2005 Honda CBR running poorly

rosmoe

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Nov 2, 2004
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Have a 2005 Honda 150 CBR, runs good in the flat lands, but up in the mountains around CM runs poorly, like it is starving for gas. Can anything be adjusted in the carburator to make it run better up on the higher roads? Any recomended mechanics to fix the problem ???
 
Jun 28, 2010
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It sounds like it may be running rich and in need of re jetting.
I was talking to Nan at the Piston shop about this same problem a few days ago.
The air gets a bit thin at altitude and less O2,so a bike can start to run a little rich and lose power up in the higher hills.
Might pay to drop in and see Nan and see what he thinks,not sure if its a common problem with 4 stroke engines up around here.
 

rosmoe

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Nov 2, 2004
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Thought that might be the problem. Took it to the dealer, they just changed the airfilter. A lot is lost in translation around here. Thanks for the fast reply. Will see if the Piston Shop can correct the problem. A lot cheaper than buying a new Fuel Injected CBR 150, although they are a great looking bike !!!
 

mikerust

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Subscribed
Nov 5, 2003
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bhp loss = elevation in feet / 1000 x 0.03 x bhp at sea level

From here https://docs.google.com/viewer?url=http://www.sharkpw.com/Upload/CategoryDocuments/c997b38a-48f2-4d41-bb12-f365b99f2397.pdf&embedded=true

So according to my calculations in Chiang Mai city you are losing 0.36hp. In Chiang Rai 0.70 hp.

Is the bike originally from Chiang Mai? Maybe bikes are set up differently in the North?

If you have any mechanical aptitude you can adjust for the bottom end of the range by adjusting the air screw. This will reduce the fuel slightly if and only if the bike is showing signs of being too rich. But it may not solve any full throttle drive ability problems. In which case you'll have to fit a smaller main jet.

But you can't get back the loss from altitude without other mods to boost overall HP.