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Re: 250 Nighthawk [message #299199 is a reply to message #299198] Fri, 30 March 2018 20:01 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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(2) BSS Racer
32 kilo vice makes light work of bead breaking, especially on little wheels like these Thumbs Up
Now, is there supposed to be a few litres of water in there? Paris/Dakar special perhaps?, water storage in case of breakdowns Laugh
I am banking on the valve, the sodden rubber edge looks promising as the culprit, hoping the same for the rear...


https://preview.ibb.co/iaR70S/IMG_2057.jpg
https://preview.ibb.co/g8Fd77/IMG_2061.jpg
Re: 250 Nighthawk [message #299200 is a reply to message #298877] Sat, 31 March 2018 07:56 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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(18) Geoff Duke
Tha's how Tiger mosquitoes got into Europe: water in tyres. Wink
Re: 250 Nighthawk [message #299207 is a reply to message #299200] Mon, 02 April 2018 17:17 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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Front wheel prepped for painting, waiting for paint to be delivered. Once scrubbed down with mild scotchbright and IPA one side of the wheel came up like new, the other does need paint tho..tyre inspected and looks fine so hoping valve replacement will sort the deflation.


Forks done and polished (very boring) speedo drive repaired, waiting for new disk and need to put final paint on guard.


Went to check valve clearance and have failed at first hurdle, I don't have the special fxxxing tool to remove the crank cap so clearly using a right size washer spacer in a set of mole grips, the bastard is not moving and I have removed some edge, appears some had been removed previously as well, so far I have heated the area a bit and tried tapping round with a punch - nothing.


Least I bugger it completely, are here any pearls of wisdom on removing a seized crank cap?


https://preview.ibb.co/k3P1fS/IMG_2086.jpg




Re: 250 Nighthawk [message #299208 is a reply to message #299207] Mon, 02 April 2018 19:45 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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(18) Geoff Duke
If you mean the cap on the crankcase cover you need to remove to rotate the crankshaft, the best tool to be used is a large, short handled cold chisel. There's no easily available screwdriver that will safely do the job and those crankcases rank somewhere between "cheese" and "boiled potato" in the Brinell Scale, so that slot will be easily turned into a mess.
As most mechanics (starting from old fashioned professional ones) either overtorque that cap or put Loctite on it in a misguided attempt to... I am not exactly sure, before using your chisel use a hot air gun to heat the area to around 100°C, then quickly cool with an ice pack or some crushed ice in a rag, then gently tap the area with a rubber mallet. It should help.
Some chisel sizes fit pretty neatly into the slot and can be turned using a wrench or even by hand and the good news is generally speaking chisels are pretty cheap. The bad news is an ill-fitting chisel will make extremely short work of that cap. Laugh
Re: 250 Nighthawk [message #299211 is a reply to message #298877] Tue, 03 April 2018 12:40 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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Yes thats the cap! Think I was being a bit too mild with the heat, was getting dissipated quickly when I checked it with an IR gun (which is about as accurate as a scud missile)
Gave it a good heating with a torch and cooled quickly as suggested. Still the bastard would not move, but was really struggling for purchase.
Ended up dremmeling the channel deeper and wider to fit 2 big washers in mole grips and finally it was on the move. I will clean up and square the new cap channel for my "special tool" Tongue

There may well have been some thread lock in there, positively overtightened, and the o ring was dust, seized also by ali oxide sitting in a field for years.
I think the ali cases come from melted down Mitsubishi zeros Grin

https://preview.ibb.co/kFmPKx/IMG_2087.jpg
Re: 250 Nighthawk [message #299212 is a reply to message #298877] Tue, 03 April 2018 13:04 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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(18) Geoff Duke
As an Öhlins technician I know said "Think about the poor bastard who'll have to undo that bolt a few years from now".
Which in this case means "Do not overtight" and "Do not use Loctite; use either grease or graphite to avoid seizing".

Re: 250 Nighthawk [message #299241 is a reply to message #299212] Tue, 10 April 2018 00:18 Go to previous messageGo to next message
Gragson is currently offline  Gragson   Netherlands
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Kakugo wrote on Tue, 03 April 2018 13:04
"Think about the poor bastard who'll have to undo that bolt a few years from now".
I will change my user name to "poor bastard" given this little rebuild RollEyes

Bit of progress, valves adjusted, were not too far out tho, front wheel and guard painted, new disk, replacement caliper and MCL fitted. Very happy with the 2nd hand complete front break, someone had looked after that one Thumbs Up back end next, lots more mouse nests

https://preview.ibb.co/dsJWSH/IMG_2119.jpg

[Updated on: Tue, 10 April 2018 00:23]

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Re: 250 Nighthawk [message #299244 is a reply to message #299241] Tue, 10 April 2018 08:47 Go to previous messageGo to next message
Yorkie is currently offline  Yorkie   United Kingdom
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(8) Moto2 GP Racer
Gragson wrote on Tue, 10 April 2018 00:18
Kakugo wrote on Tue, 03 April 2018 13:04
"Think about the poor bastard who'll have to undo that bolt a few years from now".
I will change my user name to "poor bastard" given this little rebuild RollEyes


Laugh Laugh
Re: 250 Nighthawk [message #299293 is a reply to message #299244] Tue, 24 April 2018 15:54 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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Hello, I'm after some help please..

