Tighter turning

[MikNY]

Refreshed my 94 KDX 250 last year and finally have time to start putting some miles back on it(owned it since new). There are 4miles of wide reasonbly high speed trails on my property and the bike does ok here as it's pretty stable and makes decent power but recently we have set up some new single track and trying to get the old girl to turn a little tighter. I've read enough on here to realize these aren't the greatest turning bikes to begin with and the forks are a weak link, they may get swapped eventually but trying to get the most from my current hardware. They forks have new seals and fresh oil. I weigh about 190, any help on a starting point would be awesome. My plan is to move the forks up in the clamps 1/8th and drop the comp dampening to full soft and start working from there. Tires are set at 9psi and are in good shape. The trails are tight wet woods with lots of roots and logs. Am I heading in the right direction as a starting point?
Daughters boyfriend races a KTM 200exc hence the desire to pick up my pace, I have no delusions of grandeur here just hoping to at least give the kid a hard time and make him work a little to stay in front haha. The fathers here will understand...
Mike

[bufftester]

You let your daughter date a guy riding a KTM???? #$^#&$^* lol

All kidding aside, the first step is to get the suspension dialed in and balanced for your weight. Not sure on the 250 , but the later 200/220s were horribly unbalanced (front spring good for 140 lb rider, rear for 190ish). Race tech has a decent calculator to get the spring rates dialed. If new springs are out of the equation, then dropping the clamps a little will quicken the steering (steeper head angle), but at the loss of some high speed stability. Remember to set your sag before each change (may need to play with preload spacers up front). Then ride a bunch, change one thing, ride some more, change one thing, ride some more. Suspension tuning is one of those process items. Damping/oil/shim stack configs will help keep the front end planted and working, but not necessarily turn tighter (thats a function of head angle/wheelbase). Riding technique can also assist. As a father I totally understand, I ride a GSX-R road bike and the daughter's BF rides a Yama If all else fails you can always let some air out of his tires, turn his clickers to odd settings, pull his sparkplug boot partially off...... lol

[Goofaroo]

You need to adjust your throttle position. Everything else is just fluff.

[diymirage]

You need to adjust your throttle position. Everything else is just fluff.

yup, best way to make these bikes turn tighter is to get on the gas a little bit earlier on in the turn and steer with the throttle
when I first changed my KDX to USD forks I felt like I lost a LOT of turning radius because the forks are just that much wider and limit how far you can actually turn the handle bars before the tubes hit the tank

I really had to learn to steer with the throttle to make up for that

[MikNY]

With how wet the trails have been sliding the rear end has been no problem...the sliding of the front end has pretty much sucked though! Getting old stinks!

[kawagumby]

I agree with bufftester, the only way you can improve the steering (all other things being equal, i.e., rider skill, tires, etc...) is to get the suspension settings dialed-in including sag.
If you have confidence in the front forks, you can weight them heavier in a turn and do about anything you want. With regard to the forks settings, make sure you are getting full travel with the oil height setting. Don't go too soft with fork compression, only enough to get rid of initial harshness in the travel. Make sure you have springs that are firm enough for a 190 lb rider, I'm thinking most bikes are not going to have stock springs stiff enough for that weight. Make sure the rebound (if it has rebound settings) aren't too loose, meaning too much spring-back after a hit. I like to use water bars or other small jumps to dial the settings in so as to stay level during the hit. If you set up the front too soft (soft springs, soft compression damping) you will have too much dive resulting not enough control and you'll end up plowing in too much and losing front traction - the opposite of what you need.

[bufftester]

I agree with bufftester, the only way you can improve the steering (all other things being equal, i.e., rider skill, tires, etc...) is to get the suspension settings dialed-in including sag.
If you have confidence in the front forks, you can weight them heavier in a turn and do about anything you want. With regard to the forks settings, make sure you are getting full travel with the oil height setting. Don't go too soft with fork compression, only enough to get rid of initial harshness in the travel. Make sure you have springs that are firm enough for a 190 lb rider, I'm thinking most bikes are not going to have stock springs stiff enough for that weight. Make sure the rebound (if it has rebound settings) aren't too loose, meaning too much spring-back after a hit. I like to use water bars or other small jumps to dial the settings in so as to stay level during the hit. If you set up the front too soft (soft springs, soft compression damping) you will have too much dive resulting not enough control and you'll end up plowing in too much and losing front traction - the opposite of what you need.

+1 good info there

[MikNY]

Thank you, def appreciate the help. Heading out now to test the effects of raising the forks in the clamps.

