20 Things You Should Know About: KTM’s 950/990

This entry is part 43 of 24 in the series Adventure Rider Issue #3

The LC8 motor first appeared in 2003 in the KTM 950 Adventure. The same powerplant went on to power the 950SE and the fuel-injected 990 Adventure. The motor hasn’t really undergone many changes despite the model designations, and this applies to frames as well.KTM dealer and keen 950/990 rider and competitor Craig Hartley outlined a few of the main traits on the tried-and-trusted Adventures.

Craig Hartley knows how to build and ride a reliable, competitive 950/990.

Most of the habits of both the 950 and 990 are very similar apart from some minor fuelinjection traits on the 990. These traits aren’t a big problem once understood, so here are a few things that may help owners to better understand their machines.

The 950 and 990 have a great deal in common. They’re both proven performers.

1. Valves: On the older 950s, valve adjustment and wear was more frequent due to a more aggressive cam-lobe profile, so it’s been common to replace valves on a 950 in 35,000km or so, although I’ve seen some with up to 70,000km. The 990 engine has a kinder cam profile which is easier on the valves. That means that even though you still check valve adjustment every 15,000km, the adjustment is minimal and it’s common to see 990 engines with original valves still within adjustable operating specifications with 90,000km or even 120,000km on the clock. Basically, we’ve never had to fit valves to a 990, so they could last indefinitely.

2. Waterpump seals: The LC8 motor has a couple of probably unintentional built-in alarm systems to warn when there are waterpump issues. The temperature gauge won’t always tell the story of looming problems, but the warning signs on many occasions are obvious. If the oil-pressure light flickers on/off at idle, the most obvious problem will be that the waterpump seal is leaking coolant into the engine oil, which then clogs the oil filter and limits oil pressure. A quick fix to get you home, or to a service centre, can be to remove the oil filter and preferably replace it. If there’s no replacement available, wash the coolant off with petrol poured over the outside. Remember this is the oil filter and it’s critical it stays spotless. The other tell-tale sign is lots of cam-chain noise at idle. This is due to the oil-pressure operated camchain tensioners having low oil pressure. Once the oil filter is partially clogged, the oil pressure is low at idle and the cam-chain tensioners don’t work as they’re designed to, allowing the cam chains to rattle. I think it’s good to replace waterpump seals and bearings at the 30,000km or 37,000km service to be safe. On really long trips I carry a spare oil filter and waterpump kit and Blue Max Loctite to seal or repair gaskets, be it for myself or someone else.

3. Service intervals: Basic services are recommended every 7,500km. Major services (with valve adjustment) every 15,000km. Depending on use, some people change the oil every 5,000km.

4. Prefilters are a great idea for more reasons than just saving your air cleaner. The dirty air is directed into the airbox below the filter, before drawing up through the filter then into the venturis. This means you have a mass of unfiltered air circulating around the throttle-shaft assemblies and linkages, and this can lead to wear in both these areas. In extreme cases this can allow air and dust to be sucked through the worn throttle shafts, and that can mean premature engine wear. It can be bad enough that the bike can’t be tuned, especially for smooth idling and backfiring on deceleration. Obviously the other benefit to running prefilters is the prefilter can be washed and lightly oiled pretty much anywhere in Australia.

5. Fork springs on all 950 and 990 Adventures are always too soft and should be replaced to get the optimum balance and performance from the suspension. My own bikes always have large fuel tanks, tank bag, full saddlebags and a swag, and once I have heavier fork springs I can always get the suspension working to a good level by controlling things just with the compression and rebound damping and spring-preload adjustment.The shock spring in all standard ABS, S and R models is more than adequate for 99 per cent of riders.

6. Steering-head bearings: Another serviceable item, especially for adventure bikes that have done a lot of back-road riding. I find that usually about 35,000km is all I get out of them before they start to get the old straight-line notch.

P clip holding the brake line on the top-rear of the fork protector.

7. Fuel-injection filters: The main problem encountered with fuel injection is the “teabag” 12-micron filter getting blocked. The symptoms are a motor with no power, that won’t rev over 3000rpm to 4000rpm, and that could cut out for no reason and restart but still not be well.

There are two filters in the fuelinjection system of the 990, and for the record the same pump and filter system is in the 1190. The first filter is the finest one that picks up the small particles in our fuel. This doesn’t necessarily relate to dirty fuel from the service station, it’s just the quality of the fuel we have in Australia and some other countries. The larger, round filter inside the pump doesn’t cause problems and from memory is a 32-micron filter.

I really don’t know why it’s even in there.

Once again I’d recommend fitting a new teabag filter every 15,000km.

If this filter stops you in the middle of Australia all is not lost. Simply remove the fuel pump, pull the filter out and wash it in water with detergent while kneading it through your fingers to work the fine particles out. Use compressed air if available, but if not, simply dry it out and you’ll get it good enough for the bike to run again.

The other option that definitely works is the KAA Purge Unit. It works by sending a reverse current of power to the fuel pump for 1.5 seconds after the ignition is turned off. This flushes the fine particles from the 12-micron filter. We know this works because of a great deal of field testing.

We also remove the original one-way valve in the fuel pump and put an external one-way valve just outside the fuel pump in the fuel line to the injector, giving more fuel to reverseflush the filter.

You may be asking, “Why push all the stuff back into the tank only for it to create the problem again?” The answer to this has a lot to do with how fine the particles are. It appears that in small doses these particles in our fuel don’t amount to anything, but after large volumes of fuel have passed through a small, fine filter, these small, black particles seem to join together to form a mat that doesn’t allow fuel to pass in sufficient quantity. If you want a better explanation you’d be best to contact a industrial chemist.

