The 2016 500 EXC should have be sprung as standard with 4.6 springs in the forks and a 7.2kg spring on the shock. The previous owner must have been a big guy, as my used model came fitted with 5.0 springs in the front, and the heaviest rear spring I ever seen on the shock. These were way too heavy for me, and are being changed back to standard spring weights.
I weigh about 75kg, maybe 85kg in my riding gear, and I’ll be carrying luggage. Probably 20kg or so strapped over the rear subframe. The front will be fitted with a KTM powerparts tank that can hold 19 litres of fuel, and petrol weighs in or around 700grams/litre, so the 19 litre tank, when full, should hold around 7kg more weight than what the stock 9 litre tank holds.
Adding it all up, myself, in riding gear, with luggage and fuel, we’re looking at around 115 – 120kg of total weight on the bike, assuming a half tank of fuel. The additional weight will be biased slightly towards the rear so I may need to increase the shock spring rate to take account of that, but might get away with leaving the front alone? We’ll experiment with spring rates and see how we get on.
Every time I look for spring rates, I keep coming back to Slavens Racing spring charts. They’re good charts and are definitely worth a look if you’re interested in exploring spring rates for your bike.
Completely separate to setup however, is suspension maintenance. Having the right amount of oil, the right air gap, good bushes and seals etc..
Depending on the type of suspension on your bike, you may need different tools to service it. A large adjustable spanner is handy for opening the top cap, but again that depends on what you’re using.
My WP4CS needs a pin spanner to open the top cap, and a 17mm spindle key to open the bottom. A 19mm spanner is also needed to separate the cap from the inner stack.
A seal driver might come in handy too, and these are available in various sizes – 43mm / 45mm / 48mm. What you’ll need depends on your bike model and it’s suspension. You can probably do without it, but having the right tools makes the job so much easier.