That looks like a pretty decent quality bike from here! Is there a tubing type sticker?

The only sticker left is the one on the front. I added two other stickers because of parking regulations and theft prevention. Even with the rough paint (it has so many scratches and small rust spots), I've tried to maintain it as best as I can. It rides nice, shifting is super smooth, no noises. For its age, it is still very comfortable on the road! But, it needs new cables/housing, a new bar tape, and it needs new calipers (the old ones can't hold much longer as they keep swaying to one side and I can't tighten or adjust any longer. The rear derailleur is slightly bent, but works! I'm at a point that if I need to make all those changes to keep it, would it be worth to strip everything down for a paint job? There's a place in Chicago that does paint jobs (I haven't called them to get more details, but here they are: https://heritagebicycles.com/products/bike-paint-job). I appreciate any advice.

Worth it as a monetary investment? Almost certainly not.
Worth it to create your own vision of what an 80's lugged steel road bike should be? Absolutely! :)

Keeping it as a winter project. I suspect even bike paint shops are overwhelmed with work. I'm also trying to get my other one in good shape. I can only spent so much money and time on those things! I wish I had one in abundance! I'll post any update when it happens. Thanks!

A 25.4mm seat post would confirm a Sekai 500, as that is down into the plain gauge, hi-tensile steel range and the Sekai 400 and 500 were the only two models with that grade of tubeset during this era. However, the 400 was typically equipped with Shimao derailleurs and a steel, cottered crankset, while the 500 was SunTour equipped and got an aluminum, cotterless, Sugino crankset as on your bicycle. I'd expect the outer diameter on the seat tube to be 28.6mm

Sekai?!
 

The decal is not the original. Is this Sekai? Thanks



https://cimg7.ibsrv.net/gimg/bikefor...a49e3da80e.jpg
https://cimg8.ibsrv.net/gimg/bikefor...848ee3b498.jpg
https://cimg9.ibsrv.net/gimg/bikefor...02b87efe90.jpg

Your frame was manufactured by Miki of Japan in 1985. While Miki was a contract manufacturer of Sekai frames, they also manufactured several other brands. I see that you are located Indonesia so I strongly doubt that this is a Sekai brand ATB. Sekai started out as a USA brand but by 1985 had been taken over by Norco of Canada, who marketed Sekai only in the USA. While it's possible that a non-related Sekai brand existed elsewhere in the world, I haven't seen any cases of foreign market Sekai. More likely, it is some smaller, possibly local, Asian market brand that was contract manufactured by Sekai.

Sekai 4000
 

Hi all

I’ve been lurking in the background using this forum to gather information on Sekai 4000. I bought a Sekai 4000 Criterium back in the 70’s as my first racing bike. I wanted to restore my memories of this ride and bought one from a great seller in Spokane (I’m in Portland). Though this is not exactly the same as my old dark blue frame with chrome long point lugs, it will easily substitute in my mind. This frame is Tange #1 tubing and paint is in very good condition with chrome showing through the nicks. I’ll just give it a thorough cleaning and will be on the road as soon as it stops raining :) I’ll post pics once I’m allowed.

Thanks for all the data from members and i hope to contribute more in the future.

Thanks! I appreciate the information! The seat tube at the end is not 28.6mm.

BTW, the serial number is M1E30319 (1981 March build)

”BTW, the serial number is M1E30319 (1981 March build)”

Here more specifics on my Sekai 4000

Shimano 600 (Derailleurs, downtube friction shifters, HS, Crankset)
Shimano Dura Ace Wheelset with 7-spd cluster
Funky handlebars and stem

Sekaa
 

Rescued Sekai 2400 from the dump. Have cleaned it up the best I can...next will get rid of the rust. Need to find a good touch up paint for all the rust spots and knicks. 1985, Tange 900 frame. Will be turning this into my first single speed.

https://cimg4.ibsrv.net/gimg/bikefor...e8d4e65fe0.jpg
https://cimg8.ibsrv.net/gimg/bikefor...d67eb30e81.jpg

I just picked up a Sekai Racing series from Facebook marketplace last night. I 've never had a bike that was this lightweight before. It weighs about 22-23 pounds from what I can tell from my scale maybe. I'm excited to learn more about it and clean it up. I think it needs new tires, the tubes hold air well so I think I can salvage the tubes. Will post pictures soon. I've been told by a few members already this was a steal for $80. Bought if from someone that got it at an Auction and it was too small for her husband.

Serial number is M4B02087

https://cimg5.ibsrv.net/gimg/bikefor...1fc6df04a.jpeg
https://cimg7.ibsrv.net/gimg/bikefor...d73276b4b.jpeg
https://cimg6.ibsrv.net/gimg/bikefor...0667cdb46.jpeg
https://cimg9.ibsrv.net/gimg/bikefor...5f1780616.jpeg
https://cimg0.ibsrv.net/gimg/bikefor...81ffc82ac.jpeg
https://cimg2.ibsrv.net/gimg/bikefor...304dc51f4.jpeg
https://cimg4.ibsrv.net/gimg/bikefor...6a865b889.jpeg
https://cimg7.ibsrv.net/gimg/bikefor...807f83831.jpeg
https://cimg0.ibsrv.net/gimg/bikefor...74aba06413.png
Serial number M4B02087
https://cimg3.ibsrv.net/gimg/bikefor...a4593006a.jpeg
components are Suntour Superbe

Sekai 400
 

I've been fixing up this, what i presume is a Sekai 400 and was really interested in looking up the serial number but the guide doesn't quite line up for me. The serial number is Y3HC543. I'm not sure how original everything is but it's all looks period correct. would you be someone who could help point me in the right direction? the gearsets is made up of all Suntour - Honor back derailleur, Sprit front, LD 3000 stem friction shifters. Dia Compe brakes and levers. The levers have this part number on it 3403577.

