T500j needles.

General discussion about Street two-stroke Suzuki motorcycles.

Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan

Post Reply
Steve zodiac

T500j needles.

Post by Steve zodiac »

Hello.
Am I reading this correctly?
Does the 500j have odd needles? P4 in left & p5 in the right.
If this is so. Can anyone please explain why.
And why it is only on the J model?
Your thoughts appreciated as always.
Sean.
Steve zodiac

Re: T500j needles.

Post by Steve zodiac »

Surely somebody on here must know about the T500j carb needles.
Sean.
User avatar
jabcb
Moto GP
Posts: 4241
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: T500j needles.

Post by jabcb »

The carb specs are in service bulletin Specification-6
http://www.ozebook.com/compendium/techb ... %206-9.pdf
1971: both P-5
1972: P-5 & P-4
1973—1975: both P-4

Early T500s used a paper air filter & later models used a mesh filter.
There also was a cylinder porting change, but I’m not sure of the details.

The triples had slightly different jetting for the center cylinder due to the 3-into-4 exhaust.
Am not a carb expert, so I have no insight into why different jets were used in the 72 T500.
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
User avatar
johnakay
I likes them jubblies
Posts: 2365
Joined: Wed Oct 15, 2008 11:19 am
Country: UK
Suzuki 2-Strokes: bike

Re: T500j needles.

Post by johnakay »

later models used a mesh filter.?
you mean foam.
I've had the M'GT models and they had foam no mesh.
If I wanted to make a life-long career out of
working with the mentally retarded I would
have opened a Harley Davidson Dealership
User avatar
jabcb
Moto GP
Posts: 4241
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: T500j needles.

Post by jabcb »

Correct. I meant the foam filter when I said mesh filter.
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
User avatar
johnakay
I likes them jubblies
Posts: 2365
Joined: Wed Oct 15, 2008 11:19 am
Country: UK
Suzuki 2-Strokes: bike

Re: T500j needles.

Post by johnakay »

jabcb wrote: Sun Aug 15, 2021 6:46 am Correct. I meant the foam filter when I said mesh filter.
not ta worry even I get it wrong some times.
rarely though :D :D
If I wanted to make a life-long career out of
working with the mentally retarded I would
have opened a Harley Davidson Dealership
User avatar
ConnerVT
Novice racer
Posts: 963
Joined: Wed Jan 18, 2012 8:01 pm
Country: USA
Suzuki 2-Strokes: T500R (now), T500M (40 yrs ago)
Location: North of Albany, NY

Re: T500j needles.

Post by ConnerVT »

Late to the party.

Nothing mechanical really changed between 1971 and 1973. Engine itself, intake runners, air box and filter all stayed the same.

My feeling is that Suzuki was just trying to figure out their homopressure carbs, and just couldn't get them to play nice. I've gone through several dozen combinations of jets, needles, needle jets, shimming needles, etc. and have only come up with a best compromise for how I ride. Never 100%.

I believe that's why Suzuki made the wholesale changes in 1974 - going back to a conventional atmospheric vented carb, with changes to the cylinder, intakes, and air box/filter. They just couldn't get it to work.
Post Reply