Does anybody have any hard figures on the benefits or drawbacks of oversizing the KLX 250 jug?

Which kit offers the most bang for the buck?

The 350 kit is new and, while I'm sure BB knows what he is doing, seems it might be stretching the limitations of the original package a tad.

What's the scoop on the 331 and 340 kits? Where is the 340 available? Do they cost about the same?

I've got some Keihin 35mm FCR carbs coming and one of them is going on my KLX. The next big step after that is THE BIG bore!!

I know a few guys that are into dual sport riding. They ride a DRZ 400, DRZ 650 and an XR 650. They like the power on the black but not the weight woods. The trails here are pretty tight and light is good. One of them knows I've got this little KLX and took it for a spin before I did mod #1. "handles nice" was all he said.

None of the mods I'm doing will be obvious at first glance and I'd really like them to drop jaw and cream themselves when we take the lowly and light KLX for a romp with it's bigger badder cousins .

After the FCR and some suspension tweaks the big bore is topper. I'm trying to edumakate myself on the big bore options.

Any specs, recomendations, thoughts, availability options, pros n cons or just plain ol informed opinions are all greatly appreciated.

 

I'm curious about the 300 myself...

 

The search for maximum performance is by definition taking it to the limit. I've ridden the 351 and the 300. Both are great choices. I think Bill Blue will be glad to discuss the different sizes with you if you contact him directly.

 

As long as the 351 piston is close in weight to the 250 or 300, it would not be stretching the limit that much at all. The bottom end of this engine is pretty strong, and should handle these upgrades just fine.

 

I know this is noob-ish, but can someone explain the whole idea of the "300" to me? Isn't it just changing out a piece of the motor? As in, NOT boring out the cylinder? Its just a different bottom end, correct? Link to some information? Or an explanation? I'm just kinda curious. I don't wanna bore out my motor, but I'm interested in a bit more power but still reliable (in addition to exhaust and carby, which I'ma do first... I'm just trying to learn).

 

yup, I agree.

 

You exchange the cylinder, not the bottom end. While you yourself would not be boring anything you would have to purchase a new cylinder with a larger bore and replace your stock 250 one.
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Fetish Vids

 

My understanding is Bill specifically designed the 351 piston to weigh the same as the 300.

 

After putting ina 350 kit, pipe, jet kit/carb, air filter, etc etc..... first thing I would be worried about is the clutch.... not the bottom end or piston weight.
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Uggs

 

So basically I'd be buying a new piston and cylinder, and installing it underneath my stock top end and inside the 250 case and outter guts?