Help me identify my vintage Bridgestone - from the 70s or 80s?

[MotorCityCobra]

Hello. Today i bought myself a vintage Bridgestone for about 200$. It is a Suntour Power gearsystem/shifters and on the bike it says "Tested Finest Bicycle With Precision Mechanism".

What year is this bike from, and is it handmade? I think its from the late 70s.

https://imgur.com/a/GrKxIsQ

Another issue/question: when i push down the left gear shitfer, the chain on the bike comes off. This happened 4-5 times. How to solve this issue?

[MotorCityCobra]

Spotted the serial number after cleaning the bike.
The number is: G(7 or Y)80380. Does the 80 at the end mean the bike is from 1980?

[Jesper]

(06-03-2020, 03:40 AM)MotorCityCobra Wrote:  Hello. Today i bought myself a vintage Bridgestone for about 200$. It is a Suntour Power gearsystem/shifters and on the bike it says "Tested Finest Bicycle With Precision Mechanism".

What year is this bike from, and is it handmade? I think its from the late 70s.

https://imgur.com/a/GrKxIsQ

Another issue/question: when i push down the left gear shitfer, the chain on the bike comes off. This happened 4-5 times. How to solve this issue?

(06-03-2020, 12:34 PM)MotorCityCobra Wrote:  Spotted the serial number after cleaning the bike.
The number is: G(7 or Y)80380. Does the 80 at the end mean the bike is from 1980?

Welcome MotorCityCobra!

I don't know how Bridgestone serialized their bikes. It may very well be that that first or last "80" is a date code; however it could also be that the first "8" is a date code of the last digit in a year (ex. 1978). The "G" may also be a date code itself or in combination with the numbers. You may be able to research that number, but it is usually a hit or miss endeavor.
Personally, I would check the components for date codes on them. The "SR"/Sakae Ringyo (crankset) should have a date code on the inside of the arm; generally a two digit number (year) followed by a letter (month). The crankset is of a low end quality; the ring "fixing bolts" are not flush to the ring/spider, and the large ring integrated with the spider is low end design; there were many versions of "APEX 5" cranksets of higher quality. These cranks are more likely to be found on an entry level sport/recreational or touring bikes; this is also typified by the dual eyelets at the front and rear dropouts for mounting fenders and racks. The Sun Tour components also have date codes of two letters (year/month). The frame design indicates a mid-late 70's bike, and components more late 70s. It still may be that this is a 1980(s) bike, but was fitted with parts from the previous year or two (not an uncommon practice).
The price you paid wasn't horrible if EVERYTHING is in proper working order and you got NEW OR VERY GOOD condition tires and cables with it; but that being said it really isn't much of a collectible (it would not be considered a "handmade" bike), although it should make a decent rider once properly set-up and adjusted. I probably would put it more in the range of $100 if I was buying it, as there are many higher quality Bridgestone bikes out there. If tires are really good, that is an approximate $30-$80 (can easily go higher) savings right there depending on what level of tire you buy; cables are usually fairly cheap.
As far as the front derailleur throwing the chain off the ring, it is more than likely caused by the improper adjustment of the "low" limit screw which can be screwed in a little more to keep the derailleur cage from travelling too far past the chain ring; the "high" limit screw should also be checked to ensure that it doesn't do the same thing on the large ring. I would also check these same adjustments for the rear derailleur; especially on the wheel side due to there being no "spoke protector" guard! If you are not "bike mechanically" inclined you may want to bring it to a reputable shop (or experienced friend) and have it done for you; it should take less than 10 minutes, and be a low cost fix (like $10 or so; $20 is high in my opinion). Also, you may want the shop to go through the entire bike and tune it up (all bearings cleaned/repacked/adjusted, etc.), certainly a longer maintenance endeavor, and costing a fair amount even if no parts are replaced.
Hope I've helped some; overall you've got a good bike that can last for another 40 years with proper care/maintenance.

Take care,
Jesper

[MotorCityCobra]

(06-04-2020, 02:38 AM)Jesper Wrote:  Welcome MotorCityCobra!

