KX125/220 hybrid vs upgraded suspension on 95-06 KDX

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KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

I'm not one to leave much of anything stock, but what brings me here again is the curiosity of what a KDX/KX125 hybrid's ride feel is like vs a '95-'06 KDX with upgraded suspension.

I'm really wondering if a KDX/KX125 hybrid with a 3.0 gallon or 3.4 gallon oversized tank, filled to the brim, will feel less top heavy than a perimeter frame 1995+ KDX with stock 2.9 gallon frame or Clarke Mfg 3.4 gallon tank and taller KX or RM125 suspension front and rear.
That is the big motivating factor that would make me build a hybrid.
Otherwise I'll just be quite content with my upgrades on the shelf (swap soon!) to a 1"+ taller ride height '98 RM125 fork and '01-'04 RM125 shock internally lowered with KLX300 suspension dog bone links (will level out the ride height to match these forks), and adding a lot of titanium fasteners, linkage bolts, swingarm pivot bolt, and axles to reduce weight.
On less than 60 mile rides, I can just run my KDX's Clarke oversized tank with only 2.5 gallons in it in order to keep the weight lower (I run metering rod carbs - Lectron etc vs Keihin PWK, which extends fuel range 20%-25%).

Hoping to get some real world comparisons aside from just people saying that the slender 125 feels a lot more slender and agile. I'm not looking for desert racing stability or motocross handling, specifically looking for a bike that is even better at the gnarly tight woods technical terrain as well as 3rd or 4th gear fast flowing woods trails, AND is easier to pick up when dropped.

I can knock 12 or 15lbs off my bike with titanium fasteners, linkage bokts, acles & swingarm pivot bolts, titanium brake hardware kits and titanium caliper pistons, titanium cylinder head studs, titanium engine mount bolts etc. The 95-06 KDX frame really can't be THAT much weight difference than a KX 125... The engine and aftermarket pipe for a 220 weighs about 14lbs more than a KX125 engine and aftermarket pipe, which did have me heavily considering a 144cc build, but I love the lugability and rev-out of a modded 220 engine, it's truly like a downsized 300 with more top end.

I'm still leaning towards just keeping the two that I have and dropping a lot of money on titanium fasteners, as well as running a Clarke oversized tank not filled to capacity (I believe it does carry a little bit more fuel down low, not just added volume up top).

I'd appreciate some real world comparisons if you guys can chime in with your thoughts!
Last edited by Chuck78 on 09:31 pm Oct 15 2023, edited 3 times in total.
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

I was just drooling over the new TM 2-stroke EN 144 woods bikes as well as the Beta 200RR Race Edition model, but to be honest I can't justify spending that kind of money when the 220 engine does so well coupled with modified suspension.
The 220 is just such an awesome engine all around with a modified head and carb upgrade.
Last edited by Chuck78 on 09:32 pm Oct 15 2023, edited 1 time in total.
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

The KDX has a rake angle of 26.5° which is great for gnarly tight woods riding. The 96-98 KX125 is 26°, even steeper, which will turn even quicker. Some KX125/250 chassis from 99-08 have 26° up to 27.5° rake. The 27.5° rake would be the ones I would avoid.

Personally, the 96-98 chassis would be the most preferred overall, due to 26° rake, being a bit more compact vs later KX125 frames (I'm speculating here), & the big one - having purple plastics and '96 shroud graphics available for it... Although the purple '96 style shroud graphics are available for the 2003-2008 KX125, & a purple seat cover is no problem to get made up...

The 03-08 KX125 & KX250 share basically the same frame although the rake angle is a half degree different, & the engine mounting is different.
For me, keeping the bike compact and slender for weight savings and handling would be a big consideration, so a smaller frame size is definitely a consideration. The 250 models generally always show a longer wheelbase spec vs the 125, but still not as long as an '07 KTM 200 or a 2019 Beta 250RR, 2 bikes which are praised for their outstanding all-around handling.

Ultimately I'm just wondering if it is going to be a significantly noticeable "perceived weight difference" in handling for tight woods riding going to a 125/220 hybrid vs a modded 220 with taller '98 RM125 fork & reworked/7mm lowered '01 RM125 shock + aluminum KLX300R suspension linkage dogbones, and say just running the KDX fuel tank with the amount of gas that the stock KX125 2.25 gallons tank holds vs 2.9 or 3.4 gallons... The Lectron carbs really increase fuel efficiency drastically, and I never will hit reserve when riding with others anymore since shelving the venerable go-to PWK carbs.

Picking up the KDX after dropping in precarious situations on technical terrain or dragging it out of quicksand mud bog type scenarios biggest consideration here. The KDX H-series definitely feel very top-heavy compared to center spine type bikes like the E Series or most European Enduro models. That's the ONLY real complaint that I can't get over. I need to ride a nicely modded E-Series I suppose, as sticking a 220 engine into one of those with perhaps a DRZ400E shock and one of my spare '98 RM125 forks would perhaps fix the higher center of gravity issues, but then I have less pipe availability, but I could probably rework things to fit a 95-06 pipe into an 89-94 frame.... Makes me wonder how a KDX engine would fit into an '88-'89 KX125 frame as well!
Last edited by Chuck78 on 09:37 pm Oct 15 2023, edited 1 time in total.
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by bufftester »

I have a KDX220 Hybrid built on a 2001 KX125 frame with 2001 KX250 forks. I had my KDX from day one for 10 years and loved it. A wreck that tweaked the back half of the frame led me to do a hybrid build. The hybrid definitely "feels" lighter, though it weighs nearly the same. The rake on that year is .5 degrees steeper than the 220 frame which in theory should make it turn sharper, but the wheelbase is half an inch longer on the 125 so on the trail it feels a bit longer than the KDX and doesn't turn quite a s tight. Part of that may be because I haven't modified my steering stops which would give me a little more arc on the fork swing, but for what I ride it's not really an issue. The easiest way to describe it is that on the KDX I always felt like I was sitting "IN" the bike, and the 125 frame feels like you're sitting "ON" the bike. I prefer it as it really coaxes you to stand more (the seat on the hybrid is thin and HARD, sitting for any length of time gets a bit uncomfortable, but that would be expected from a MX frame). Honestly you could spend the money on the suspension of the KDX and get nearly the same performance, but for me at least the hybrid just feels better. Its an entirely subjective thing. My son has a 98 RMX250 which is a lot like what a race KDX would look like, and he prefers the ergonomics of it, but he is also 5 inches taller than me so the bike isn't really set up for him. The hybrid doesn't really feel top heavy, but then I never really felt like the KDX was either. In the flowy stuff the slightly longer KX frame really shines, in the super tight woods the KDX really shined for me. At the end of the day the only question that matters is given the choice would I go with a KDX again or with the Hybrid, and for me the answer is Hybrid
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

Seeing your second and third photos back to back definitely illustrates why the KDX might feel more top heavy than a KX125 hybrid... compare where the additional fuel weight is carried... ALL UP HIGHER!
The fact that a fair bit of the fuel tank sits under the KX125 seat, versus on the KDX with the fuel tank sloping up dramatically and having all of the additional volume up high... I think the fuel tank sits lower overall on the 125 as well, especially considering how one of the hybrid builds that I read of had issues with the KX 125 aftermarket desert tank's petcock hitting the KDX 220's cylinder head.
It is now even more apparent why the H series KDX has issues fitting a standard Lectron carb, Smart Carb, etc... That giant sofa of a seat! The shock crossmember sits much closer to the carburetor in order to make room for the very thick cushioned comfortable seat...

I still have a third 220 engine and only two bikes, and it is nice having a spare, but it may still continue to tempt me! I think a woods ported 144cc big bore with woods valving and 18" rim may be the better answer as far as shedding weight for a lighter feel and a bike that's easier to pick up. But a modded 220 engine is just absolutely brilliant in the gnarly nasty terrain... Since I started lusting after a 144 woods bike for the weight savings advantage, I really began noticing how often I lug the 220 and how well it lugs... I think I'd really miss that if running a 200 or 144.

Honestly I think a 220 H-series engine in an E-Series KDX200 with 1996+ Showa Twin Chamber forks and shock or even stock shock with RaceTech Gold Valves and identical looking Showa 49mm conventional forks but open chamber DRZ400 versions lowered 1" internally might perhaps make a much lighter feeling ultimate woods machine... This is a hybrid of sorts as well... The center spine E-Series frame allows the gas tank to carry a significant amount of the fuel weight much lower than an H-series, and those 88-89 KX derived side covers look too cool... Maybe I'll also keep an eye out for an E-Series roller with bad fork and no engine... And adapt H-series radiators and engine to it (the engine is basically a direct swap).
Last edited by Chuck78 on 09:44 pm Oct 15 2023, edited 1 time in total.
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

I definitely feel the difference of fuel tank positioning and size/capacity would make the KX chassis feel lighter, but I'll see what blowing some paychecks on Titanium fasteners on the KDX will do... LoL 😂
I was blown away with how heavy the swing arm pivot bolt and three big rocker arm linkage bolts weighed on my last suspension bearing replacement a few months back. So I tracked down KX500 titanium replacements for those, they are absolute feathers compared to the hefty stockers. I'll be running a titanium rear axle as well, although I have yet to find a good replacement for the 96-99 RM125/250 fork's axle (I've actually found that a '99-'03 KX125/250 axle is a bit more preferred along with a '99-'05 KX/KXF (& '04-'06 RMZ) wheel to retain the Kawasaki floating rotors.

Originally I intended to focus on titanium fasteners on the higher upper portions of the bike, as weight up high makes the bike feel heavier to pick up when dropped, but then I later realized that it was every bit as critical to shed 4-5lbs down low with just replacing these 5 substantially heavy chunks of steel!
Apparently the weight weenies even use aluminum bolts for the plastic bodywork...lighter and cheaper than titanium!
I'll be running titanium bolts for the handlebar clamps/risers and all 8 triple clamp bolts, as well as doing a VStrom DL1000 aluminum steering stem swap for my RM125 triples (same stem but too short, VStrom is just barely long enough vs short RM stem). The aluminum steering stem and Ti bolts up top will help. I have to resist the urge however to NOT spend $13 x 8 on purple titanium M8x45 triple clamp volts vs plain ti color for $4-$5 each x8...lol
Also got titanium brake kits with ti pistons, pins, banjo bolts, bleeder screws etc... Titan Classics even sells titanium KDX head studs & nuts!
Getting an order in for engine mount bolts in Ti as well shortly 👍
The fat 49mm conventional 98 RM125 Showa Twin Chamber forks will add some weight as well as rotor guards, skid plate, handlebar bag etc... So trying to shed as much as possible will be of great benefit.
Heck now I'm even considering using a stock purple tank instead of my Clarke oversized, and using a KDX SR model oil injection tank of the variety that mounts off the left rear subframe behind the side plate, as an auxiliary fuel tank for long hauls, as this sits lower by far... Although that location is a nice spot to fabricate a holster for a 10" blade folding saw or even a longer fixed handle folding saw and sheath :wink:
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by jakeslouw »

At the price of all the titanium, I'd rather just buy an Orange 300 TPi and get done with it. :twisted:
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

jakeslouw wrote: 03:22 am Aug 31 2023 At the price of all the titanium, I'd rather just buy an Orange 300 TPi and get done with it. :twisted:
With myself not really caring about electric start, and with Lectron Billetron Pro Series and SmartCarb SC2 36 carbs being as good or better fueling performance than KTM fuel injection, I'll be a good $5,000-$5,600 ahead financially to just modify my 220, which is one heck of a great platform to start out with... The cost of a new bike doesn't equate to the added benefits of buying a new bike...


Plus, they dont make KTM's in 1996 green/purple evo/revo era graphics, which is 1,000x better than being on a pumpkin colored clone of everyone else :shock:
White or solid red alternatives aren't much better, and I'd rather not buy a pumpkin only to drop another $450 on all black plastics and fuel tank :blink:
Last edited by Chuck78 on 09:50 pm Aug 31 2023, edited 1 time in total.
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

jakeslouw wrote: 03:22 am Aug 31 2023 At the price of all the titanium, I'd rather just buy an Orange 300 TPi and get done with it. :twisted:
I will say though that if they made a TBI version of the Husqvarna TE150i TPI model, that would be one heck of a great all-white bike as long as you don't mind carrying a spare fuel pump and other electrical parts to the trailhead with you 😂

Don't confuse me with an old geezer luddite who thinks all cars trucks and bikes should still be running points ignitions, but after having a wife who was formerly employed as the parts department manager at a European brands motorcycle dealership, fuel pumps fail on modern motorcycles a lot more frequently than you'd care to know, & AAA roadside assistance doesn't service the 5 Miles of Hell trail, Hatfield McCoy trails, etc...

