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Discussion Starter · #1 ·
Recently acquired a 2000 Nighthawk 250 for $200. couldn't help but buy the thing.

It's in bit of a rough condition. It was dropped few times, dings and dents are everywhere. It does start right up, and everything seems to be functioning for the most part. After starting up, it sounds like the RPM somewhat fluctuates over time and the problem is if i give it throttle the bike turns off. I've played around withe the idle speed adjuster on the carb but didn't help the turning off issue. I am planning to tear the carb apart for a cleaning / rebuilding. I'm not sure if there is a leak but things are quite greasy all around the carb and air box, could certainly use a wash.

The other thing I noticed is that when the engine is running some fluid squirts out form somewhere in the bottom. I cant really find the spot. At first i thought it was fuel leaking form the line or carb. but that liquid is actually water. I noticed some droplets under the exhaust on the right, near the foot peg but couldn't make out the source... is it a exhaust leak?

Where should I start?
 

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The water is probably condensation from the exhaust. In cold or very humid
the pipes can produce a lot of water droplets or maybe even puddles.
Once the bike gets warmed up the water should stop. Most exhaust systems
have vent holes in the bottom of the pipe just to let the water out.
 

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Discussion Starter · #3 ·
The water is probably condensation from the exhaust. In cold or very humid
the pipes can produce a lot of water droplets or maybe even puddles.
Once the bike gets warmed up the water should stop. Most exhaust systems
have vent holes in the bottom of the pipe just to let the water out.
I’ll run it and warm it up see what happens. Carb rebuild might solve the throttle issue.
 

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$200 for a complete bike that sort of runs isn't bad these days, good score.

I picked up my basket case 250NH with title for $200 then a few months later traded an electric winch I had gotten for free for two more incomplete parts bikes.
(no bodywork, seats or tanks, bent forks)

Let me know if you need any parts.
Cheers.
 

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I just reread your original post, are you using fresh gas, checked plug gaps are correct and cleaned out the float bowl of any gunk or crap?

If it'll run on choke but won't rev it could simply be blocked jets. They're cheap so you may want to order up a set one size larger than stock, soak your old jets in a little glass jar of carb cleaner and leave it in a sunny spot with a lid on and give it a shake now and then. The carb cleaner will start to change color when the junk in your jets starts to dissolve, it might take a while.
But Honda likes to sell bikes lean running bikes, you may be happy with jets one size up from stock.

Stockers are in the diagram and list numbered as:
33 main jet #110 99101-GHB-1100
And
34 slow jet #35 99103-KR3-0350

https://www.partzilla.com/catalog/honda/motorcycle/2000/cb250-a-nighthawk/carburetor

And you can get other sizes here: (and many other places)
Jets R Us Honda CB250 2004 main jet slow air pilot kit

I'll be following your progress with great interest.
 

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Discussion Starter · #6 · (Edited)
Thanks for the part numbers.

So far it doesn't do anything with with choke on. starts with choke off fine. as soon as i pull choke on it dies. Honestly I didn't get a lot of time to work on this yet. Michigan just hit its first 70° so planing to get on this soon. Is there a build thread somewhere to just post photo of a bike and post progress?

My first bike is a 78 cb125s and I wanted to highly personalize it. but everything was original and needed simple cleaning, felt awful about chopping it up. So i decided to keep it in one piece. For this whole reason I decided to pickup this beater nighthawk.

(I was the guy interested in the 2-1 exhaust by the way)
 

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You can start a thread in the Project Log section to document what you're doing and progress along the way. With a few more posts you'll be able to add a signature line with the bike and a link to the Log if you wish
 
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