Good morning. I am putting the finishing touches on a basket case NSR 250 (and I appologize, this is my first one). On the bottom of the tank, almost directly below (or opposite) the filler opening, there are 2 hose connections. One small (.25" or 5mm +/-) and the other a bit larger (.35" or 9mm +/-). It appears the small one goes to the "air jet SORENOIDOValve ASSY".

My questions are, is this correct and where does the larger one go?
Thank you in advance for your help.
Mark
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The fuel tank is connected via the fuel tap as shown in this diagram:
http://workshop.nsr-world.com/11kv3lj7/2FK11KV3LJ7/H13Frame.html

The fuel tank overflow drops into a little plastic thing in front of the airbox (is a part of it) and drains out via the tube (part 19):
http://workshop.nsr-world.com/11kv3lj7/2FK11KV3LJ7/I8Frame.html

Part #9 in the above plugs into a little hole surrounded by rubber in the bottom corner of the airbox.

I think these are what you are talking about?

Show us some pictures.
Only one hose (the fuel hose 3/8 i.d) connects to the fuel tank.

I'm not exactly sure how to post pictures but I will try. I should have mentioned that this bike does not have an airbox, It has K&N individual filters. Compounding the problem, I can't find the key to open the fuel tank and look inside to see the hose nipples from inside the tank.

The 3/8" fuel line connects to the fuel valve assembly, yes?
I will work on the pictures...

Thank you.

Mark

SSR440B wrote:I should have mentioned that this bike does not have an airbox, It has K&N individual filters.

That makes more sense then.

There is a small nipple at the bottom of the tank that is just an overflow. That is likely your small hose. It is usually integrated into the airbox.
Once you open the filler cap you will see the other end of the aforementioned nipple.

those two tubes dont connect to anything. They are basically tubes for the overflow vent up near the filler cap. When the airbox is installed, there is a small collection area on the front of the airbox that these tubes will flow to, that part of the airbox then has a tube that attaches to it and allows for the overflowed fuel to then flow under the bike.

Ok, I have pictures of the underside of the tank and the carburators etc.
I don't know how to attach them to this... It sounds like the two nipples on the bottom of the tank used to connect to the airbox which has been replaced with filters. There are also 2 smaller hoses coming from the carbs that go nowhere. Or more accurately, I don't know where they go. I have pics of these also...
Mark
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I suppose since I don't have the airbox, I should connect hoses to the nipples and run them back to the swingarm area with the others. Yes?
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Sure you can run lines if you want, I never did, never had an issue. Just dont overfill your fuel, or fall over and you should be okay

I am putting a basket case back together for a friend so I probably won't ride it and I think he is planning on selling it as soon as I get it back to him.
I still have 2 lines/hoses on the carbs to deal with and an additional hose that attaches to the 2 solinoid valves. I believe one of the hoses from the carbs is just a vent. The other ? And I don't know what function the solinoids serve?? Then fuel it and start it. Oh yeah, I need to install a battery too. I am close.
Mark
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MC21 carbs each have a vent and each have air jet tubes. Also there is one fuel line...

When the carbs are installed on the bike and your looking down on the carbs, the vents are on the right sides of the carbs and the air jets are on the left side of the carbs.

I beleive Andy has a diagram in the tuning section outlining the carbs...

I will look there Thank you!
A photo of an assembled bike, with the tank and airbow off, would help.
Mark

Workshop: MC21 air correction plumbing.

I've said it before, and will no doubt say it again... there isn't much you can't find on the site if you care to look for it!
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Andy.
NSR-WORLD.COM

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Andy, Thank you!
I am not near the bike now but will compare the diagram to reality when I can. I don't know if it will be exactly the same as this MC21 has K&N filters in place of the factory airbox.
Thanks again.

Rookie NSR guy; Mark

Ps. what a great web site!
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The routing of the carb tubes should not matter if you have an airbox or open carbs, you will still have the overflow tubes as well as the air jet tubes that go to the air solenoids.