:toimonster:
Last edited by Chuck78 on 09:52 pm Aug 31 2023, edited 2 times in total.
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

I'll also add that a Father/son riding team have a 2017 carb KTM 300 (Dad) with a Lectron Billetron Pro Series carb & a 2022 KTM 300 XC TBI, & the carb'd 2017 with the Lectron Billetron Pro Series reportedly has better top end power as well as every bitvas good of low end power and response... Similar reports from SmartCarb SC2 users on KTM 300's... Metering rod carbs are the absolute best once dialed in perfectly, if you take the time to dial them in or swap and tune different SmartCarb metering rods...
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by jakeslouw »

Chuck78 wrote: 07:02 am Aug 31 2023 I will say though that if they made a TBI version of the Husqvarna TE150i TPI model, that would be one heck of a great all-white bike as long as you don't mind carrying a spare fuel pump and other electrical parts to the trailhead with you 😂
I rode a TE150 TPI the other day: If I say I was gobsmacked it would be an understatement.

Dual map switch on the handlebars, go from mild to wild immediately. Light, torquey, yet will rev like a 125 on the fast map. Lovely suspension and a full size bike on top of it. Didn't even feel as if I needed to do much to accommodate my 105kg except play with the clickers.
Just a pity they are still attracting very high resale over here, otherwise I'd have sold my Chinese trail 250 and my pile of KDX bits a while ago and have parked one in the shed. Oh yes, and my wife loves them. :mrgreen:

To go back to suspension: I'd say a KDX200/220 with a SS109s CDI, an FMF Gnarly, in a tweaked 99-02 KX125 frame with revalved suspension would be the dogs bollocks. That sort of where I'm going.
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

jakeslouw wrote: 01:03 am Sep 01 2023 I rode a TE150 TPI the other day: If I say I was gobsmacked it would be an understatement.

To go back to suspension: I'd say a KDX200/220 with a SS109s CDI, an FMF Gnarly, in a tweaked 99-02 KX125 frame with revalved suspension would be the dogs bollocks. That sort of where I'm going.
Yes, the modern 150's are absolutely AWESOME... FYI looking at the specs, the Husqvarna versions are slightly less extremely tall than the KTM versions, by a half inch iirc? I would be very reluctant to ride a KTM brand bike, and especially an orange KTM, but the 150 would be the biggest sway to do so... 300's are popular for their ease of rideability and monstrous and broad torque - you barely have to shift gears on singletrack as the engine pulls well across the whole power range. But not everyone actually needs that much power, and the slight added weight of the larger engine and chassis, not to mention the handling losses from a bigger crank/piston/rod + balance shaft - as the gyroscopic effect of that added mass makes the bikes have a greater tendency to resist change of direction, meaning the heavier the rotating mass inside the engine is, the more the bike wants to stay upright at times when you want to whip it over to the side in a turn etc... They feel less nimble. Also a fair bit heavier to pick up when dropped.

If I were to actually look at selling my venerable and ultra reliable old KDX or at least buying a new bike (not for $10K unless I win some sort of lottery!), I'd really have a hard look at a Beta 200RR Race Edition first and foremost, and I'd probably switch immediately to a SmartCarb SC2 36 for the added low throttle low rpm response and torque that the SmartCarbs give which even fuel injection cannot match (Smart Carb have patented the venturi shape that give this amazing response). Loving my KDX220 tremendously, I'd originally thought that a Beta 250RR Race Edition would be the bike to have, but the 200RR is lighter and the SmartCarb addition would boost the low end power more. That'd be a difficult machine to beat. Beta did have some issues with engine bearings wearing out prematurely in the late 2010's as well as wiring harness connector issues, but they've addressed those issues, and I really like the feel of their bikes and the chassis design/layout better than any other dirt bikes. Have to add all black plastics though as the blue and red doesn't do it for me... easy fix for cheap though!
The added weight of e-start on a bike is not really worth if for me though, but since the weight is down low, perhaps it won't make the bike feel any heavier on the trail to pick up? The fuel tank droops well down on the sides, so the center of gravity is far lower than an H-Series KDX, which really helps with a lighter feel, as would running a KX125 or Beta fuel capacity in the larger KDX gas tanks instead of topping off!

