor of Classic Motorcycle Mechanics, a post he’s desperately clung to, to this day. And no, he’s never had a pretty girl on the back of his bike.

Share this article