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Makotosun

Hardware part number decoding tips... for Alan

  • MarkT
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I don't have any way to scan right now and pictures were unreadable.  I did a little bit of research on this...  the info below should apply to many nut and bolt part numbers.

The general format of these numbers is 9XXXX-XXXXX-XX

As Alan suspected in another thread, the finish of the fastener is likely determined by the last two digits of the first five.

Example, for part number 9XX01-XXXXX-00, the 01 would designate the finish/type of material.

One complication is that Yamaha superseded many nut and bolt part numbers in late 1974...  I'll identify the before and after codes.  And I don't know if Yamaha may have superseded the numbers dozens of times since then!  So this info is good up to 1974 and probably at least a few years after 1975... 

One other note is Yamaha switched wrench sizes at the end of 74...  for example a 8mm x 1.25 bolt went from having a 13mm socket size to a 12mm socket size.  10mm went from 17 to 14 socket.  12mm went from 19 to 17 socket,  14mm went from 22 to 19 socket.

Nut Finish Codes
Cadmium = 01
Chrome = 03
Black = 06
Special Material = 11 (12 on 20mm nut)
Stainless = 90

Bolt Finish Codes
Cadmium = 01 for early and standard 4t hardness bolt, 12 for later 6t hardness bolt
Chrome = 03
Black = 06
Special Material = 11
Stainless = 90

I don't have time right now but I'll try to get back to this and see if we can come up with a general decoder for the full number...  they definitely changed the numbering logic in 1975...  and I'm sure there will be exceptions.




 
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
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16 Oct 2021 09:53 #1

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Great info Thanks MarkT
16 Oct 2021 09:57 #2

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Replied by Gr8uncleal on topic Hardware part number decoding tips... for Alan

Thanks Mark, I really appreciate this.

Given time, we could probably fill in the blanks but, as I mentioned previously, I can't believe that Yamaha didn't publish their own table.

Thanks again.
16 Oct 2021 10:15 #3

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  • MarkT
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I think we might find that they didn't because there are too many exceptions that were made....  format might be good to decode 90% of the fasteners but then there's those 10% that don't fit the pattern. 

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1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
16 Oct 2021 10:33 #4

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Replied by Sneezles61 on topic Hardware part number decoding tips... for Alan

Interesting stuff here... 
I've been tinkering betwixt an old Honda and my Rt2... The threaded sizes can intermingle between them... but then the the wrench size... In my minds eye, I swear Yamaha sez, "if Honda has a 12mm head on that thread... we'll use a 13mm"..... Competition isn't bad, eh?  
Sneezles61
16 Oct 2021 11:22 #5

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  • MarkT
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Early bikes used the larger wrench sizes...  at least with Yamaha which was a VERY COOL thing for them to do for the US market.

Why?  Because when I was a kid metric tools were not easy to find.  So being able to use a 1/2", 9/16", and 3/4" standard size wrench on many of the fasteners was GREAT!  My 1964 Yamaha had 11mm wrench size on some of the smaller bolts so I could use a 7/16" wrench.

In the mid-70's, metric tools became more available...  got my first set from Sears in about 1975.
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
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16 Oct 2021 12:56 #6

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Replied by Enduro nut on topic Hardware part number decoding tips... for Alan

That's some good info! and its funny you bring this up because im sick of going to the hardware store all the time to buy bolts and such so what ive just started to do is make a list of what size bolt goes where. For example M5x0.8x30mm goes to the coil on the stator of a 75 DT250. Its cheaper and more convenient to buy 25,50 or even 100 packs of bolts off ebay then going to the local stores all the time.
16 Oct 2021 13:01 #7

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