new guy on the block-KDX200 height? plug?


Jun 18, 2001
I am new to the sport; purchased an '85 KDX 200 2 months ago and love the bike. However, being the rookie I have a couple of basic questions. (1) height of bike. I am 5'9" tall; both toes touch the ground. I have already lowered the bike the half inch or so that the adjustments allow. Almost all the other riders I watch look like they can flat foot their bike with no problem. What is recommended? I cannot find much info on this topic. (2) the bike came with a NGK8ES spark plug and ran fine from day 1. The manual says to use a 9ES and changed it yesterday. Is it my imagination or could it have a little less low end with the 9 plug? another words could the bike have been tuned to the 8? Thanks in advance...


Mar 21, 2000
As far as the seat height goes you could look into cutting down the seat foam. Or better yet get some aftermarket seat foam (less spongy) and cut it down to fit. I also happen to be about 5'9" and touch tip toed when I try to put both feet down however if I just put one down and lean the bike I'm fine. In fact my other bike (RMX 250) is taller then my KDX and I feel just as comfortable on it. Guess what I'm trying to say here is you just may find that once you get used to the bikes height you might regret messing with the seat foam and find yourself adding some more height by adjusting the suspension stiffer.

As far as the plug goes I would go back to the 8 since it works better with your bikes jetting etc. If I understand it right the 9 is a cooler heat range then the 8 and therfore the bike is now runing on the rich side as far as air/fuel mixture for the plug goes.

BTW - I run NGK B8ES in all my 2-stroke bikes and they work just fine :cool:



Oct 1, 2000
First the seat height shouldn't be a problem. I'm 5'8 and I have a 00' which sits higher than and 85. What you should be concerned with is proper sag. If you adjust your suspension so you can sit comfortable you might throw the suspension out of whack making it too soft. I have my rear sag set to 3.75" and others I know use 4". Sag is the distance from your rear axle to a spot on your rear fender without any weight, the bike should be on a stand so the rear tire hangs. Next have someone help you measure the same points with you sitting on your bike with your full weight minus the stand. The difference between the 2 measurements is your sag. The 8ES is the correct plug and if you are jetted properly you may nevr foul one.

David Trustrum

Jan 25, 2001
There are heaps of threads on this subject, many are in different forums. I too am 5’9” but seem to have slightly short legs. Though it seems I am not as short as I thought. I cut the seat foam down & am wondering if I am beginning to regret it. It is great when dabbing around in the tight slippery stuff, but it’s also nice not to have to stand up so far when you want to get up if you see what I mean.

Both these chaps have good advise, set your sag & try it out for a few rides. My other fav idea is get a decent cobbler to rebuild your boots with a spacer or a second sole which will give you an extra ½ inch.


Oct 14, 1999
Hertz or Avis (not exactly?)

Sag is the distance from your rear axle to a spot on your rear fender without any weight

Not exactly. With ONLY the weight of the bike, the amount it drops is 'free sag'. Maybe that's what you mean by 'without any weight' ?

Next have someone help you measure the same points with you sitting on your bike with your full weight minus the stand. The difference between the 2 measurements is your sag

Not exactly. It's not the difference between the two (loaded sag<->free sag) but fully loaded sag <-> NO sag (topped out)= race sag.

Sometimes free sag is important..sometimes not. You can use it to determine if your shock spring is right for your weight (the race sag already being correctly set). Jeremy says that measuring free sag on a bike with his suspension is irrelevant.

So...measure the topped out distance (no load on the suspension..from the axle to a straight-up postion to the fender for example), then the distance with the rider on the bike..full gear. That difference is 'race sag'...or commonly just called plain 'sag'.

Then check the free sag. If there is < 3/4" or none..your spring is too soft. If there is a large amount..your spring is too stiff (for your weight).

As far as the point of this height:

You'll find you get used to it for one thing..flat out LIKE it, too! I'd hold off shaving your seat foam until you get some more time on it. The more you get used to it, the more you ride, the more you'll find your feet are on the pegs (where they should be, anyway), and seat height becomes less of an issue.

That said...a set of Devol pull rods (dog bones) will lower the bike about 1/2" in the 'long' setting. That from a newer series standpoint. Any lengthening of the pull rods will lower the bike. Will also increase the trail angle. That will 'slow' the low speed handling somewhat..but will also stabilize the high speed handling.
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Sep 7, 2000
I have only been riding for about one year but I find that I don't want my feet to sit flat on the ground. The reason being that when I make tight turns I find myself wanting to put my foot down, which only leads to me and my bike landing in a tangled mess.

I had my bike lowered so I could put my feet down relatively flat but raised it back up for this reason. I think a good height is so thsat the balls of your feet are firmy in contact with the ground but your heels aren't which leads to better habit formation.

I don't know if this is the generally preferred situation but it works for me.:cool:
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