I'm pretty near complete on this and starting to bolt everything back together, but having changed the chain and sprockets have come across dangerously worn out cush drive rubbers, to the extent that the rear sprocket wobbles on its mounting studs and the studs themselves are so loose in the cush drive rubbers they just clear the puny swingarm!

According to the "owners card" this is a late 1992 registered CB250-N Nighthawk.
I cannot find the part number on Honda EPC, it does not show the cush drives separately, and I have inquired with an on line parts dealer and they could not find a part number for them!

Any steers much appreciated.

Cheers
Chris
Re: 250 Nighthawk [message #299295 is a reply to message #299293] Tue, 24 April 2018 19:13 Go to previous messageGo to next message
Yorkie is currently offline  Yorkie   United Kingdom
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Sorry Chris, I can't help you with this but I reckon Kak will be along shortly with his wealth of knowledge Thumbs Up
Re: 250 Nighthawk [message #299297 is a reply to message #299295] Tue, 24 April 2018 22:55 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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(22) Giacomo Agostini
Could be 41241-413-781

ebay search

or

http://www.wemoto.com/bikes/honda/cb_250_nighthawk_mc24_usa/ 91-08/ and scroll to TRANSMISSION - FASTENER SPROCKETS AND CUSH DRIVES Section to see if thats the one?

http://images.wemoto.com/full/CUSH_DRIVE/10052514.jpg

[Updated on: Tue, 24 April 2018 23:00]

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Re: 250 Nighthawk [message #299298 is a reply to message #298877] Wed, 25 April 2018 00:02 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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Thats the fucker, I looked there and could not see it on their site Wall

Thanks a lot gents, will be giving them a buzz in the morning!

Pushing it out of the shed for its maiden tomorrow even with the wobbly sprocket, the new heavyweight x ring chain should keep it in check and drop the hp to about 30... eek

Thanks again Thumbs Up
Re: 250 Nighthawk [message #299307 is a reply to message #299298] Thu, 26 April 2018 22:49 Go to previous messageGo to next message
Gragson is currently offline  Gragson   United Kingdom
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Ordered the cush drive rubbers but took it for a spin around the garden for a trial. Cosmetically its still a bit challenged and I may drop the motor in the winter to give it a proper blast, but then again I probably won't - either way its looking a million times better then when I got it. There was a fair bit wrong with it and its taken longer and cost more than I had bargained for but it runs well, bit of valve adjustment, good compression, very quiet. And with all the breaks, forks, wheels renewed and overhauled it will piss past the MOT. Its a very easy little bike to work on really - a lot easier than the DFI Turbo charged dinosaurs i'm used to anyway.

£400 to buy, about the same again in mostly consumables and approx 30 hours of mostly enjoyable work doing it. It ain't worth £800 quid if I tried to sell it, but I'm really glad I have a little bike I can just jump on with a tight pair of speedo trunks, flip flops and a straw hat and terrorise the local mobility scooter users Grin

End of Nighthawk resto, now on the look out for an 18" Ransomes Marquis cylinder mower oh and somewhere to store all this shit RollEyes

https://preview.ibb.co/fFzzeH/1.jpg
https://preview.ibb.co/fzTQKH/1a.jpg
https://preview.ibb.co/d9Dgtc/2.jpg
https://preview.ibb.co/k0rZDc/3.jpg
https://preview.ibb.co/c4nkKH/4.jpg
Re: 250 Nighthawk [message #299309 is a reply to message #299307] Fri, 27 April 2018 07:50 Go to previous messageGo to next message
Yorkie is currently offline  Yorkie   United Kingdom
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Cracking job Thumbs Up Thumbs Up
Re: 250 Nighthawk [message #299311 is a reply to message #299309] Sat, 28 April 2018 00:30 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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(22) Giacomo Agostini
think your being a bit unfair to yourself with "cosmetically challenged" but looks good to me and as you say, a little bike like that is easy to hop on to potter down to the shops (or beach) without too much faffing around getting leathered up etc Thumbs Up

I've checked ebay completed sales and your probably right £800 would be borderline loss/profit territory but hard to measure the 30 hours of mostly pleasure with money so even if you did sell and loose £100, you'd still be in positive territory the way I measure these things. Its a good few years since I did something similar of which I've done 4 or 5 5-10 years back and probably only made money on one and not much at that but money and time well spent Cool

[Updated on: Sat, 28 April 2018 00:32]

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Re: 250 Nighthawk [message #299313 is a reply to message #299311] Sun, 29 April 2018 18:57 Go to previous messageGo to next message
Quazi is currently online  Quazi   United Kingdom
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(22) Giacomo Agostini
Good work fella, it's always a labour of love because you never get your money back. Grin
Re: 250 Nighthawk [message #299314 is a reply to message #299313] Mon, 30 April 2018 08:45 Go to previous message
Gearbox is currently offline  Gearbox   United Kingdom
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(15) Kenny Roberts
Not sure its about the money, sometimes its just the challenge. Another one saved from the scrap man for a few years.
Great job
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