I don't know how Bridgestone serialized their bikes. It may very well be that that first or last "80" is a date code; however it could also be that the first "8" is a date code of the last digit in a year (ex. 1978). The "G" may also be a date code itself or in combination with the numbers. You may be able to research that number, but it is usually a hit or miss endeavor.
Personally, I would check the components for date codes on them. The "SR"/Sakae Ringyo (crankset) should have a date code on the inside of the arm; generally a two digit number (year) followed by a letter (month). The crankset is of a low end quality; the ring "fixing bolts" are not flush to the ring/spider, and the large ring integrated with the spider is low end design; there were many versions of "APEX 5" cranksets of higher quality. These cranks are more likely to be found on an entry level sport/recreational or touring bikes; this is also typified by the dual eyelets at the front and rear dropouts for mounting fenders and racks. The Sun Tour components also have date codes of two letters (year/month). The frame design indicates a mid-late 70's bike, and components more late 70s. It still may be that this is a 1980(s) bike, but was fitted with parts from the previous year or two (not an uncommon practice).
The price you paid wasn't horrible if EVERYTHING is in proper working order and you got NEW OR VERY GOOD condition tires and cables with it; but that being said it really isn't much of a collectible (it would not be considered a "handmade" bike), although it should make a decent rider once properly set-up and adjusted. I probably would put it more in the range of $100 if I was buying it, as there are many higher quality Bridgestone bikes out there. If tires are really good, that is an approximate $30-$80 (can easily go higher) savings right there depending on what level of tire you buy; cables are usually fairly cheap.
As far as the front derailleur throwing the chain off the ring, it is more than likely caused by the improper adjustment of the "low" limit screw which can be screwed in a little more to keep the derailleur cage from travelling too far past the chain ring; the "high" limit screw should also be checked to ensure that it doesn't do the same thing on the large ring. I would also check these same adjustments for the rear derailleur; especially on the wheel side due to there being no "spoke protector" guard! If you are not "bike mechanically" inclined you may want to bring it to a reputable shop (or experienced friend) and have it done for you; it should take less than 10 minutes, and be a low cost fix (like $10 or so; $20 is high in my opinion). Also, you may want the shop to go through the entire bike and tune it up (all bearings cleaned/repacked/adjusted, etc.), certainly a longer maintenance endeavor, and costing a fair amount even if no parts are replaced.
Hope I've helped some; overall you've got a good bike that can last for another 40 years with proper care/maintenance.

Take care,
Jesper

Thank you very much Jesper for a great and helpful feedback. I appreciate it. I will be taking the bike to a bikestore in order to tune it up and fix the gearing. I will be visiting this forum on the regular as i will be buying more vintage bikes in the future. Take care!

[Jesper]

(06-04-2020, 06:11 AM)MotorCityCobra Wrote:  

(06-04-2020, 02:38 AM)Jesper Wrote:  Welcome MotorCityCobra!

