1970 Suzuki T250-ll Carb Specs Question

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Syd
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Suzuki 2-Strokes: 72 T500J, 72 Kaw H1-B, 71 CB750 K1, 67 A7SS

1970 Suzuki T250-ll Carb Specs Question

Post by Syd »

Can anyone help me with the following information relating to the correct carb specs (jets etc) for a 1970 Suzuki T250-ll (Street Scramber model). The info shown on the Japanesebikes.com website under "Service Data Manual for 1970 Suzuki models" shows the main jet as #110 whereas my motorcycle which seems 100% original has #113 main jets. Is this correct or is #110 main jet correct?

The service data manual does not state what the needle jet size is, however my T250-II has #02-164 stamped on the needle jet - is this the correct size needle jet for the 19670 Suzuki T250-II?

The jet needles are correct at #5CN3-3 Clip, pilot jets are correct at #25 and the valve seats are correct at #2.5

If anyone can help me with this, that would be much appreciated, cheers.
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jabcb
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Re: 1970 Suzuki T250-ll Carb Specs Question

Post by jabcb »

Service bulletins are here: https://ozebook.com/compendium/techbuls/index.htm

Service Bulletin Specification-11 has the 1970 carb for 26mm specs: https://ozebook.com/compendium/techbuls ... 010-14.pdf
main jet: 110
needle jet: O-2
jet needle: 5CN3-4
pilot: 35
Service Bulletin Specification-6 has the 1971 specs for 26mm carbs: https://ozebook.com/compendium/techbuls ... %206-9.pdf
main jet: 110
needle jet: O-2
jet needle: 5CN3-3
pilot: 25

Suzuki had some model variations in different markets, so your regional model may differ a bit from the specs.
Suzuki also varied jetting a bit from year to year, even when they didn’t otherwise change the motor — often because they found the bikes ran a bit better with the tweaks.

Take a closer look at your needle jet. The “164” may actually be the Mikuni logo, or some other logo.
Looks like you have the tweaked 1971 jetting. Perhaps some prior owner upped the main jet a bit because his particular bike ran better, or maybe a 113 main jet was a Suzuki regional spec.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Syd
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Suzuki 2-Strokes: 72 T500J, 72 Kaw H1-B, 71 CB750 K1, 67 A7SS

Re: 1970 Suzuki T250-ll Carb Specs Question

Post by Syd »

Thanks for your help Jabcd - really help info.
Syd
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Posts: 212
Joined: Tue Aug 02, 2011 8:25 pm
Country: New Zealand
Suzuki 2-Strokes: 72 T500J, 72 Kaw H1-B, 71 CB750 K1, 67 A7SS

Re: 1970 Suzuki T250-ll Carb Specs Question

Post by Syd »

Hi Jabcd,

I found this link in the UK which shows Suzuki part number 09494-00074 needle jet replaced by a pattern needle jet number 02-164 which is what I have so maybe this is all correct then?

https://www.suzytwo.co.uk/ourshop/prod_ ... TTERN.html
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