The best 2006 Honda twin-pipe CRF250 (above) is a 2005 Honda CRF250 single-piper.


Dear MXA,

I got a low-hour 2006 Honda CRF250 as a hand-me-down from my uncle for free. It runs and is in good shape; however, I’d like to make it even better. Can you give me some tips?

The 2006 Honda CRF250 was essentially the 2005 CRF250 with twin pipes and a bigger carb. It was a competitive bike in its day and would be a very good starter bike 14 years later, but only because you say it has low hours. Here is MXA’s quick list of the mods and changes we made back in 2006.

Rear sprocket: The CRF250 gearbox has too large of a gap between second and third gear. The stock gearing lays down if you try to short-shift. Second is a little too low and third is too high. There are two possible solutions: (1) If you are fast, stick with the stock gearing and carry as much speed as possible. (2) If you are slow, gear it down with a 52-tooth sprocket (this will make it easier to get to third).

Stiffer clutch springs: The stock 2006 CRF250 clutch unit lacked strength. The quick fix? Stiffer clutch springs. You’ll think somebody hopped up your bike when you feel the extra bite of stiffer clutch springs.

Fork springs: As was common in the mid-2000s, Honda delivered the CRF250 under-sprung. Get 0.48 kg/mm fork springs, drop the oil height 10mm and enjoy the improvement.

Smaller carb: For 2006, Honda mounted a 40mm carb on the CRF250. Most MXA test riders preferred 2005’s 37mm Keihin FCR because it didn’t bog when you landed from jumps. If you have access to last year’s carb, mount it on your 2006 and you will be amazed by the improved throttle response.

Jetting: If you stick with the stock 40mm carb, you should try changing out the 172 main for a 170, 40 pilot for a 42, 70 leak jet for a 45, NHFS needle for an NHFT and removing the float-bowl baffle.

Boyesen Quickshot: Part of the CRF’s bogging problems can be resolved with a Boyesen QuickShot accelerator pump cover. It’s not a 100-percent fix (for that you need a 37mm carb), but it will help.

Oil—and lots of it: The CRF250 needs all the oil it can get. Check the oil level before every ride and never let it get low. It only carries 650cc of engine oil, and if it gets low, it will get lower in a big hurry.

Radiator braces: Honda’s radiators are prone to bending, and not only by crashing, but also if you hit them with your knees. To keep them from getting U-shaped, mount a set of Works Connection radiator braces.

Single-sided pipes: Honda requires its sponsored race teams to use twin pipes as part of their contracts. The MXA wrecking crew has tested all manner of 2006 CRF250 pipes, and we have had our best luck with the less-expensive, lighter and simpler single-sided pipe. You might have trouble finding a 2006 single-sided pipe in stock, but try DR.D, FMF and Pro Circuit, because they all made them back in 2006.

Ultimate CRF250 fix: The MXA test crew took the pipe, subframe, airbox and carb off our 2005 CRF250 and put it on the 2006 model. It turned it into a better bike with a snappier response, a harder pull in the middle and better jetting. In reality, that means that you need another generous uncle—only this time with a low-hour 2005 CRF250 instead of a 2006.


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