I don't know how Bridgestone serialized their bikes. It may very well be that that first or last "80" is a date code; however it could also be that the first "8" is a date code of the last digit in a year (ex. 1978). The "G" may also be a date code itself or in combination with the numbers. You may be able to research that number, but it is usually a hit or miss endeavor.
Personally, I would check the components for date codes on them. The "SR"/Sakae Ringyo (crankset) should have a date code on the inside of the arm; generally a two digit number (year) followed by a letter (month). The crankset is of a low end quality; the ring "fixing bolts" are not flush to the ring/spider, and the large ring integrated with the spider is low end design; there were many versions of "APEX 5" cranksets of higher quality. These cranks are more likely to be found on an entry level sport/recreational or touring bikes; this is also typified by the dual eyelets at the front and rear dropouts for mounting fenders and racks. The Sun Tour components also have date codes of two letters (year/month). The frame design indicates a mid-late 70's bike, and components more late 70s. It still may be that this is a 1980(s) bike, but was fitted with parts from the previous year or two (not an uncommon practice).
The price you paid wasn't horrible if EVERYTHING is in proper working order and you got NEW OR VERY GOOD condition tires and cables with it; but that being said it really isn't much of a collectible (it would not be considered a "handmade" bike), although it should make a decent rider once properly set-up and adjusted. I probably would put it more in the range of $100 if I was buying it, as there are many higher quality Bridgestone bikes out there. If tires are really good, that is an approximate $30-$80 (can easily go higher) savings right there depending on what level of tire you buy; cables are usually fairly cheap.
As far as the front derailleur throwing the chain off the ring, it is more than likely caused by the improper adjustment of the "low" limit screw which can be screwed in a little more to keep the derailleur cage from travelling too far past the chain ring; the "high" limit screw should also be checked to ensure that it doesn't do the same thing on the large ring. I would also check these same adjustments for the rear derailleur; especially on the wheel side due to there being no "spoke protector" guard! If you are not "bike mechanically" inclined you may want to bring it to a reputable shop (or experienced friend) and have it done for you; it should take less than 10 minutes, and be a low cost fix (like $10 or so; $20 is high in my opinion). Also, you may want the shop to go through the entire bike and tune it up (all bearings cleaned/repacked/adjusted, etc.), certainly a longer maintenance endeavor, and costing a fair amount even if no parts are replaced.
Hope I've helped some; overall you've got a good bike that can last for another 40 years with proper care/maintenance.

Take care,
Jesper

Thank you very much Jesper for a great and helpful feedback. I appreciate it. I will be taking the bike to a bikestore in order to tune it up and fix the gearing. I will be visiting this forum on the regular as i will be buying more vintage bikes in the future. Take care!

Happy to help, I've been riding/rebuilding bikes for 40 years. Presently getting ready to restore a '30s French race bike. Just finished an early '70s Swedish ride. There are a lot of things to check regarding value and pricing; one component can often be worth the entire price of the bike if somewhat rare and/or in pristine condition. If you're buying to collect than size/fit won't matter much, but I like to ride what I buy so I try to find a frame of reasonable size depending on use (racing, touring, commuting, etc.). Although I don't have many Japanese bikes, they are in general of very good quality both frames and parts.
If you do plan on getting more bikes, it would behoove you to learn about maintenance/repair, and buy some basic tools specific to bikes. Tools are not overly expensive and save you their cost with only a couple of uses, and most bike work is not complicated or time consuming. I would check for a bike shop/co-op/collective that sells used parts, I have saved thousands of dollars that way. Ebay can be rough going and higher priced, and Craigslist although good prices can be down right weird at times. Check this site for work tips and deals on parts.

Take care,
Jesper

Feel free to ask questions of me via PM mail.

[MotorCityCobra]

(06-04-2020, 04:05 PM)Jesper Wrote:  Happy to help, I've been riding/rebuilding bikes for 40 years. Presently getting ready to restore a '30s French race bike. Just finished an early '70s Swedish ride. There are a lot of things to check regarding value and pricing; one component can often be worth the entire price of the bike if somewhat rare and/or in pristine condition. If you're buying to collect than size/fit won't matter much, but I like to ride what I buy so I try to find a frame of reasonable size depending on use (racing, touring, commuting, etc.). Although I don't have many Japanese bikes, they are in general of very good quality both frames and parts.
If you do plan on getting more bikes, it would behoove you to learn about maintenance/repair, and buy some basic tools specific to bikes. Tools are not overly expensive and save you their cost with only a couple of uses, and most bike work is not complicated or time consuming. I would check for a bike shop/co-op/collective that sells used parts, I have saved thousands of dollars that way. Ebay can be rough going and higher priced, and Craigslist although good prices can be down right weird at times. Check this site for work tips and deals on parts.

Take care,
Jesper

Feel free to ask questions of me via PM mail.

Thank you very much. I will stay in touch as i want to get information and your thoughts on future bikes as well. I have been trying to get into maintenance/repair, but i am really bad at it! Will try to get better though.