@ RaleighSport - I understand that you are now the "keeper" of the Sekai database, so I will add mine. I mentioned in another post the serial number isn't even close to the "Usual" format. I know that Norco bought out Sekai, but thought it was later 1980's. My bike says "Sekai" on the down tube and "Bigfoot" on the top tube near the stem. It also had a sticker that said "Made in Taiwan" on the seat tube down low as well as a very wrinkled sticker which was sort of clear with darker (I think) writing that said, "Alpine Edition". From all the date codes and the angles, fork, and components I believe it's a 1983 or 1984. I know that there came to be a Norco "Bigfoot" a bit later.
I bought this bike for $40 and it had the original cables/housings (rusted to each other inside), and other than saddle and maybe tires it was, I'm sure original. It has Dia Compe 981 "frog leg" brakes and the 281 Motorcycle levers, Victor pedals (I researched the little clover design to figure that out. I believe that Victor is now VP who sells pedals). It has Suntour early thumb shifters, Suntour Alpine Gear Tech front/rear derailleurs, a 5 speed Suntour Perfect freewheel. Sansin high flange hubs rear & Sunshine high flange hubs front. It is not lugged, but does have a great biplane fork. Cup/cone bottom bracket with asymmetric spindle I believe is 123 mm long. Brake/derailleur cables run beneath the bottom bracket in metal slots. The color is interesting, in that up close in bright light it looks metallic deep silver/grey, but at a distance it's very much sort of a mineral sea foam green. The serial # is: DSRM, then below that 50104061
Not sure how much I can put in one post, so photos to be posted in batches below.

Sekai Bigfoot photos:
http://bikeforums.net/attachment.php...hmentid=376043http://bikeforums.net/attachment.php...hmentid=376044http://bikeforums.net/attachment.php...hmentid=376045http://bikeforums.net/attachment.php...hmentid=376046http://bikeforums.net/attachment.php...hmentid=376048http://bikeforums.net/attachment.php...hmentid=376050http://bikeforums.net/attachment.php...hmentid=376051

Sekai Bigfoot Photos:
http://bikeforums.net/attachment.php...hmentid=376052http://bikeforums.net/attachment.php...hmentid=376053http://bikeforums.net/attachment.php...hmentid=376055http://bikeforums.net/attachment.php...hmentid=376056http://bikeforums.net/attachment.php...hmentid=376057http://bikeforums.net/attachment.php...hmentid=376058

I spent about 60 hours taking this bike apart (my first time ever) and removing rust, grease, new grease/bearings/adjusting, cables/housing, brake pads, etc. Only thing I changed were tires, saddle, grips. I recently bought a NOS Suntour Alpine Gear Tech rear derailleur because the other had loose rivets. I also am trying out a new handlebar/stem situation. The original was a BMX style stem with a chrome handlebar. I clear coated the bare metal spots and I will leave those as "battle scars" of life. Patina shows a little character. I put Continental Travel Contact 26 x 1.75" tires with reflective sidewalls lately. I guess I've said way more than enough. Can you tell I really like this bike?

Thank you for the added info and yes I can quite plainly see you adore that bike. Definitely a work of love, and I do find it quite pleasing to the eyes. Oh and I'm not so much the keeper as the gatherer, T-mar, Don, yellow jersey and quite a few others did most of the actual work, I just wrote it down and added/researched what I could.

[MENTION=235305]RaleighSport[/MENTION] i'm the guy who added you earlier :) i have this sekai 4000 (i guess) it was my fathers bike way back in 1980. i just want to share my sekai bike. cuz i find classic bikes beautiful! serial number is M1G30902. most parts are shimano dura-ace and has araya rims. heres some picture http://bikeforums.net/attachment.php...hmentid=385459http://bikeforums.net/attachment.php...hmentid=385461http://bikeforums.net/attachment.php...hmentid=385462http://bikeforums.net/attachment.php...hmentid=385463

Gorgeous! I hope it fits you well? Was there anything I could help you with or were you just sharing with us that beauty of a bike?

[MENTION=235305]RaleighSport[/MENTION] yep it fits me well. got butt bruises tho :D i was hoping u could help me with the serial number. how does the serials work? i'll be posting more pictures once it gets restored :)

So 1981 would be the frame manufacture year according to that. You can work out the fortnight too and figure out when in the year it was made pretty easily.

Velocivixen,

Thanks for posting the detailed pictures of your Bigfoot. I mean your bicycle. I think it is wonderful.