[MikNY]

Holy crap! Moving the forks up just a bit really changes the feel of the front end. I feel like I can load the front end better coming into a tight turn, nice change.
Question, on the carb should the air screw be set 1.5 turns out from seated? I noticed mine was seated down snug and since I have never touched it must have been delivered this way. The manual says 1.5 turns from seated while adjusting the idle speed but doesn't state if it should be reseated or left at 1.5 out after setting the idle.

[Julien D]

The airscrew must be adjusted for best throttle response. The amount of turns is not relevant. Fully seated, the bike should not want to idle unless you have an air leak somewhere to off-set it.

I would NOT recommend going full soft on the compression adjusters and riding at any sort of speed.

[bufftester]

Yeah, a seated air screw is not right. Make sure you have no air leaks (intake boot, reed block are usual culprits) , a thoroughly clean carb, filter, new plug, and run through the jetting procedure.

I would NOT recommend going full soft on the compression adjusters and riding at any sort of speed.

+1
Best way is to start at middle range (i.e.: if it takes 16 clicks to go from full soft to full firm then start around 8 or 9) and then test by changing 1 click at a time up and down and riding. I routinely go from riding desert to tight woods and back, and have found the best (for me) settings for each and have them written down (I even used a sharpie to put them on my frame, though now I am reworking them since building the hybrid). Don't forget that what you do to one end can affect the other, so you want to work front and rear and aim for best response for you in your particular terrain. As I said ealier, its a process thing, so if you have easy access to the same riding area it is helpful (which it sounds like you do).

[MikNY]

Couple pics from yesterday

Sent from my C771 using Tapatalk 2

[sarrant]

Man, that's a clean old bike. Nice.

[MikNY]

Thanks! It has def aged better than its owner haha. Its got the usual marks, nicks, and scratches but still photographs well.

[Julien D]

Great example of a 250. Thanks for sharing!

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[rbates9]

Very nice looking bike! But it might be time to ditch those dust busters and get some bark busters. Your hands will thank you!

[MikNY]

RB, Haha youre not kidding, never really understood the point of the "dust-busters".

Buff, I am lucky enough to own the riding area so I have been using the same section of trail to judge the affects of my changes.

Today will be a work day, youngest wants a racetrack for her mini SxS. We set up courses where her track is inside of a larger track and roughly half the length, this allows us to race 10/10s and be pretty close at the finish. We have an RZR and a mini version of it modded out to work pretty well, by 9 she had a pretty good understanding of countersteering, threshold braking, and general vehicle dynamics. She will not be a typical teenage distracted driver... Seeing your kid with total "raceface" while your both crossing the finsh line sideways with your hair on fire is awesome!

If I can complete the track today I can get back into my KDX testing tomorrow. Gonna soften the comp dampening a bit and see if it helps with the deflection. The KDX has always deflected off of roots, rocks, and logs where on the same trail my XR650 tracks straight. The XR has conventional forks and a very flexable frame, guess it just absorbs it better in those situations.

[Goofaroo]

If I can complete the track today I can get back into my KDX testing tomorrow. Gonna soften the comp dampening a bit and see if it helps with the deflection. The KDX has always deflected off of roots, rocks, and logs where on the same trail my XR650 tracks straight. The XR has conventional forks and a very flexable frame, guess it just absorbs it better in those situations.

Your XR also is a much heavier bike which certainly helps make the ride more supple. The extra flex in the convential forks also helps considerably.

I run 2.5 wt oil in my XR350 with stiffer springs to accomodate my weight and about an inch of static sag. It is a fantastic set-up. I would suggest trying the 2.5 wt oil in your USD forks. They'll never be as plush as the conventional forks on your XR but that might help with the deflection. If that doesn't work you might have to modify the valving. Also keep in mind that if you get it soft enough for the roots and rocks you might need more spring rate to prevent harsh bottoming. Everything is a trade-off.

I don't know much about the 250 but I would guess that Kawasaki put the USD fork and the extra 50ccs to affer it as a desert/cross country/scramble bike. At high speed across the desert the USD fork probably works pretty well but for tight woods with roots and erosion, it just won't perform like a conventional fork but I bet you can find a combination that works pretty well.

[MikNY]

Well, didnt get the track finished, anyone with an old tractor will understand why especialy since mine is Russian. The old girls needs a little love before she puts out haha, after the tlc she moved many yards of dirt into the field that will become part of the track.

Guessing about the time I get the KDX suspension working in the woods I will get the field track finished and have to start over...life!

[rbates9]

Belarus?