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250 Nighthawk [message #298877] Wed, 24 January 2018 18:37 Go to next message
Gragson is currently offline  Gragson   United Kingdom
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Howdy folks.

I'm picking up a 91 250 Nighthawk tomorrow which has not run for about 5 years, 47k on the clock and has been left outside..
Bit of a risk as I have only seen pictures of it and was assured it was running prior to being laid up. Took a punt and got it for £400 - could be a mistake but I'm feeling lucky..
I know this is hardly an exotic nor exciting bike, but I fancied something I can jump and hoon around on, have 2 bigger bikes but not very good to just pop to the shops on etc.

Intention is to mechanically commission and keep standard (and keep it) I have not read anything to particularly to watch for other than falling into a coma while riding as they are so painfully slow, but if anyone knows of anything I should check as a priority on this CB I would appreciate it Thumbs Up

I'm not too bad on the spanners, but invested in a Haynes on impulse and wish I hadn't as I now see you can get Honda service manuals in the states for about the same.

I will be back to post with some pics and to bore you into unconsciousness on this thrilling journey Laugh
If you have any advice upfront on this model - would appreciate it
Re: 250 Nighthawk [message #298878 is a reply to message #298877] Wed, 24 January 2018 19:07 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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(22) Giacomo Agostini
Welcome Hi

I know what you mean about it being nice to have a small bike to jump on without too much preparation, think similarly myself and might yet one day buy another small project bike....£400 sounds like the sort of money I'd be happy to spend from off the to get me started.

I don't know much about starting bikes that haven't run in years but suspect its a check list along these lines

1) Remove carb(s), drain, clean with plenty of carb cleaner, dismantle as much as possible so your sure your cleaning out all the small jets etc
2) Drain tank...ensure not full of rust of so wash it out with clean fuel
3) Remove plug(s), clean and check for a spark when cranked a little
4) bit of oil perhaps in the spark plug hole
5) Check oil level or better still replace oil
6) Fire it up

Probably missed something important but that'd be my list of the top of my head and sure others might add some other stuff

[Updated on: Wed, 24 January 2018 19:08]

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Re: 250 Nighthawk [message #298879 is a reply to message #298878] Wed, 24 January 2018 19:24 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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In line with that sir, I think the fuel delivery from end to end will be first thing. Shame really as wanted to see if I had a going concern but will only ruin things if I try to start it without draining / cleaning and restoring fuel system. If I do the carb first I might connect a dummy tank and see if I can get it fired up to warm the oil and ship that out - or see if I have other problems...

Will try and post a picture from the add if I can work that out - cosmetically it does not look too bad, put pictures tell lots of lies
Re: 250 Nighthawk [message #298880 is a reply to message #298879] Wed, 24 January 2018 20:09 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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https://image.ibb.co/dGs51w/s_l1600.jpg
Re: 250 Nighthawk [message #298881 is a reply to message #298880] Wed, 24 January 2018 21:27 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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(22) Giacomo Agostini
looks fairly clean and tidy considering how long its been standing, I'll give you £450 for it Grin
Re: 250 Nighthawk [message #298882 is a reply to message #298880] Wed, 24 January 2018 21:28 Go to previous messageGo to next message
slaz is currently offline  slaz   United Kingdom
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(21) Valentino Rossi
Hi bud and welcome,cant help with the bike,but your defo in the right place to get it running Thumbs Up

Kermit why is everyone's photos so BIG Laugh think
Re: 250 Nighthawk [message #298883 is a reply to message #298882] Wed, 24 January 2018 21:38 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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(22) Giacomo Agostini
Slaz, that ain't big thats just about perfect size for a 1080p LCD. I've seen your resolution though and know why you think thats big Hide

[Updated on: Wed, 24 January 2018 21:39]

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Re: 250 Nighthawk [message #298885 is a reply to message #298883] Wed, 24 January 2018 22:56 Go to previous messageGo to next message
slaz is currently offline  slaz   United Kingdom
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(21) Valentino Rossi
Kermit wrote on Wed, 24 January 2018 21:38
Slaz, that ain't big thats just about perfect size for a 1080p LCD. I've seen your resolution though and know why you think thats big Hide

See i try and join in,and what do i get Smash spank Punch Get your coat Tongue Wink Thumbs Up
Re: 250 Nighthawk [message #298886 is a reply to message #298885] Thu, 25 January 2018 00:06 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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(22) Giacomo Agostini
sorry Doh

[Updated on: Thu, 25 January 2018 00:06]

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Re: 250 Nighthawk [message #298895 is a reply to message #298886] Thu, 25 January 2018 18:11 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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Not a Honda, but what the Nighthawk will be sharing a roof with. Jekyll & Hyde in the same garage Grin
The bike courier let me down so have to wait until next week for the CB Sad


https://image.ibb.co/cW3Edb/1_zps4o35ez65.jpg
Re: 250 Nighthawk [message #298898 is a reply to message #298877] Thu, 25 January 2018 19:20 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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(18) Geoff Duke
That bike has seen some Winter riding followed by very occasional cleans. Right? Wink

Given the amount of corrosion I see my first advice is to be very very gentle on fasteners. Honda's aren't as horribly bad as Kawasaki's and Suzuki's but given the conditions I'd expect more than a few frozen fasteners.
Good quality (meaning they will fit even in a decade of constant use) tools are your friends, as is a heat gun and a few ice packs or, failing that, a big old rag filled with ice cubes. And don't forget a rubber mallet. An impact driver may also help, but it's not vital.

And I am also curious to see the bearings and brake caliper. Wink
Re: 250 Nighthawk [message #298906 is a reply to message #298898] Thu, 25 January 2018 21:43 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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The guy I bought it from bought it and basically left it 5 years ago.
I think the worst quality stuff I have worked on is late 70's yam XS varieties - absolutely shocking build quality, fasteners and ally material, hoping the CB holds no fears there but it has been outside for a looong time..

