KTM Setup Thread...
I've got a bunch of time to kill, so I figured I'd get started on a thread I've been meaning to do for a while.
In my experience, KTM's in general are very responsive to subtle changes in setup. I have only owned 2-stroke 300's, but in my time with these (excellent!) bikes, I've picked up a few things that I think are helpful. Much of this will apply to any KTM, some of it is specific to the 2T's.
Please chime in with your own suggestions... There seem to be a fair number of KTM off-road bikes around!
For lack of any better ideas, I'll just start at the front and work my way back, beginning with generic stuff and then a seperate reply for 2T's.
In my experience, the front end is extremely fussy about how it is aligned for smooth suspension actuation. The first thing to do is test stiction- on a flat surface, without touching the brakes, lay your palms flat on the handlebars and push down. If the forks are well set up, you should be able to make a very small movement with minimal force. If the front end is sticky, you'll use quite a bit of force for a fairly large movement. If your forks test out alright, great. Most don't.
To fix this, first loosen everything on the front end except the actual axle, including the axle pinch bolts:
the triple pinch bolts (both top and bottom):
and the upper stem nut, and the bolt in the upper triple clamp that grabs the stem:
Now, with everything finger loose, pump the forks through their stroke a few times. You may observe the fork lowers resettling on the axle, and the triples shifting around to bring the forks parallel. This is often necessary after even a low speed tipover, as the handlebars and wheel can put a lot of torque on the forks in the triples.
Once things are better aligned, start by tightening the axle pinches, then the upper triple pinches and stem, then the lower triple. On the lower triple, overtightening will cause binding in the fork, so be very sparing with torque. I get them both touching, then give them 1/8th turn increments alternately between bolts until there's just enough tension I don't think they will fall out.
If you've done this right, you should be able to get very small suspension movement from the test outlined earlier. The 03 and newer front end is MUCH better than the 00-02 41mm forks as far as alignment goes- that bigger, teflon coated axle really helps.
Other fork setup:
- Bleed the forks regularly via the phillips on top. The WP's build up a lot of pressure fairly quickly, and I believe that frequent bleeding gives better fork action as well as improving fork seal life. My 03 is still on original seals.
- If the seals do start to weep a bit, work the dust wipers down with a flatblade, and then run a piece of paper around inside the fork seal. Often, the seals weap if the wiper edge gets twisted, and you can fix that with paper without replacing the seals. When you reinstall the dust wipers, put a thin line of white lithium grease above the wiper. This seems to help keep outside stuff where it belongs.
- Change the fork oil fairly often. It's a 20-30 minute job, and you'll get all kinds of crap out of your valving that will make the bushings last longer and the action more compliant. Remember to set the oil level between 110 and 130 mm with no oil between the inner and outer walls (pump the outer up and down after bleeding the cartridge to ensure that no oil is between the outer, female slider and the inner, male slider).
And that's about all I can think of for forks.
- The KTM pads seem to give good performance and wear reasonably well. As a bonus, when you get them hot, you can make them howl like banshees, which is enjoyable in a race for disorienting and passing others.
- Zip tie the brake lever back if you've been using the brakes hard, and any accumlated air will bleed out on it's own overnight.
- The spokes on 01's and 02's suck, as has been frequently discussed. My 03 has had no issues.
- For mixed terrain and durability, I really like the Kenda Millville front. It's cheap, lasts pretty well, and is awesome in both sand and rocks. I also like the Dunlop 755 front, the Michelin M12 and the Bridgestone 401. The only tire I've disliked was the Pirelli MT44, and not because it performed badly but because I ripped all the side knobs off it in short order.
Can't think what else on the front end. Next installment: chassis bulletproofing, generic to KTM off-road bikes, then 2-stroke specific, then rear end.
Great write up, Neduro!
Minor data point: LC4 Adventures have had these 48 mm WP forks since '01. Same part number for the axle, I believe.
Part 2: Chassis Bulletproofing
I don't know exactly what of this will translate to the LC4's, but most of it applies to the RFS 4T's and all of it to the 2T's...
Skidplate: The Devol skidplate is far and away the one of choice for the 2T's. Rather than micky-mouse hooks, it uses a piece of flatbar across the framerails with holes drilled (sort of visible below). Seems to stay in place very well, provides good protection, and not too pricey. :thumb
Stay away from both the KTM hardparts plate, and the enduro engineering plate. Both are undersized and made from thin material.
Enduro Engineering sells a kit to relocate the CDI out of harms way, under the tank. In it's original position on the frame near the steering head, it is vulnerable to crash damage in odd scenarios, and if the steering stop bolt ever vibrates out, the forks will hit it and ruin it. And putting it under the tank allows you to dial in some more steering lock. Money well spent.
The front brake line will cut into the clutch line, if given the chance.
My solution is low tech- I just put some fuel line around the clutch line and keep an eye on it.