One last modern bike rant - TM's EN 144 2-stroke enduro bike is another absolutely brilliant one... Wow. TM are all hand built and absolutely incredibly designed very well thought out machines, and perhaps the best aluminum frames on the market... That'd be another very tempting model, IF I suddenly happened upon a large sum of money :lol:
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

This was a really interesting thought... The KDX seat is quite the sofa versus an uncomfortable modern bike seat or a KX125... and my neighbor buddy did comment to me that the KDX H-series seats are the absolute most comfortable bike seats he's ever sat on, even 20-30 year old original foam!
In other words, THAT'S A LOT OF FOAM! But foam is light, is it not? See this post that I dug up on ThumperTalk when reading about shear strength and anti-sieze with titanium fasteners and axles on bikes:


Drop-Bear on Thumper Talk forum, Oct 18, 2020 wrote: There was a bloke on here yrs ago from Italy. He built a really light weight CR125AF. He said the 2 biggest weight savers were the titanium shock spring and the Guts Phantom or Think LW seat foam.

The Guts Racing Phantom seat foams are a lot lighter than OEM, It's a huge weight saver, and the weight is higher up.
Very interesting... I wonder if they still make foam for our KDX seats?



From the manufacturer:

"Ultra-lightweight seat foam is not new to many factory top level pro riders. Many factory race teams have discovered that removing small amounts of weight at the highest point on a motorcycle has a great impact on the way that machine handles. The Phantom Ultra-Lite seat foam has shown outstanding durability and the closed cell design keeps it from soaking up water.

*While other companies have tried to make this foam available at a much higher price, GUTS Racing can now offer it as an affordable option.
*Used by more factory race teams world wide than any other brand.
*The Phantom foam has a slightly firmer feel than the stock foam."





I just emailed Guts asking about this. They do list our models in their product finder, along with several customization options. I'll just copy & paste:

"How can I get the Phantom Ultralite seat foam for my KDX seat? I see you have various options for 1995-2006 Kawasaki KDX seats, but the Phantom UltraLite is not displayed. Since you do so many different custom bump/rib/height options, I can only assume that these are all made to order?"
Last edited by Chuck78 on 09:14 am Sep 02 2023, edited 1 time in total.
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
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'77 Suzuki GS750-844cc, '77 GS400/489cc & '77 GS550/740cc projects
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by KDXGarage »

Chuck78, the stock foam is really heavy compared to the super high dollar foam. The super lightweight foam probably is not for an all day ride.
Thank you for participating on kdxrider.net. :bravo:
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

In other weight reduction efforts, I've discovered Mettec has a really good variety of 6AL-4V Titanium bolts listed in their Marine section for cheap, but the parts in their bike-specific fitment sections are extremely pricey, and I thought Race Tech Titanium's prices on axles etc were a fortune!!!

I found them searching M10-1.25 x 105mm lower engine mount bolts. Best bang for the buck is to replace all the largest heaviest steel fasteners with titanium first, and all the fasteners higher up on the bike where the weight is felt the most - the handlebar mounts and perches/risers, triple clamp bolts, fork swap that retains al aluminum steering stem if possible, Guts Phantom Ultralite seat foam, etc...
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

Looking at some of these hybrids and seeing the aluminum rear seat subframe on the 2003-2008 KX125's really made me think again about my spare 220 engine's fate as a spare on the shelves, or potentially getting to be part of a KX220 hybrid in a 125 chassis...

Then I found that you can buy aftermarket aluminum seat frames for pretty much every viable hybrid KX125/KDX chassis donor by seeing used aluminum KX125 seat subframes for 1989, 1995-1998, & 1999-2002... 2003-2005 (-'08 internationally) came stock with an aluminum seat subframe.

Looking at the geometries, the 95-98 ('96 spec at least) have a 26° steering head rake (caster), steeper than the KDX's 26.5°, so that's a big bonus for tight woods handling, as well as the '96 having a shorter wheelbase at 1,455mm.

