Topic: What were orig tires for US model CB750A, 77'?

[duke]

Hi folks,

New member here from the US.  I see in the SOHC4 documents the stock tire types, but were these the same for every model CB750A made, regardless of country?  I just picked up a 77' with 1000 orig miles and am trying to find out if the tires on them are originals.  Any help appreciated.

tks,
duke

[05c50]

I have an original sales brochure for a 750A and all it says about tires is "Front, 3.50H19;  Rear, 4.5017A" It doesn't mention any brand.

.............Paul

[JBMorse]

My cb500 says what it had on the little sticker on the rear fender, along with the recommended psi levels.  Did you look there?  I forget exactly, but mine had a bridgestone listed.

[Spanner 1]

I think OP wants to know if the tires on his bike now are the original from the Dealer tires.... the tires should have a date stamp on them, look for the DOT stamp and look at the #'s, look both sides of the tire, one DOT stamp will have 4 extra #'s... these are the date stamp.
Example 2377 would be the 23rd. week of 1977, neat, huh!

[octalz]

My '77 750A has a sticker on the rear fender with all the factory tire info on it.

Front:
Bridgestone S21F2
Dunlop F6

Rear:
Bridgestone S21R2
Dunlop K87 Mark II

I also have a tech manual that lists both combos as original for '77 cb750A

[srook]

Spanner
The date codes for tires older than the year 2000 are 3 digit codes.  Something like 337 could be the 33rd week of 1987, 1997 or possibly 1977.  I'm not sure the code was used in the 70s and before.  The 1990s codes may have a triangle next to them indicating 1990s not 1980s or they may not.  It is hard to date motorcycle tires.  Either way you shouldn't be using tires that are older than 10 years from the date code according to the U.S. DOT.
Now that is out of the way, I have ridden on tires from the seventies and they do not instantly lose grip and fall apart.  Sure they aren't really safe but they will stay intact if you don't push them.  If its a cost issue then they should be the first thing you replace but they won't kill just because they are old.  You may kill you if you go too fast and try to corner like Ben Spies.
Scott

[Spanner 1]

Ooh!, I did not know that!

[duke]

Thanks guys!  Exactly what I needed.  Yes, I'm concerned about them being too old and dangerous.  They do look like they are perfect condition though.  Bike only has 1000mi and stored indoors.  If they turn out to be orig, I will replace them just to get a warm fuzzy.