with a 51, you would be at almost 8500. If you don't ride on the road for more than a couple of miles, not too bad. ... for 20, no way for me.

 

Early on in the first couple of months probably around Feb of 2006, I went from 14-42 to 13-45 at that combination, I'm at 7000 doing 60 according to the Garmin. I've ridden that speed and RPM for really not more than 30 miles at a time on the highway. I don't think I would want to do that much longer.

 

Thanks everyone.
Think I will go for 14:48. I've read somewhere else on the forum that it's do-able without altering any furniture.
Will report how it goes. Won't be for a while as have broken fibula.
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My experience on my '09 KLX250S which is my 95% dirt/trail bike. I try and stay off the pavement. We don't have many hills, but plenty of sugar sand.

Stock sucks..
13/42 is better, cheap and easy, but still too much for slow technical and/or sugar on a stock motor. Probably a pretty good combo for mostly street riding.
14/49 was great on technical singletrack, but very busy up above 55-60 mph between trails. Works well in the sugar even with jetted 250cc. (requires a longer chain - 110 links)
14/47 is my current setup after jumping to 331cc and it's a keeper for me. Keeps the revs up in the fun-zone, still decent for slow technical, busy but not too busy on the slab between trails. No problem staying up on top of the sugar. (requires a longer chain - 110 links)

If I spent more time on the road, I think 13/42 or 14/45 would work really well on more of a 50/50 331cc

I think 14/48 is a good dirt biased all around setup.

 

I run a 14/48 with a 110 link chain, all stock guards still fit. I can easily top 70 mph but don't like going more than 50 ish, always checking to see if I'm already in sixth gear (or searching for a seventh haha). This set up isn't bad and with the same chain I can put on a 13 tooth front sprocket for single track and if I put a 15 tooth on (still same chain) I am fairly close to stock gearing. 48/13 = 3.69, 48/14 = 3.43, 48/15 = 3.2, 42/13 = 3.23, 42/14 = 3 (stock).

 

Thanks. Is it a 250 or big bore?
If 250, what mods and ejk settings (if fitted)?

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Ran it as a 250 but have since added the Chinese AHL Tong Tong 299 cylinder (actually 292cc). Carbureted, but using a Mikuni TM 36-68 pumper carb, uses a cable controlled metal slide for throttle instead of relying on vacuum like the stock CVK constant velocity something or other carb...

 

reinigef,

I like your idea a LOT. That 48 on the back and having a 13, 14, 15 on the shelf in the garage results in a wide range of final gearing combinations, depending on riding conditions. I think I shall follow your advice. Thanks!

 

I did the same, 48 on the back and 14 or 15 front. But most of the time riding 15/48, found it is good enough both for road and offroad with 351 engine.

 

I run a 14/45 combo on my 351. Plenty of grunt for technical stuff and doesn't feel too frenzied at highway speeds.