Question about 1993 Honda NSR 250 MC 21

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NSR mc21 Yeah it runs now and no leaning problem but now i have a fuel issue at about 7000rpm in whatever gear it chugs for fuel or somthing and looses revs, im thinking it might be to much pre-mix in the tank with the now working oil pump witch i had replaced earlyer that day im gonna take it for a ride today and see if i can clean it out of the tank with some good premium petrol thanks again you have been a great help its my first 2stroke lol

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  • numbang Dec 01, 2008

    good job thank you an i will look at the carbs now and sorry yeah i didint know how to help you stats i hope that i have fixed that now


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Hi again,

Am glad that your bike runs now albeit the 7K flatspot. I have to agree that if you have a pre-mix in the tank and the 2T oil pump is already working, the fuel mixture tends to be harder to burn and would produce a smoky exhaust. Even having said this, I beg to disagree that this would be the cause of the hesitation/flatspot on about 7K RPM. I suspect that you have an air leak somewhere, most probably before the carbs. This would be the airbox assembly, the collar/mating/coupling to the entrance of the carb or even the air filter itself (or more so in the absence of an air filter). You may want to check that no air can enter the carbs other than those that passes through the filter.

On a side note, this would be the third post that you have made on the same bike and I have answered them resulting in what is now a rideable bike. Perhaps unknown to you and due to my current standing at the site, even a "Helpful" rating would be detrimental and would be bringing my stats down. Normally, this should discourage any further attempt to provide assistance, however, as earlier premised, "perhaps unknown to you"...

Good luck and Thank you again for using FixYa.

Posted on Dec 01, 2008

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