KX100 --> trail bike

[CO Dan]

My 12 year-old, 5'5" daughter has just about outgrown her XR80. I am considering buying a used KX100 and making a lot of mods to it, all aimed at improving the smoothness of the power.

But can this be done succesfully? With porting, a torque pipe and a flywheel weight, can I get this bike to torque around the woods? Are there other mods that would help. Has anyone been there and done that? Any ideas would be great.

BTW, I know from reading the women's forum sporadically that this is a common problem, and I know there are other options, but this is the one I am exploring now.

Other options are:
1) BBR - too many $
2) GG Pampera - too rare, to many $
3) lowered KDX or similar - pretty heavy for a 105 pound girl to pick up
4) TTR125L - already almost too small, in a year definitely too small.
5) 125 4-stroke engine in a KX100 frame - except I'm not a fabricator and probably can't afford the $ to pay someone else.

Thoughts?

Dan

 

[motometal]

I guess it depends on a person's perspective to say just how explosive or smooth the kx100's powerband is.

I don't think it's all bad for a young rider and/or beginner to learn clutch, throttle, and shifter control by riding a bike like this stock. It could be tamed down with a simple throttle limiter or exhaust restrictor.

I used to own a 99kx100 and a 2000 kx125. Both had port work with stock pipes, but the port work didn't really affect the low end in either case. The 100 was much smoother on the bottom and seemed to have better low end power, I figured a good part of this was the lower gearing the bike had.

There is no comparison between a kx100 and a full-race 80 without a power valve...the kx has a much smoother powerband.

The stock pipe and gearing are great for trails. She may want taller bars. The only real weak spot on the bike was the wimpy stock chain, and this may have already been upgraded on the new ones.

Otherwise, my advice would be to save your money on the aftermarket parts and focus on training...she will end up a much better rider in the end.

 

[Okiewan]

Wrong Forum.

 

[Tackett]

i own this bike and i personally love it. It is just the fact that i have outgrown it and i am moving to a 125. They are very quick for a mini. I loved it man. They look pretty sweet with aftermarket N-Style graphics too. I am going to have to sell it. If yall interested email me at mmtackett@kvinet.com

 

[CO Dan]

FWIW, the goal of the engines mods is to avoid having a screamer as much as possible.

I'm thinking about the difference between say a full-race KX250 MXer and a nice woods setup KTM 250 EXC, and I'm shooting for a KTM type power band.

 

[motometal]

I know what you mean. I haven't ridden a brand new KX100, so the powerband may be different now. The '99 I had was actually quite mellow stock, I was just thinking that it might be better overall to learn to ride the bike stock rather than to spend money trying to make the bike into a 1976 KE100. :D

 

[placelast]

Dan: read Eric Gorr's bok/exerpt on the KX100. With some minor work it could become a good woods bike, espeically with a bolt-on flywheel weight. He can do porting to change the screamer tendancies of most engines.

It may still be a bit much compared to a 4-strk, but the suspension & lightness compared to a straight gasser may be worth the effort.

 

[FDR492]

just regear it buddy

 

[JUSTRIDE415]

I ride a cr 80 in the woods great bike

 

[IrishEKU]

The Fly wheel weights sound like a good start. This will make the "HIT" of the power band more manageable. A "Fatty" will extend the bottom end and reduce fouling.....But you may want to check out the new 85 cc's KX. It has the 2 stroke power but in a manageable form that your daughter can handle. If her skill is up to it try the 100 but if she needs to learn the 2 stroker and you can afford it start out with the 85, then move up. Besides the '85 and the 100 have all about the same, just 15 cc's difference.

My .02

Phillip

 

[IrishEKU]

PS. Oike is right......This is the wrong forum.


Ahhh.......Mods?

 

[FritoBandito]

I would go with the KX100 rather than a KX85. If it is a little too tall, just adjust the rear spring tension to lower it and put the front forks up in the clamps to lower it. Then raise it as she grows up.

 

[CO Dan]

To all,

Thanks for the replies, I gather everyone thinks this would work.