I also wrap the brake line/odo wires in some of that expandable plastic sheath (visible in the photo above) to protect against chafing. Seems to work.
The shock location on the 2003/2004 bikes flat out sucks:
My boot rubs heavily enough to wear through the shock body in about 1500 miles. GRRRRR! Had to buy a new shock:
On the plus side, I got one off Mike Lafferty's bike right when he broke himself, and it's magic. Whatever special sauce they use seems to have made it into this thing... solution is to buy the e-line carbon guard for $40. No issues since installing one.
Speaking of e-line, their carbon pipe guards are the best solution I've found. I've tried both Pro Circuit and FMF Gnarly pipes, and prefer stock for the way it makes power... and the e-line guard has protected it in some horrific hits. :thumb
Now for a big one. All KTM's I've seen have a thermostat housing right behind the radiators like this:
On this bike, it hasn't done much, but in many cases the corner will rub into the radiator over time and cause leakage. My solution is to safety wire it back to the tank mounting point, so that it just can't QUITE touch. This is worth a look, on both 2 and 4 strokes!
Speaking of, that plastic "Y" fitting on top of the motor is a weak link. Whenever you do a top end, inspect it for cracks or other signs of wear. If it breaks, you'll have no coolant in a hurry and it's a good way to ruin your motor and your day.
The kickstand is another weak point, in that it is not designed to bear any load more than the bike, and it's easy to break the mounting bolt.
My suggestions: loctite the bolt, and keep an eye that it stays tight. If it loosens, you'll break it off very easily. Put tri-flow (bicycle teflon lube) on the kickstand to keep the action free- one application will last quite a while. Finally, use the little rubber strap provided to hold the kickstand up when not in use- my experience has been that the bolt will not tend to loosen if the kickstand is supported by the strap.
Unlike Jap bikes, my KTM swingarm pivots have always been reasonably well greased from the factory. The Heim Joint and the upper shock mount needle bearing will eventually wear out, but the original KTM parts seem to last well and are not unreasonably priced IMHO. On very high mileage bikes, the mudflap hanging down in front of the rear wheel will begin to eat into the swingarm aluminum- several companies make guards to help prevent this.
The Enduro Engineering Sharkfin (brake disk guard) is cheap and effective. Good insurance for the rear disk. The bolts like to vibrate out, so loctite them (or weld the bastard on if you want to be sure...).
Can't think what else for the chassis... Dirtrider will no doubt be correcting me here shortly...
I could be wrong, but I thought the 01/02 SX's that had 48mm forks had the little axle, and it wasn't until 03 that anything got the bigger axle. But maybe that's just MX bikes, or maybe I'm just flat wrong. In any case, a minor point, except when buying wheels...
Fork oil change
Nice overview of "things to stare at". :thumb
If you have the time, and want to put out the effort, can I suggest a more detailed guide or outline of a "quick and easy" fork oil change? I think that quite a few folks would benefit from one. :nod
Besides, there may be a new orange beast in my garage very soon... :wink:
Nice thread, btw. I'm gonna share it with my 300EXC flogging bud. He loves 'em and here's his latest..
He's a big guy, REALLY fast, and has everything valved & sprung to suit. A real setup and maintenance freak. Even cleans it madly in between the dirt/mud dunkings. :D Anyway, what a great motorcycle.
Another bud has it really bad. Among other brands, he owns a 200exc, 450exc & Duke. You never know what he's gonna show up on, but he's another excellent enduro rider who's ate up with the details of good setup. You'd love a garage session over here!
FWIW, I think I'd prefer the 200 over all of 'em for tight woods, just 'cause I'm least likely to get maimed with 100 less cc. :rofl
I'm sure I'd enjoy a garage session down there as well. You guys ever come to the TESCEC Enduros? I hit some of the North Texas ones...
2 stroke specific stuff...
First, let me start with why ride a 2-stroke, and why a 300 in particular.
1) Reliability and durability and cost of running: To my knowledge, there is no other bike that is as performance oriented as the KTM 2-strokes (light weight, premium components) that has anywhere near the reliability they show. I ride a lot, and I ride pretty hard, and they take it like they were designed for it (because they were). No monkeying around with unrefined systems, the bottom ends last forever (a friend, Fast with a capital F, has a 2000 380 e/xc that he rides as much as I ride mine. He's done a top end a year and has yet to see the inside of the bottom end).
Doing a top end on the 2-strokes costs about $150-250, depending on OEM or aftermarket piston, and takes a couple of hours (or 20 minutes if you are an ISDE racer). The modern 4-strokes, especially those from Japan, have a shorter top-end life than the KTM's do, and the job costs at least $500. Not to mention, if something goes wrong on the 4-strokes, you're into $1500 by the time you start replacing everything that needs it... 2-strokes have about 4 moving parts, so it's pretty hard to break them.