Running gear is definitely priority 3 after fuel system & engine, so looking to strip forks, head bearings, wheel, swingarm bearings, full break strip etc. I know there is some pitting on the forks, I also know the ultimate fix for that is money I can't justify so will have see how bad it is, you can get away with some hokus pokus polishing but not if near the seals and a regrind and plate is not on the cards!

If compression test works out real bad and there is metal puree in the oil change/screen then there might be a change of plan - but hoping not.

Re: 250 Nighthawk [message #298912 is a reply to message #298877] Fri, 26 January 2018 12:48 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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(18) Geoff Duke
Most of those CB's were used as commuter bikes so they are mostly high mileage and often poorly kept. This extends to the engines you can find on sale both from breakers and private sellers.

I don't really want to diss these bikes, but there's a very good reason once the Bros became available on the grey import market and Transalps became cheap enough they faded into obscurity: the 52° V-twins have their weak points, but are far more reliable long term than those small parallel twins, even if abused. Just keep dumping oil into the engine and they'll keep going. Laugh

To get back to the point, I think when compression-testing one of those engines the minimal value you are looking to is 160psi/11bars. Since the bike has been sitting for years pour a spoon of engine oil (the thinner the better) into each spark plug hole before the test and let it sit for a few minutes. It will help in case the rings are sticking.
Re: 250 Nighthawk [message #298915 is a reply to message #298912] Fri, 26 January 2018 17:27 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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[quote title=Kakugo wrote Since the bike has been sitting for years pour a spoon of engine oil (the thinner the better) into each spark plug hole before the test and let it sit for a few minutes. It will help in case the rings are sticking.[/quote]

Thats a great point, I probably would have overlooked that - appreciated Thumbs Up

I ordered this cheap AGM battery last week from ebay, usually use Motobatt but being cheap to start with..
The seller is being really pedantic that I confirm exact dims of the original battery before he will post it - even tho its advertised for the CB250 Nighthawk!

Would any one have a clue what the original battery dims would be for this bike or here I could find such info?

Many thanks

https://www.ebay.co.uk/itm/Powerline-HONDA-CB250-Nighthawk-S ealed-GEL-Battery-Year-Warranty-YTX7L-BS-1/360847483991?ssPa geName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2648

Re: 250 Nighthawk [message #298917 is a reply to message #298877] Fri, 26 January 2018 18:34 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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(18) Geoff Duke
Mr Honda says the present CB250 Nighthawk battery code is 31500-GGP-901, which translates into "Battery (YTX7L-BS) (GS-Yuasa)" in the parts description. I could almost buy a Yuasa battery for the BMW at the price Honda sells it. Laugh
It's exactly the same battery as used on the widely popular SH125/150 scooter, so you can find plenty of dirt cheap ones if the need arises.
Re: 250 Nighthawk [message #298918 is a reply to message #298917] Fri, 26 January 2018 18:44 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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Brilliant, thank you very much!
Re: 250 Nighthawk [message #298924 is a reply to message #298918] Fri, 26 January 2018 22:24 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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(22) Giacomo Agostini
Nice Kawa 750 TURBO Cool

I've never ridden a turbo bike but I'm going to take two guesses

1) its scary when the Turbo comes in?
2) your probably around the same vintage as most of us on this forum given that bike and the Nighthawk possibly being your goldenage for bikes? naughty

[Updated on: Fri, 26 January 2018 22:26]

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Re: 250 Nighthawk [message #298930 is a reply to message #298924] Sat, 27 January 2018 12:10 Go to previous messageGo to next message
Gragson is currently offline  Gragson   Netherlands
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Without exception the 750 Turbo was the best Turbo of that era, like a massive 2 stroke but with torque ! Cool I've had loads of them, the one pictured I've highly modified Grin

Indeed I am of a certain vintage naughty still swinging my leg over bikes while I still can Thumbs Up (I'm not that old)

CB is turning up 2nd Feb, same day as my wifes birthday - she is sooo happy Laugh
Re: 250 Nighthawk [message #298933 is a reply to message #298930] Sat, 27 January 2018 17:58 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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(22) Giacomo Agostini
@wife loving it Laugh
Re: 250 Nighthawk [message #298950 is a reply to message #298933] Sat, 03 February 2018 01:17 Go to previous messageGo to previous message
Gragson is currently offline  Gragson   United Kingdom
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Bike arrived today, a full 2 weeks after I bought it, can't complain as a mate got it delivered for free.

I said to the guy when he handed me the keys, is the steering lock off yes definitely he said.
So the fun starts on delivery, the steering lock is not only on, it is seized. The front wheel brake calliper is also seized on.
The delivery driver is a diamond and we are both amazed that between us we can pick the bike up in the air!
Managed to unseize steering lock and get some rotation in front wheel & negotiate the torturous route to my shed. The boat anchor has arrived!!!

Beggars belief that someone would buy something and just leave it to the elements for 5 years, does me anyway..
Apart from the myriad of spiders there is plenty of straw in the bike so am waiting for the complaint from the field mouse rehousing association

Not a lot of time today, but doused switch gear, teeny bit of diesel and 3 in 1 oil mix via syringe down cylinders and left for a wee while, hooked up a battery, all light electrics working.
Hit the starter just to spin the motor nothing, not a peep (No fuel or plugs attached of course for the test)
Kill switch pin out ok, starter relay ok was a dodgy neural switch! Sorted and spun like a good un. I reckon with clean fuel and good carb delivery this little bugger will start on the button.

Got to focus on fuel & motor 1st, but if I had a todo list I might need to get SQL installed not sure XLS would handle it

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