StevenT

Member
Oct 10, 2005
4
0
I just bought an '05 KX100. I am a 38 year old guy thats 5'6" and 155 lbs. Coming from a CRF230, this thing is feather light and FAST. I ride woods/trails, where some decent jumps have been built in.
Obviously, I am a little outside the expected weight range for this bike and need to modify the suspension. Regarding springs, race-tech's site says that the stockers are .29 forks and 4.7 shock. They recommend .33 and 5.4. Do these seem appropriate?
Also, I would like to avoid the cost/downtime of a revalve and replace springs only. Will spring replacement only be decent?
Thanks for any help you can give!!
 

bikepilot

Member
Nov 12, 2004
804
0
I normally ride a CR250R but my wife has a KX100 which I have to frequently "test ride". She and I are about the same size so I went ahead and set it up for us, I'm 5'10" and 150lbs, doing all woods riding.

I used 0.39kg fork springs from R&D racing and a 5.4kg shock spring from race tech and the more linear rear linkage from R&D which gives +2" rear wheel travel. I'm unsure if the forks were revalved by a previous owner, they feel pretty stock, but who knows. I put 7.5wt oil in them at the low end of the allowable level. Combined with the stiffer springs this gives an amazinly smooth ride though the woods, much smoother than with the previous springs (not sure what they were, I belive they were the .33kg racetech's) which were much too soft and caused to forks to ride too low in the travel.

With the R&D rear link the 5.4kg spring is a tad too soft, with proper race sag the bike has no unladen sag. Still, it works quite well once underway. I belive with the stock linkage the 5.4kg spring would be just about perfect.

I have no idea why racetech recomends .33kg fork springs, these would be way to soft imo.

Yes, spring replacement only is decent, oddly enough the over-damped/under-sprung stock suspension setup works out to be about the right amout of damping for a larger rider with heavier springs.

I also put on a larger rear sprocket, the motor is stroked to 105cc's, stock exhaust (liked it better than aftermarket), advanced ignition timeing a bit (made a big diff in the mid range), home made power-now things (not a huge improvement), 12oz flywheel weight (big improvement in hookup, actually feels like it accelerates faster with the weight, probably due to it getting better traction).

Lastly, be sure to lube all the chassie bearings as they come with little or no grease from the factory. We got our 2003 KX100 last year and the rear suspension bearings were allready rusted. Replaceing them made the suspension action much smoother.

We also have aftermarket top tripple clamps that move the bars up and foward, combined with mini-high bars really opens up the cockpit and allows me to weight the front wheel properly in turns.

I tested the bike quite well at a frinds practice harescramble course. The course is all tight single track with lots of tree roots and bumps. The KX100 was amazing in these conditions. The suspension was super smooth, actually better than my mostly stock CR250. The motor has all the grunt I could ever use (provided you use the clutch to keep the rpm's up) and with the light weight the handling is amazing. I turned quicker laptimes on the 100 than on my CR250R (which I race B class harescrambles on, usually finishing in the top 5).
 

Daddy-O!!!

Member
Nov 18, 2005
8
0
Same here-I also have a 03 RM100(same bike/different color)-I originally bought for my youngest son(11)-He loves the bike-but a little tall for him-I thought I would buy the bike so we could ride together w/300ex we have.Anyway,I am 5'6"-5'7"-175-185 pounds-And I love that little beast-I have added the IMS tank and Pro Circuit pipe and shorty exhaust-I may go w/flywheel weight and instead of going out and buying a KTM125sx - I may weight until son gets more confident and ride the RM.But will probaly get a KTM 250sx-f or the 250 two stroke.I am pleased right now-but it is cold and just had some snow so haven't got to ride much.

Hell-Some may think I am to big for the bike- but I am having a great time w/it and my son right now.I am 35 and had been out of dirtbikes for awhile-I am rambleing-Jeff
 


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