8. The front rims on large adventure bikes have been known to get the odd dent. For the first 70,000km of use on my KTM 950, and this included when I rode the Australian Safari on it, I ran Bridgestone ultra-heavy-duty tubes at 18psi. I had great traction (for a 100-horsepower, 200kg bike), but I did dent a few front rims. It does appear the same combination, except with 24psi to 26psi makes the rims last longer. (Or could it be the new glasses I now wear when I ride).

On another note we’ve fitted many Excel Takasago 21 X 1.6 front rims in preference to the original 2.15 size. I believe, especially for dirt work, that the narrow rim makes the profile of the knobby front tyre more suited for what they’re designed to do. Our favourite front tyre for the large adventure bikes is the Michelin Star Cross HP4, maybe not the best for carving up the bitumen twisties in the high country, but for general longevity and a great feel on the dirt.

9. ABS: If you find yourself with an ABS-model Adventure and you’re continually forgetting to switch off the ABS, a simple fix is to follow the ABS power cable from the rear calliper up to the ABS unit in the toolbox under the seat and disconnect that white plug. That will bring a fault code up on the dashboard and you’ll have no ABS braking.

10. Rear subframe: I have a lot of mates all over Australia who have done tens of thousands of kilometres on 950/990 Adventures. These people travel with the likes of Andy Strapz Bags mounted forward on saddlebag racks and a compact swag or bag of camping gear on the rear carrier. I cannot recall anybody who loads their bike like this who has broken a rear subframe. These bikes don’t have a problem with the subframe unless it’s overloaded. A good rule of thumb is up to approximately eight kilograms per bag or swag.

11. The two-stage ignition plug is positioned between the rear spark plug and under-seat toolbox on the 950/990 Adventure. It’s a single plug wire that, when disconnected, retards the ignition so as to avoid pinging when only low-octane fuel is available.This plug can be run in the disconnected position continually if necessary. Low-octane fuel and high-speed can cause severe engine damage. Trust me, I’ve seen the results.

12. Checking oil: This simple task can sometimes be a little confusing. Very often we’ve put the bike on the centrestand and run it for several minutes, only to find the oil level is either too low or too high. If the bike hasn’t had a history of using oil, run the motor for another three or four minutes to operating temperature. Usually you’ll get a closer reading second time around.
The correct reading is with the dipstick screwed in. To give yourself a bit of leeway, and taking into account they may use 100ml or so in an oil change, on long trips of 5000km to 7000km I’ll leave home with the oil tank full with the dipstick sitting on the thread, not screwed in.

The trip master switch can make handling the gauge info a lot easier.

13. Clutch bolts: Another minorservice schedule job is to check the six bolts on the clutch basket. Simply lay the bike on its left side, pull the pin out of the rear brake pedal, and remove the clutch-basket cover.
Another hint for the clutch is that it has 12 fibre clutch plates, the very inside one is a smaller plate than the other 11. If your clutch is getting a bit lazy there’s a very good chance that if you replace the small inner one, it’ll give the clutch a new lease of life. Duct tape one under your seat. If you’re away from home and don’t have the spare, try placing some washers under the six spring-retaining bolts.

14. Clutch slave cylinder: You know how when you’re working on your bike, people just have to walk up and pull the clutch lever or the brake lever in? Well, if you happen to have your clutch slave cylinder off doing a front sprocket change and this happens, you’ll be up for a new clutch slave cylinder. It’ll blow the circlip and retaining shoulder out of the cylinder. I know, it’s happened to me.

15. Fork bushes: Large-capacity adventure bikes, especially the 950/990 KTMs, just love chewing up mongrel roads at high-speed. This is all good, but you do pay a price. An example is the steering-head bearings, as mentioned earlier. It pays to get someone to check the fork bushes, probably at around the 50,000km to 70,000km mark. It’s not that the forks will fall off or anything, but the frequency of leaking fork seals and more wear on the fork legs could create problems later on.

16. Power outlets: Behind the dashboard are two power outlets named Access 1 and Access 2. These are perfect for GPS, some heated grips and other power needs. These are in all KTM trail and adventure bikes.

17. Trip master switch: The fitting of a trip master switch beside your left thumb is a great way to access the different modes on your speedo without taking your hands off the ’bars. Trip one and two, time, odometer and switching off the fuelreserve mode are all useful options for this switch. Trip two can also be adjusted up and down with the switch, which is handy if you’re using a route sheet. It can be a good accessory if your speedo mode button stops working as well.

18. Best fork protectors: For many years we’ve been annoyed by not being able to buy genuine fork protectors to suit the 950/990 when fitting high guards. The latest idea we’ve tried is to trim the guard off of the original front guard/fork protectors and use these for our fork protectors. We simply run the brake cables to the outside of the forks and use an insulated P clip at the top rear of the fork protector to hold the brake line.

19. ’Bar risers: All larger bikes respond well to being ridden standing up, so for most people ’bar risers are a great idea.

20. Wide footpegs: Once again, due to the amount of standing up you can do on this bike, the fitting of footpeg extensions, or even lower and wider ’pegs like the Fastway Adventures, is a great idea. For many people when standing on the ’pegs they’ll find they have only half a foot on the standard peg.

Series Navigation<< Reader’s Ride: The Flinders Ranges, SA10 Minutes With: Sam Sunderland >>