Placelast, I'm sorry what book are you talking about?

Anyone have a silencer/spark arrestor to recommend?

Thx,
Dan

 

[placelast]

His performance book; good stuff. I sent you a PM.

 

[kdxDAVE]

If you try a few teeth larger rear sprocket or one less on th e front it should lower the gearing and make it more torquey

 

[CJ Rider]

CO Dan - When are you gonna be in the Colorado Springs/Denver area so your daughter can simply try my bike since it's already got the 10 oz flywheel weight on it? I wish I had PM'd you when I was out your way recently. Poo, I just forgot. Let me know if the next two weekends might work for you if ya want her to try it out. Personally, I found it to be an AWESOME bike for the trails around here and I just LOVE it... and I really wasn't an aggressive rider either at the beginning of this summer when I got it (althought that's kinda changing with the KX). There's really only one way to find out if your daughter might like it. Let's meet so she can ride that KX100! It is just the cooles thing that your daughter rides I think!!! -CJ

 

[motometal]

there is nothing wrong with the stock silencer and pipe, unless they get smashed. The stock exhaust is as good or better than aftermarket, in my opinion. If you just can't stand it and HAVE to blow some money on aftermarket goodies, porting would do more than most other engine mods. Also, if the bike has the wimpy chain setup, beef this up with a kit (this may have been updated by now).

The main difference between the 85 and 100 is bottom to mid power (just like putting a big bore kit in any bike). Since I think you want smooth bottom and mid power, the 100 would probably be a better choice than the 85.

 

[ravencr]

Awesome thread! I'm going to buying my wife a KX100 within the next month, and I'm trying to gather up this exact information for trial use. I'm interested to hear who ya'll recommend buying the folowing parts from:

1) Flywheel Weight - What size should I got with?
2) Full Pipe Guard?
3) Hand guards?
4) Sprockets
5) Chain guide - Is this needed on this bike?
6) Skid Plate - Who makes the best, thickest, strongest one?

Thanks,

Chris

 

[holeshot]

Ive been pondering the same thing for my 12 year old daughter. I had a look at the KX100, and although it's the right size, I'm wondering if the thing will spooge up after many miles of going "putt-putt" on the trail. She only uses 1/3 of the DS80 power right now, and rarely gets out of second gear.

If she had her way, she'd opt for for one of the 85's (they feel and look so cool on the showroom floor), but a quick spin on my 125 and was she cured of the idea of going "full race". In reality, a TTR125LE would suit her riding style better (if she goes too fast, she might break a fingernail). Adults ride these things, don't they?

Of course, if you're raising the next Stefy Bau, your choices would be different. ;)

 

[Motogrl307]

If you jet the bike right it won't spooge up. I play in the woods on my race bike which is set up for wide open and I don't foul any plugs or have any problems. When I ride harescrambles dad adds some more teeth to the back for more bottom without riding the clutch as much. I have my '03 KX100 for sale if interested.

 

[xrkx]

I just got my wife a 04' KX100. I have heard a few of you mention concern about fouling plugs when putting around. My wife has got some good time on hers now, both putting and harder trail riding. It has yet to foul a plug.

 

[23jayhawk]

xrkx, what jetting are you running in SC?

 

[mxchamp85]

From what i've seen about the kx100's they already have very smooth power deliveries, and with personal mods (sprockets, pipes, etc) the power on a kx100 will be 100% manigable for anyone, both expirienced and beginner on trails or on a mx track. The kx100 is the perfect pick in my opinion for the person you described.

 

[ravencr]

From what i've seen about the kx100's they already have very smooth power deliveries, and with personal mods (sprockets, pipes, etc) the power on a kx100 will be 100% manigable for anyone, both expirienced and beginner on trails or on a mx track. The kx100 is the perfect pick in my opinion for the person you described.

I have to agree! I was a little worried about my purchase too, but after equipping it for the trail wth a heavier flywheel weight and a smaller front sprocket, this thing is totally manageable and a blast to ride. My wife loves it, and she rode the TTR125, and it was way too slow.

Chris