So, given that brake pads, chains/sprockets/tires are the same as anything else, the overall cost of owning and racing a 2T KTM is basically cheaper than anything else out there. The 2T Jap MX bikes are just not as durable- trannies, bottom ends, and top ends are all underbuilt compared to the KTM stuff (though certainly workable).
2) Weight and rotating mass: The 2 strokes are light and they feel it. The 4 strokes are heavier and try to disguise it... but what they can't disguise is all that rotating mass. Step back and forth from a 2 stroke to a 4, and you'll instantly feel the difference of having a several pound gyro (crank and valvetrain) spinning at reasonable RPM's.
3) It's damn fun. It is zippy and playful and makes you feel like a hero, even when you are a gear high or a gear low, even when you miss the apex and have to pick it up with your foot, even when you stall it. It starts easily, always, and the motor can be ridden aggressively at the start of a race or chilled out at the end of a long day of trailriding, and it's happy either way.
Now then, on to setup:
The weak point of the motor, for sure, is the exhaust mounting. It's mickey mouse and it's basically impossible to avoid all leakage:
There are a couple of tricks to minimizing it, though:
- Clean everything really well with carb cleaner, which is the only thing that cuts spooge very well.
- Check pipe alignment- if one side is cocked out, it will never mate well. Use a broom handle inserted into the pipe to "convince" it to go straight.
- Line the pipe with hi-temp RTV sealant before assembly. Watch it come out the exhaust for the next 2 rides. :D
- Double spring it if you can't get it hung quite right.
As I said earlier, I prefer the stock pipe on the 00-03 300 motor to any alternative I've found. And the eline pipe guard is the ticket for protecting it.
The stock silencer is good, and when fresh, will test at around 89 dba (which is quiet!). I also have an FMF Q, which is a touch louder... but offers less leverage in the case of an "issue" for tweaking the exhaust system. And I think it looks better. I run them both, and can tell no power difference between them.
Carefully clean the junction between the expansion chamber and the exhaust pipe. Assemble with no sealants or zip ties on the rubber gasket- they don't seem to help. If it is a good fit on both ends, it shouldn't leak. If you have to torque it into place, be prepared to spend some time cleaning. DAMHIK.
The KTM's are unique in coming with a jetting chart. It's conservative, but not overly so. If I have a debate for which box I fit into (it's a temp/elevation matrix), I err to the lean. This will be a good starting point and you won't seize the bike. Some folks like to go to a #7 slide cutaway and run the N85D/E needles, some folks run some of the newer needle tapers... I find that the KTM book gets me close and leaves me confident that I won't blow it up, and that's worth something. Summer jetting for HIGH elevation (8k +) is NOZI/3rd, 40/162, about 1 turn on the A/S. Winter is NOZH/3rd, 45/175, 1 turn. Whenever I rejet (which is a lot) I write what's in there with a sharpie on the side of the float bowl. It'll wash off with gas and it means you never remember wrong and leave summer high elevation jetting in for a winter ride at sea level.
The OEM Mahle Forged Pistons last a long damn time. Wiseco Cast pistons are a bit lighter and rev easier. Note that KTM provides 2 different sizes of cylinders- they are very close, but your original piston will have a "1" or "2" stamped in the head. If you go OEM, get a matching piston. If you go aftermarket, they aren't precise enough to care.
I have been running no-toil products in the air cleaner for a long time with good success. I'm sure the petro stuff would have worked fine too, but no-toil is much nicer to work with.
I have an enduro engineering clutch slave protector. It's got a lot of marks from chain slap. No idea if any of those slaps would have hurt the stock unit... but I'm glad I didn't find out. Another $20 well spent.
The bike comes with a crappy guard between the chain and tire, which falls off shortly after you start riding the bike. Preemptively take it off, and use some silicon to seal the holes so you don't fill your swingarm with water and sand.
Anyway, I'll see ya up there sometime. :nod
Thanks Ned, I had a get off on my bike recently but I didn't know some of the details you posted for truing the front end. I will run this by the bike when I gets a chance! :thumb
I just got your PM as I was in Denver until last night. Awesome thread! As soon as I get caught up on my work, I'll add to it. :deal
Great stuff Ned and others keep it coming. Unfortunately, I have nothing to add to this thread, I can only take. I do have a question though.
I noticed in your photos that your cover has been dented in and it looks like it was creased by the brake lever bolt. This happened to me as well during a spill where the brake lever bent in and rode up creasing my cover almost to the point of going through. I was thinking about grinding down the sharp stuff on the inside of the lever or even welding on a small glider plate (say, a 1 1/2 inch square piece of metal) to the inside of the lever or even sticking a small piece of plastic on the case so the lever would glide on the case instead of going through. Any ideas?
Honestly, it wasn't a problem on either of my 300's, so I haven't put much thought into what to change. Let me consider it.
I'm looking forward to Dirtrider's comments. As someone who rides a lot, is obviously mechanically inclined, and works in a shop and therefore gets to see what goes wrong... I'm interested for what he can add.
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