Question about 1993 Honda NSR 250 MC 21

1 Answer

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

Posted by on

  • 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



1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Brigadier General:

    An expert that has over 10,000 points.

  • Master
  • 6,966 Answers

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


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

How do i fix a rough idle

High is normal, as the cold engine has thicker oil and does not vaporize fuel well, so needs to run faster until it warms up.
But the rough chugging sound could either be weak spark from arcing wires or coil packs, or could be a lean mixture. Lean mixtures could be from a stuck EGR or purge valve, that you can test by temporarily plugging them off. Or from a leaking hose that fell off, that you can try to pinpoint by listening for the hissing. Or low fuel pressure that you can test for with a fuel pressure gauge. A dirty fuel filter could cause that.

Feb 10, 2016 | Cars & Trucks

2 Answers

Hi there, I have a Honda nsr MC21. I have been told that my crankshaft bearings/seal has gone. The bike wont start, if I spray/leak a little fuel directly into the carbs, it starts like a dream. I was told...

Difficult starting is a classic example of a faulty centre seal.The seals tend to harden up and leak after time and particularly with certain fuels.

Oct 22, 2013 | 1991 Honda NSR 250 MC 21

1 Answer

1993 Honda NSR 250 MC 21 how to replace the clutch

Hi, Jachoneethli for this scenario you will need your service manual, parts fiche, and owners manual if you can't find the best tool you ever bought for your Honda, despair not, for a mere zero $0 you can download another one.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
NSR250 Other Questions
Honda nsr250 mc21 dry clutch video
Honda NSR250R SERIES Service Manual
Honda NSR250R

Btw, I’m available to help over the phone in case u need at

Feb 27, 2012 | 1993 Honda NSR 250 MC 21

1 Answer

91 cr125 piston will it fit nsr250 mc21 honda

impossible buddy a 125 is a smaller piston than a 250 just buy a nsr 250 piston

Aug 09, 2009 | 1992 Honda NSR 250 MC 21

2 Answers

NSR250 MC21 92 Not hitting power band, fine until around 7000rpm

not familiar with your bike but some bikes have electric controlled power band an some have mechanical.Electric ones usually do a quick self diagnostic on start up hope that helps

May 22, 2009 | 1992 Honda NSR 250 MC 21

2 Answers

Whats under the engine case, what goes in each container?

2 stroke oil feels alot different than brake fluid and is usually blue or green ,where brake fluid is supposed to be clear but might be root beer brown in a 1991 bike. Stick your finger in and you'll find the one for oil....Good luck to you friend....Tim

Apr 25, 2009 | 2001 Honda NSR 125 R

1 Answer

Nsr 250 mc21 low on power

you don't give much information on how the bike is running.  But most times when there is a performance decease it is best to clean the fuel system.  Spray some Gum Out or similar product( I prefer Deep Creep and Sea Foam) in the carb. then follow up with some in the tank.  Also change the fuel filter.

Jan 04, 2009 | 1993 Honda NSR 250 MC 21

1 Answer

Nsr 250 mc21 bike battles to kickstart

i bought a peugeot 306 gti6 the radio dont work it got 8 dots will i have to have it decoded

Jan 04, 2009 | 1993 Honda NSR 250 MC 21

Not finding what you are looking for?
1993 Honda NSR 250 MC 21 Logo

207 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honda Experts

Arnie Burke
Arnie Burke

Level 3 Expert

5065 Answers


Level 3 Expert

81423 Answers


Level 2 Expert

342 Answers

Are you a Honda Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides