KTM 520 EXC Coolant leak near pump?

I bought a 520 that has been sitting for 6 years from a divorce. It was hardly ridden, maybe 60 miles. Put new plastics on, cleaned up, new tires, chain, sprockets, fork seals, hose lines, gas lines, grips, and carb rebuild. Took it to the shop to have the seal replaced by the water pump since I just wanted another eye on it. The damn pinhole under the water pump still leaks fluid! Other than that this thing can move! CAN YOU SUGGEST SOMETHING? The shop did say the waterpump was pretty rusty.


Thank You!

I think the rusty he's referring to is the camshaft.

Older KTM's had to have the head cap removed to replace water pump seals. Travis at thumper racing has a conversion kit allowing seal change through the WP side plate. If the camshaft surface is pitted, sometimes owners move the seals slightly in the carrier to access unused, and solid camshaft surface for a seal. Unless the carrier and it's 'o' rings are sealed with an anaerobic sealer it could leak. Another leak source is not driving the carrier solid into the mating head surfaces.


Read the comments for more info. If you own a KTM, this is a maintenance item every 4-5K for offroading, much less for guys I know riding them ADV.


Trav's WP vid



Thanks for the reply. You are right on. I spoke with the shop and they said the crank shaft had a bit of pitting on it and is more than likely the cause. I hope it seats soon, I don't want to have to upgrade the crank.


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