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.