Home » General » Restores, Rebuilds and Tart ups. » 250 Nighthawk
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   
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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   
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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   
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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   
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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   
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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   
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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   
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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
Re: 250 Nighthawk [message #299244 is a reply to message #299241] Tue, 10 April 2018 08:47 Go to previous message
Yorkie is currently offline  Yorkie   
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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


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