Welcome to the forums. The 'C' is likely an incompletely struck '0' (zero), in which case the serial number format is consistent with Yamaguchi, a known Japanese contractor for Sekai bicycles. The serial number indicates it was manufactured during August of a year ending in '3'. Both the Honor and Spirt derailleurs were in production in both 1973 and 1983, but I don't recall seeing this Yamaguchi format on Sekai prior to 1980, so I'd be leaning to 1983 manufacture. August is in the grey region where it could be either a 1983 or 1984 model.

Sakai bike serial number M5B04526
 

I have a Sakai Bike serial number M5B04526 the previous owner told me that it was a custom made Sakai due to the large size. Any truth to this?

I've already answered your query in another thread. Please do not cross-post. See https://www.bikeforums.net/classic-v...ssistance.html

Need help to ID a Sekai road bike; Model 4000, 5000, or ?
 

Hello all,

I purchased a 1983 silver-gray Sekai road bicycle (Serial # M3C05057) last Sunday at a local flea market here in Southeastern Massachusetts for $90.00. I knew little or nothing about the Sekai brand but I could see immediately by it’s lines and build quality that this is a special machine.

I searched the net and found your forum and read-up on Sekai. At first I thought it was a model 4000 because it has Tange Champion #2 tubing, but because it has no evidence of a model number on the frame, and 41cm stays I began to think this is either a 5000 model or a custom build. The frame is fully chromed under the paint and has a Tange Levin headset and cast crown arguing in favor of it being a 5000 model, but no evidence of fork blade tubing labels, It has Suntour Superbe Pro rear dropouts and Shimano front dropouts.

Another odd thing is that it appears to have been sold by a company called Soloped, which is the name of a bike shop in Cape Town, South Africa.

I tried to include some images here, but but as a new member I am apparently unable to do so.

It has mostly Dura-ace ax components with the derailleurs changed-out to later 600 series, Nitto aero (drilled for wires) bars, Mavic CXP-12 rims, Kashimax saddle, Kalloy 26.8mm seatpost, Gran-Compe calipers, and no-name plastic pedals.

My intent is to clean it up for now and ride it as-is, albeit with a decent seatpost and quality pedals (I already ordered a nice set of DA ax pedals) and perhaps later, have it repainted with new decals.

Does anyone have any thoughts on this bike, what model it is, or any other information that may help properly identify it?

Thank you

Nice, glad this thread re-surfaced as I don't recall seeing it before. This is one long a$$ thread and I haven't read it all nor have I looked the original links but will do so for some historical facts. I think I remember reading that the model Sekai and Sakai were one in the same. This is my Sakai bike which i really like. The entire bike is in near perfect condition (give or take a few components) and original other than the bar tape and saddle. Hope you enjoy!
https://cimg3.ibsrv.net/gimg/bikefor...77f2b6998c.jpg

Sekai was a USA brand that was bought out by Norco in late 1983, for the 1984 model year. Sakai was the Japanese house brand for Bloor Cycle of Toronto. There's no relation, other than the similairity of the brand name and, in some cases, the Japanese contract manufacturers they employed.

Maybe it's a Sekai 2700? During this era, it employed the short stays of the 5000 but used Tange #2. If Sekai was being marketed outside North America at this time, the models may not align with anything sold in the USA.

Thank you Gthomson and T-Mar for your helpful feedback. I am going to try to contact the original dealer (apparently Soloped) who sold it to see if they have any other information that I can share.

One thing I did notice is that the bike I have matches many of the frame details of a 1984 model 5000 made with Champion #1 that is shown on Mr. Gillies page.

Also, I will continue to work on uploading some images of the bike to the forum, hopefully soon.

In the meantime, I am going to take her for a ride today while the weather still allows it.

Best regards,

Thanks for clearing that up T-Mar and I knew it was the house brand from Bloor Cycle as you told me about that in the past but I thought I read somewhere the bikes (Sekai/Sakai) came from the same manufacturer in Japan but I could be wrong.

Yes, we have seen cases of common contract manufacturers for Sakai and Sekai but those contractors produced for several companies, not just Velocipede/Sekai and Bloor Cycle. Also, the Kent family reportedly conducted their own design/spec work for their Bloor Cycle house brands.

Of course, that often could result in very similar models. When designing to a price point, while trying to stay competitive with other companies and still make a profit, there was usually a pretty narrow selection of components, tubesets and frame fittings. The easiest and most profitable route was to select a standard frame design from the contractor's catalogue and oufit it with the most popular component group for the target price point. The more you deviated from the standard offerings, the higher the contractors' price.

Sekai 2400
 

Hi can you date my frame?


Serial Y0F9870

thanks!