'95-'98 can run the purple '96 plastics, HUGE BONUS, but the aftermarket tank options require their own custom shrouds, or modifying the stock shrouds... So you might be stuck running the tiny stock tank,but at least that'll keep the weight down and center of gravity low. Run a Lectron Billetron Pro Series carb or SmartCarb SC2 36 for 20%+ better fuel economy and fuel tank range and you won't be affected as much by the small stock motocrosser tank size

'99-'02 have a large amount of aftermarket tank size options including up to 3.4 gallons, 4 different IMS tanks and 1 or 2 Clarke Mfg tanks. That's a lot of options... Good aftermarket support for this era without a doubt.

'03-'05 ('08 internationally) have a stock aluminum rear seat subframe and the gas tank, even the IMS or Clarke oversized, sit lower in the frame for a better lower center of gravity. This is the big reason for a hybrid - a lighter feel due to lower center of gravity. 27° steering rake angle on these, but dropping the triples down on the fork tubes can get it to stock KDX220's 26.5° rake/caster angle to get that tight woods steering angle back

I'm going to start compiling specs year by year here to compare. I'm leaning towards either keeping my eyes peeled for a purple '96 with it's shortest wheelbase and steep 26° rake, or an '04-'05 (you can get purple '96 style graphics for the '03-'08!) with it's lower tank but longer wheelbase unfortunately.
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

Adding more geometry and revisions info as time allows below:
(Specs direct from Kawasaki brochures found here: https://flic.kr/s/aHsk7LiU2S )

H-series KDX chassis:
26.5° rake / 4.3" trail
56.5" wheelbase
36.2" seat height
2.9 gallon tank
223lbs claimed dry weight


1995 KX125:
26° rake / 4.3" trail
? wheelbase
37.4" seat height
2.25 gallon tank
191lbs claimed dry weight

1996 KX125:
26° rake / 4.3" trail
1,455mm (57.3") wheelbase (KX250 = 1,460mm)
37.4" seat height
2.25 gallon tank
190.6lbs claimed dry weight

1997 KX125:
26° rake / 4.3" trail
57.3" wheelbase
37.4" seat height
2.25 gallon fuel tank
191lbs claimed dry weight

1998 KX125:

1999 KX125:
26° rake / 4.3" trail
56.5" wheelbase
37.2" seat height
2.25 gallon fuel tank
192lbs claimed dry weight

2000 KX125:
26° rake / 4.3" trail
56.3" wheelbase
37.2" seat height
2.25 gallon fuel tank
192lbs claimed dry weight

2003 KX125:
27.5° rake / 3.9" trail
57.3" wheelbase
36.6" seat height
2.17 gallon fuel tank
192lbs claimed dry weight

2004 KX125:
27° rake / 4.4" trail
57.9" wheelbase
37.2" seat height
2.2 gallon fuel tank
192lbs claimed dry weight




(Work in progress, I've got some brochures pulled up in my browser to compare specs and add more here)

http://www.kxriders.com/forums/index.php?topic=17180.0
2003-4 KX125 Rake/Trail: 27.5° / 3.9 in.
2005 KX125 Rake/Trail: 27.5°/ 4.3 in

2002 KX250 Rake/Trail: 26° / 4.3 in.
2004 KX250 Rake/Trail: 27° / 3.8 in.
2005-7 KX250 Rake/Trail: 26° / 4.1 in.

'96+ upgraded from 43mm forks to 46mm forks
'97-'98 thicker cross section swingarm
'97-'98 additional bearing & improved sealing in rear hub

2003+ steering stem is 6 mm taller.

'03-'08 changes:
'03 = new hydroformed aluminum swingarm that's 100 grams lighter, '04 swingarm was extended 17mm longer
'03 have the conventional shock linkage design, '04+ changed to the simplified 2-piece design (Pro Circuit linkage is highly recommended for better handling as well as the underlying issue, the need for re-valving the '04+), rear linkage rocker arm design is now connected to the swingarm and not the frame.
'04-'08 engines are completely different than '03, as is airbox angle to carb and intake angle.
'05 got a taller seat foam.
'04 switched to CR style fork gaurds and brake routing (which makes huge difference in the front brake)
'04 foot pegs where raised 5mm over the '03 to eliminate feet contacting ruts/roots/rocks under deep suspension compression.
'04+ revised triple clamp design in
'04 got the 48mm KYB bladder forks, '03 had the older rubber bumper style.