There is a strong connection to Norco MTBs. Many, but not all, of the Sekai MTB model names had Norco counterparts.

Serial number: Looks like DSRM, it is really DSBM. The stamping was not well executed and this happened many times with the letter 'B'. My Norco Bushpilot stamping looks the same.

DSBM = Dodsun Bicycle and Machinery Manufacturing of Taiwan. I have seen a Norco Bigfoot with a DSBM serial number.

I have not determined if the first number in the numeric part of the serial number is significant. The first number may be the year of manufacturer of the frame.

"golf club" type stem: I have not seen any early Norco MTBs with this type of stem. I have seen pictures of a Sekai Grizzly MTB with this stem and bi-plane forks.

"Alpine Edition": Norco bicycles in 1985 and 1986 had decals in the middle of the seat tube, that said what Series they were: Racing, Touring, Sports, Mountain, and possibly others. The MTBs that I have seen are all Mountain Series.

Sekai bicycles of this period also had a seat tube decal but I have never seen pictures of enough detail to read them. "Alpine Edition" makes sense for MTBs.

I am glad to hear that you like the bike. When I found an old Norco Bushpilot in a dumpster I knew it was not valuable, but it had some unique things: bi-plane forks. I had to save it and fix it up.

[MENTION=205648]Hummer[/MENTION] - that's awesome information! Thanks so much for finding all that out and sharing. I think mine is somewhere around 1984, give or take a year or maybe 2. I kept the quill stem/handlebar, however replaced it with a Kalloy Mountain riser silver handlebar to get the bars up higher. I searched high & low and decided to try the Civia "Aldrich" handlebars in silver.

Universal Cycles -- Civia Aldrich Handlebar

The new stem & handlebars change the look a little, but it's not detracting IMO. I changed out the Panaracer Paselas for Continental Travel Contact tires - smooth down the center with slight knobs on the sides, along with sort of a brownish markings on the sidewalls.
Anyway, your information is enlightening. If the first number is a year then that could be an '85 for mine.

this site might be helpful to some in dating parts

Date of Manufacture of Bicycle Components can be used to date a bike: component dating

i don't know how accurate they are tho.

Well that's interesting.. Hummer's a Sekai owner. I hope you crack that DSBM serial system and you even yet again taught me a couple details about Sekai that I did not know are you sure you're not T-mars sock puppet? ;)

Sekai
 

Those really are some large baskets
Just home with it

http://i228.photobucket.com/albums/e...pszhbqeaph.jpg

http://i228.photobucket.com/albums/e...psgflh4jnw.jpg

http://i228.photobucket.com/albums/e...psuizarqyf.jpg

http://i228.photobucket.com/albums/e...ps0ubvd2c7.jpg

http://i228.photobucket.com/albums/e...pspwbgtgsz.jpg

http://i228.photobucket.com/albums/e...psqcz6eqjy.jpg


http://i228.photobucket.com/albums/e...psbrjy3ojv.jpg

I am very privileged to still be in contact with T-mar, and I am even more privileged to share his wisdom with you all (with his permission of course). @Hummer @Velocivixen I think you both will appreciate this.

Updated the serial info on the front page to add the DSBM system.

Awesome looking! So how big is that front tire? I'm curious just how much clearance you got there!

[MENTION=250607]kc0yef[/MENTION] - nice Sekai. Do you know what year it is? Have any updated photos?

I don't see any updated pictures of your bigfoot... quid pro quo!

Your frame was built in 83, putting the odds as it is an 84 model.

who knows markings are gone sides are strips of cotton we'll see when I get some fresh tires on it

[MENTION=250607]kc0yef[/MENTION]- I thought I'd put some "cleaned up" photos on this thread earlier. Here's a recent one of it. I'm not planning on painting it or anything. Just leaving as is regarding the paint. http://bikeforums.net/attachment.php...hmentid=387495

You did but your picture is OLD two day old mine are less than 24 hours lol

[MENTION=250607]kc0yef[/MENTION] - yes, by your standards it is old. ;) I'm just eager to see yours once you've had some hands on with it. It's exciting for me to see them come alive.

Just got my 2500 back from paint

http://i228.photobucket.com/albums/e...pszn9ozjre.jpg

http://i228.photobucket.com/albums/e...psqwfqtbj9.jpg

[MENTION=250607]kc0yef[/MENTION] - your 2500 looks great! Did they use liquid paint? Looks like the fork tips got chromed too. Yes?