Classic & Vintage - sekai

Found a dark red lugged, Sekai frame with
Y78 0100480 on the bottom bracket shell. Anyone know anything about it?

thanks,
adam

Hey I have a red one also. Its a Medialle.A forum member says its a mid 70s bike assembled in Manitoba by Native Indians to circumvent canadian duties imposed on Japanese imports.Cdnpgt another member recently picked one up. Mine rides like a cadillac very smooth and nimble. I think you will enjoy your find. Take care and merry Xmas.

Are you serious? That's pretty cool.
It doen't seem to be a really high quality frame, but the assembled in canada by natives thing is interesting.
Does your frame look like this:
http://img527.imageshack.us/img527/1184/sekai13yy.jpg
http://img527.imageshack.us/img527/7146/sekai20qd.jpg

Sorry my mistake mines a SEKINE, it was late last night got excited thought we had twins. Thats the story on mine. TMar is the guy who knows this stuff.

Sekai was a well built Japanese brand. Easily confised with Sekine. Based on the appearance and serial number, I'd guess it's late 1970s (1978?). The lack of a tubing decal and what appear to be stamped dropouts suggests that it is one of the lower end frames, but these were still very nicely manufactured.

I do have a couple Sekai catalogs back home, but right now I'm on vacation for a couple of weeks and cannot access them. If forum members cannot provide additional info, PM or e-mail after Januaery 07 and I may be able to provide some further info.

I have, in the past, also searched the web for info on Sekai frames. The link given by Chuckk above to yellow jersey is one of the best. I have a Sekai 4000 that I bought in 1978 from the Yellow Jersey bicycle shop in Madison. It was and is a great bike. Mine is blue, but otherwise looks like the red frame. Your pictures do not look like my frame: no chromed lugs, stays, or forks.

Thanks for all the info everyone. Perhaps when T-Mar returns from vacation, I can get a better idea of what model I have exactly, but it certainly looks like it's a lower-end model.

I've been looking for a cheap frame to build up into a singlespeed. Does it make sense to put the time/effort into building up this old Sekai frame? Anyone have any advice? Will the the BB shell/head/seat tube be compatible with a wide range of components? How difficult is it to find a suitable fork for something like this?

Ah, the other thing is - is the classic/vintage thread the wrong place to be discussing a SS build?

Thanks in advance,
adam

The decision to build will depend on the amount you are prepared to spend. Fortunately, the frame will have English threading, so compatibility should not be a problem. Given the age and level, I wouldn't be suprised if there would not be too much trouble finding period correct components.

Adam, I have just returned from holiday and have taken a look at a Sekai catalog from the late 1970s. The seat tube and head tube decals match, so the era appears to be correct. Based on the stamped dropouts and single braze-on for the rear derailleur cable stop, the frame is limited to three models, the 1000, 500 & 400. These are the 3 bottom models in the lightweight line-up.

Fortunately, the Sekai specs are very complete and we can futher segrate the models based on seat tube diameter. The 1000 uses Tange, hi-tensile, single butted tubing and employed a 26.2mm seat post. The 500 and 400 use Tange, high carbon, plain gauge tubing and used a 26.0mm seatpost. 0.2mm is not much of a difference, but if you're lucky enough to have the original post, it may be marked with the size and help to distinguish which model you have.

The 400 Sport model was your basic entry level model with a steel, cottered crankset, Dia-Compe center-pull brakes and Shimano Lark & Thunderbird derailleurs with stem shifters. The remaining components were all steel. MSLP ~ $170 US.

The 500 Standard model was a slight upgrade. It had an aluminum cotterless crankset and SunTour Honor & Spirt derailleurs, but was otherwise the same as the 400. MSLP ~ $190 US.

The 1000 Sprint model had SunTour Seven derailleurs and benfitted from aluminum handlebars, stem, and hubs, but suprisingly still used steel rims. MSLP ~ $215 US.

Hopefully this has been of some assistance. If you want further details on the specs for any of these models, please let me know.

Thanks for the info T-Mar. I don't have the original seatpost (or anything else for that matter), so I guess I'll just have to live with not know which of the three models I have. I've decided the frame is too big for me anyway, so I think it's fate will be as a donation to the local bike co-op.

Thanks again for the info!

-adam

I'm resurrecting this thread with a question about another Sekai.

I found a yellow Sekai Oswego today. It appears to be a nice bike -- steel frame, forged dropouts, looks like a mtn bike frame but has bosses halfway down the fork blades for lowrider racks. Cantilever bosses and two threaded eyelets on the fork (only one set in the back, though) make me think that it might in fact be a touring bike. I couldn't find any stickers indicating what kind of tubing it has.

It has a few parts still on it, Shimano cantis w/no model name, a black high-rise stem and black flatbars with Shimano thumbshifters and mtn-style brake levers. Again, no model name on any of it, although there were some numbers somewhere. I'm not sure if any of this stuff is original.

I won't be able to see the frame again until this weekend, so if more info or photos are necessary to help with an ID then I'll post more in a few days, but I'm really curious to know more about this bike. Can anybody help?

I have a Sekai 400 as well(identical to the one posted by Dostoy) and I was wondering if someone(maybe T-Mar) would have the specs on the bottom bracket and headset.

Thanks for the info thus far!

Bottom bracket threading would be standard English threaded. The original BB would be a cup-and-cone type with a square-taper spindle. But it can be replaced with a modern cartridge BB that fits into the same standard threading.

Headset would be threaded, 1-inch ISO standard.

Just search headsets and bottom brackets on www.sheldonbrown.com, the details are all there.

I just picked up an old racing bike from a flea market today. Original decals are gone, except for the "Tange 3" ones. I've been trying to figure out what it is. Has full Shimano 600 group and tubular tires. Super light, about 21 pounds. Does this look like a Sekai to anyone. The serial number on the BB is covered up by the shift cable guides, but the first digit is an 8.

http://lh6.ggpht.com/__h_s6a95Dn4/SrUNNfL_VQI/AAAAAAAABZs/jR8D84xqvOU/s640/img_2007.jpg

thanks very much sekaijin for the info.