1971 T350 Carb size

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vman858
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1971 T350 Carb size

Post by vman858 »

Just picked up a sweet T350. I got a GT185 and have been through it a few times. Looking forward to this.

Guy said the carb slide where sticking a bit so I removed and measured the carb side that connects to engine with the O-Ring. The inside diameter is 30mm. Book says Carb is a VM32. Is this the wrong carb? Will this work with proper jetting? I'll check the jet sizes tomorrow.

Thanks
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jabcb
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Re: 1971 T350 Carb size

Post by jabcb »

The T350 carbs have the idle adjuster in the top and those have the adjuster on the side.

Suzuki carbs have a partial part number stamped on them. The location varied. First look on the mounting flange & on the flat surfaces around the choke.

The number is the second half of the part number. The complete number will be:
13201-##### for the right carb
13202-##### for the left carb
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Re: 1971 T350 Carb size

Post by dollydog »

hi mate, standard jet sizes for the t350 should be:
vm32 mikuni
pilot jet #30
main jet 112.5
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tz375
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Re: 1971 T350 Carb size

Post by tz375 »

If the slide is 30mm, the carbs are 28mm. 32mm carbs have the same size slide as a VM34 at 35.4mm

Mikuni use the bore to define the size, and the slide is larger than the carb bore.
vman858
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Re: 1971 T350 Carb size

Post by vman858 »

The slide is 31.5mm. Slide bore is about 31.6mm. Main Jet is 120 and pilot is 40.
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jabcb
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Re: 1971 T350 Carb size

Post by jabcb »

1972 T350 right carb pic.
ImageT350-1972_0780 by jabcb, on Flickr

Partial part number for a T305/T350 left carb. The complete number is 13202-18210 which is for a 1969 T305.
ImageT305-LeftCarb_0781 by jabcb, on Flickr

32mm dimension.
ImageT305-LeftCarb_0782 by jabcb, on Flickr
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

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tz375
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Re: 1971 T350 Carb size

Post by tz375 »

vman858 wrote:The slide is 31.5mm. Slide bore is about 31.6mm. Main Jet is 120 and pilot is 40.
And yet the calipers say 30.37mm :? . What is the bore diameter close to the slide? Outlet bore is often larger than bore in the center of the carb.
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jabcb
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Re: 1971 T350 Carb size

Post by jabcb »

Those carbs are smaller than my stock carbs.

Compare the height of the carb flange to the black insulator.
Its a bit hard to see in my pic, but the flange & insulator heights match.
In vman858’s pic, the heights don’t match & the carb is smaller.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

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vman858
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Re: 1971 T350 Carb size

Post by vman858 »

Got a few more pic's for you guys. So when I look through the center of bore this is where the 32mm comes from?

Can't seem to find any stamped numbers on carb. Did find "ISO". Cheap copies? Picked up a couple of gaskets so if I get a battery maybe have it running this weekend!

Does anyone have a recommendation of Jet size if this is a 30mm carb?
Thanks
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tz375
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Re: 1971 T350 Carb size

Post by tz375 »

Image

I don't know how to best describe this, but if you look at the diagram, the nominal bore size is the diameter just in front or behind the slide. NOT the slide diameter or the bore it sits in. Not the inlet - which is much larger.

Many carbs have the outlet the same size as the bore i.e. they are parallel bored - like a straight pipe. The picture may be deceptive, but it looks as if the outlet (where you are measuring) may be larger than the diameter just in front of the slide. They call that taper bored.

If that is the case, then the carbs are probably 28mm opening up to 30mm at the outlet.

In terms of jetting, I would start with stock 350 jetting and that should turn out to be too rich but better to start rich and work down.
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Re: 1971 T350 Carb size

Post by jabcb »

The jetting depends on how the float bowl is vented to the atmosphere. Is there a tube in the float bowl that looks like an overflow?

Late T500 carbs have that “overflow” tube. Early T500 carbs are referred to as homogenous & do not have the tube. This makes a big difference on jetting.

The float bowls are vented to create the pressure drop that forces the fuel into the air flow.
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tz375
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Re: 1971 T350 Carb size

Post by tz375 »

Good point about homopressure carbs.

That set appear to have the vent above the inlet bell - similar to a set of GT750 J/K carbs, but that needs to be confirmed.
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joethebike
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Re: 1971 T350 Carb size

Post by joethebike »

If the carbs pictured are 28mm 250 carbs forget about them on the 350. I tried 28mm carbs on my 350 back in the day when I was only using it for ride to work on the assumption it might improve bottom end performance.
It was a complete failure with worse performance all round.
1972 Suzuki T350 160,000km +2 Castrol 6 Hour races
1982 Honda CX500 EC 272,700km
2005 Suzuki DL650 145,000km
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