*I believe the '03-'08 125 and 250 frames are identical (but '04-'08 linkage mounting & exhaust mounting changed), but I suspect the 250 has a longer swing arm (will compare wheelbase when I compile more specs).


*'03-'08 KX had the slimmer & improved chassis, the frames were a lot smaller and more compact than the '99-02 generation KX's, & will feel cramped for taller riders

*'04-'08 - check where the suspension linkage mounts to the frame, crawl under it & look at the mount from the linkage to the frame, very close to the swingarm pivot. Make sure the bike has not been ridden with this joint loose. If it has, the hole ovalizes, & it will be impossible to ever get the linkage to stay tight again without welding & machining to repair.

*250 riders did not like the '05+ steepened rake of 26° vs 27° prior, & felt the MX handling to be better at 26.5° vs 26°
Last edited by Chuck78 on 01:15 pm Oct 09 2023, edited 15 times in total.
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
'77 Suzuki PE250 & '83 Suzuki PE175 Full Floater - restomod projects
'77 Suzuki GS750-844cc, '77 GS400/489cc & '77 GS550/740cc projects
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'88 Suzuki Samurai TDI/Toyota swaps
'88 Toyota 4x4 pickup
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by KDXGarage »

Wet weight on a 2005 KX125 is 208, as measured by Dirt Bike magazine. That meant no fuel at all in the fuel system, I think.
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by Chuck78 »

KDXGarage wrote: 01:04 am Oct 09 2023 Wet weight on a 2005 KX125 is 208, as measured by Dirt Bike magazine. That meant no fuel at all in the fuel system, I think.

I thought wet weight was WITH fuel? I was talking about the new YZ125X woods bike version of the YZ125 motocrosser yesterday with my brother, and I saw a few places listing the wet weight at 209lbs, but motocross action's review stated it "tipped our scales at 212lbs with fuel topped off."
2.25 gallons of fuel weighs more that 4lbs so I thought that was just a slight discrepancy and both would be considered "wet weight?"

Gasoline weighs between 6.1lbs to 6.3lbs per gallon depending on octane rating and additives / content.

I know the KDX is published as being 223lbs, but that has to be a dry weight. I've read a hybrid builder here stating with all protective gear - skid plate, bark busters, pipe guard, rotor guards, upgraded DC electrical system, aftermarket pipe and spark arrestor (8-12lbs weight savings), small tool bag, and fuel, their KDX weighed 238lbs I want to say???? And iirc the hybrid weighed slightly less (228 or 232 or vicinity).
The KTM 200 is listed at 221lbs (wet?) but I read the dry weight is 208lbs. They definitely have a lighter feel than an H-Series KDX (but I still prefer a KDX220 over any KTM 200). Of course that's with more alloy parts such as shifter and brake pedal, every single bolt head dished out to shave weight off, aluminum seat subframe, etc
a lot of titanium parts onto a KDX or a KX125/220 hybrid could certainly get the weight down to nearer the KTM level, and we'd have our incredible 220 engine still...
'97 KDX220R - purple/green! - KLX forks, Lectron, FMF, Tubliss
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron Pro, Tubliss
'77 Suzuki PE250 & '83 Suzuki PE175 Full Floater - restomod projects
'77 Suzuki GS750-844cc, '77 GS400/489cc & '77 GS550/740cc projects
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Re: KX125/220 hybrid vs upgraded suspension on 95-06 KDX

Post by SS109 »

I know it's a bit more work but don't forget about the '04-'05 Kawazuki KX250F/RM250F chassis'. They handle great, are steel framed, and because of them being steel, can be modified to fit a 2T engine a lot easier than the '06 and up aluminum frames. These bikes were great other than the Suzuki designed engine they came with.

On weights, my '98 KDX220, with Warp 9 rims, EE wrap around handguards, Scotts steering damper and aluminum skid plate, '06 KX250F forks and RM125 shock, with 1 gallon of fuel in stock tank, tipped the scales at 242lbs. I'm hoping to use my '06 KX250F chassis to build me a hybrid, now that my Gasser has been completed, and hopefully shed about 20lbs of weight. Should make for a nice enduro weapon!

Wet weights are normally considered all fluids needed to run but with no fuel. Over the years when they do include the fuel weight they'll normally state as such.
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