There’s a great thread on the WUS Forum started there by ’31Jewels’, who is a master watch repairer. He is currently working on a couple of Challenge Timers (‘bullheads’) and is showing what he’s been doing to restore them, one is his own, the other a customer’s.
It’s interesting stuff and well worth a look imho so here’s a link:
http://forums.watchuseek.com/f21/citizen-bull-head-8110a-restoration-service-31-jewels-677877.html
 | sweephand on Quartz, but collectable…… |
| sweephand on The Jet Automatic |
| sweephand on Vintage Citizen Case Backs… |
 | Juha on Quartz, but collectable…… |
 | Andy on Vintage Citizen Case Backs… |
 | Dietrich Trebing on The Jet Automatic |
| sweephand on Quartz, but collectable…… |
| sweephand on The Jet Automatic |
| sweephand on Vintage Citizen Case Backs… |
| Juha on Quartz, but collectable…… |
| Dietrich Trebing on The Jet Automatic |
| Andy on Vintage Citizen Case Backs… |
Sweephand’s Vintage Citizen Watch Blog
Sweephand's Vintage Citizen Watch Blog 
Hi can any one tell me more about my citizen watch I recently got it from my grand father it was my dad’s who passed away 15jears ago! On the back it says
Citizen watch co.
Water resist
Base Metal YP
4-R00537 RW
41200803
GN-4W
Please let me know it would mean allot to me!
Hi Tiaan, thank for visiting my blog. Can you tell me what is on the dial of your late father’s watch and is it a quartz model or a mechanical one? If you could link to photos that would be very helpful (although you can’t post a picture directly here). ‘4-R00537’ is the case number, but I can’t find any reference to that to help us I’m afraid. The serial number (41200803) will help to date the watch – all I can say at the moment is that it was made after the early 1970s since it is marked ‘water resist’. ‘GN-4W’ is the case type code, and this one indicates that it is a screw on type.
Stephen
Hello
I have a 679020 bull head which has been polished and “custoised” with a nex aftermarket orange dial and orange hands. Ok not full original but instead of to try to look like , I prefered to give it a seconf life si I changed the strap for a orange leather strap and then the Watch was looking “fashion”. (Ok don’t struggle me yet!).
Anyway a second life begun for this Watch from october 1977…..
Unfortunatly, 1 hour after have been getting the new strap, I made the Watch fall..and the Crystal was broken. do you know where I can find a new glass?
Thanks for your help and understanding
Hi, and thanks for visiting my blog. Sorry to hear about the broken glass – I hope the watch is ok otherwise. The Citizen part number for the glass is 54-50440 and new crystals can be bought for this model (usually known as a ‘bullhead’). For example a company called Sternkreuz makes good quality crystals and they have one listed for this part number. The Sternkreuz catalog number for it is XMF307.878, so if you have a local watchmaker who uses that company then he should be able to get one for you. If that’s a problem then get back to me since there is possibly another option I can help with,
Stephen
Thanks a lot§. your quickness to answer is as great as your knowledge about the 8110 bullhead or not! I didn’t understand yet how to load you a picture so you could see the disaster!
I’m afraid only I can post pictures directly here – you could post a link if you have uploaded to something like Photobucket,
Stephen
Hi there any bit of info on this watch its a quarts 21 citizen its marked
C. G. P
4-650930y
31020082
61-6524
Any help on this one
Thanks
Hi Rob, thanks for visiting my blog. From the markings on your case back, your watch appears to be an automatic mechanical watch, not a quartz model. The case number – 4-650930 – indicates that it has a 6501 day and date movement which was first produced in the early 1970s. The first three digits of the serial number – 31020083 – give us a production date of October 1973. Some info on the movement can be found on page 10 of the Movement Table: http://homepage.ntlworld.com/stephen.netherwood/VintageCitizenMovementTablev6.0Secure.pdf
The 6501 is a good quality movement, which had only a short production run as Citizen focused on quartz and reduced the range of mechanical movements to a minimum.
Stephen
Hii…..
I want to know in which year my watch was made, what would be the value(cost) of the watch now. It is a gold coloured mens watch. Details of the watch……
On the front – CITIZEN QUARTZ, CQ symbol (overlapped), Japan 6031 – T62150 – KY (at the bottom)
At the Backside – CITIZEN WATCH CO. BASE METAL YF, 6031 – K00390 CK, 1 0 7 1 5 0 8,
JAPAN =) 6
Hi Siddarth – thanks for visiting my blog. I’m less familiar with the later quartz models than with Citizen’s vintage mechanical watches. There have been so many quartz watches made that it is difficult to find information about them and when they were made. I have had a couple of other people ask about watches with the 6031 movement and after a bit of research I would think it was produced in the late 1980s/early 1990s. The serial number of yours gives us a likely production date of July 1991. The model number is 6031-T62150, and the ‘>6’ marking indicates where the back should be levered off (i.e. the 6 o’clock position). ‘YP’ is ‘yellow plate’, so the watch is gold tone, over a base metal case. I resist trying to do valuations, but I would think this model will not have any great value.
Here’s a link to the relevant technical manual: http://www.watchuseek.com/archive/seikocitizen/Citizen_Technical_Manuals/6031.pdf
Stephen