I'm curious what is a reasonable top end for these bikes all the mods, 351, exhaust, cam, other mods and maybe mild porting.

I think I've decided the KLX250 (KLX351) beats the WR250R (WR290R athena) at my skill level (KLX cheaper, more torque, WR slightly better suspension which I wouldn't be able to take advantage of)

So to fill my needs of a light weight dual sport I am debating

KLX 351 putting all efforts into lightweight and engine mods

vs

DR 350 putting all efforts into updating suspension (fork swap, new rear shock), lightweight, and engine mods... It should be noted that the DR can be bored to 440cc...

I think the KLX being newer would look tidier with less work.

It should be noted it would be replacing a KLR and I'm not interested in the DRZ, XR, or any other bike thats not right around 300lbs or durable

Thanks

 

Drz400e plated with 440 athena kit. 292 wet, 48 horsepower.

 

I'm going to 2nd the DRZ, I've had mine for 5 years of pretty hard off-road and it's a champ. ....EXCEPT in the tighter stuff. It only weighs about 15# more than the KLX (but admittedly does feel like more) and the power is night and day.

 

I have a Thumper Racing 340 cylinder on my KLX250sf.

Now if I had to do it again I would of started with a bike with more displacement from the start like the DRZ400 or the KLX400

Depending on you abilty to do the work your self it will cost you more to upgrade the KLX or the WR than to start with a DRZ400 if you are looking for max HP on a Dyno

Upgrading the KLX could cost you just short of $2000 and the most power I have seen claimed out of the KLX with a big bore kit is in he low 30HP range and this included new cams, larger valves and other head work which could add another $500 or more to the project. So not including labor around $2500 plus to upgrade the motor and suspension and in the end have low 30HP. I can buy a slightly used KLX400 or DRZ400 for $2500 to $3000 and have the same power.

The other question relates to how much punishment you can dish out to the big bore motor that was designed as a 250.

Big Bore Kit 351 $535
New Carb $385
Full FMF $ 400 to $500
Suspension: The stock KLX spring rate was soft for my weight 195lbs and I had to replace the springs front and rear another $250
I added RaceTech valves in the forks another $140.

The above does not include motor oil, fork oil, fork seals and bushings if needed, shipping cost and labor if you do not know how to do all or some of the above.

Now to the DR350: If you want a great third-world bike this could be the puppy to own. It is air/oil cooled so less to worry about if you crash it hard but usually air cooled motors do not allow for as much HP out of the box as a water cooled bike. Yes you can punch it out to a 400 or 440 for some big bucks if anyone is still offering a big bore kit. Just like the KLX the cost to upgrade is going to bite you in the wallet.

If you want more power find a used KLX400 or a DRZ400 and start from there. There is a bigger aftermarket for parts for these bikes and they have a stronger motor in stock than the upgraded KLX, WR or DR350 could ever hope to be.


Do not get me wrong: I love my little KLX340 and I have had fun doing all of the work but If I knew what I know now I would of started with a different bike and would of spent just as much money being that I have to tinker.

 

I agree with tkm433. However, my dyno testing indicates that 22(+)hp is easily achieved for about $210.00.... That's a new DG-R ($150) and DynoJet kit ($60)..... See my signature line for my other mods and dyno test posts....

This makes the bike quite enjoyable. The insurance on the KLX is DIRT CHEAP ! While I don't know how much more the costs would be for a bigger bike, the cost of ownership of the KLX is DIRT CHEAP !



BTW, add a BB351 to my bike and you would expect 25-26 hp. This would be a total cost of about $750.

 

If you want more HP, why not just get a 450mx bike and put a light kit on it? Take your choice from Kawa,Suzuki,Yama, or go Orange. Even a Huski would fit in there.

 

a fully modded KLX (big bore, cams, exhaust, pumper) should be able to put down 33-35 HP. That's pretty respectable for what it is.

That being said, it would likely be easier to plate a 450 MX bike and blow the KLX out of the water if you can swing the extra cost and jump through the hoops (assuming its legal in your state).

 

Thank you for the replies! For an idea of my riding I put over 15,000 miles on my KLR last year. City commute with hooliganism, cross country cruising, crashing a lot in Utah and the Colorado mountains, general use and abuse.

To make the DRZ cruise cross country it would need an ACR Wide Range transmission in there because of the gearing issues. Coming from the KLR I gotta ask: what makes it feel top heavy? I love how people say the KLX feels like a motorized bicycle.

There isn't another 450 bike that is reliable, all of them have small oil capacities and maintenance intervals and most have close ratio transmissions for faster acceleration in races

I've heard good results from some KTM 530 owners but I have also heard of people ruining cranks at 5,000 miles.

I think with the huge success of the WR250R the companies will have to get it together in the next few years and make a KLX450S or a WR450R

The DR350 has 6 gears to start, can be found for super cheap. I feel like I'd be replacing everything on most bikes anyway (air filter, bars, switches, chain, tires, seat, lights, probably a big bore)

I would do all the work myself.

DR350 $1200
USD Front End $1000
Bigbore 450 $500
Farkles $500

$3200 for 300lb bike, with modern suspension, six gears, 450cc air cooled, Japanese reliability and I'm sure insurance on a DR is cheap as hell.

 

Isn't a reliable 450?

Wr450
Klx450
Husky 610

 

Thinking about taking this all on... What is the DG-R? Is that the airbox? Did you change the exhaust (pricey $)