Kettle Clinic

The carbs are stamped 346 22L 346 21M 346 21R

The stock main jets for your year are 105 Left, 102.5 Middle, 102.5 Right. The carb numbers do actually relate to the size of the main jets fitted from new. I have the original dealer tech bulletin which documents the change of the Left main jet to 105 after some overheating issues.

As i have two 105's and one 102.5 will it make much difference refitting them and running the bike with them or should i change one to 102.5?

I doubt you will notice the difference. It's a tad richer, but should be OK. Main jets are quite cheap to buy from Motocarb if you wanted the correct size. Suzuki did swap and change the main jets a number of times with the 550. Each time they got bigger.

Paul

Thanks for all the info guys been a great help

Just having a a quick check on the carbs running a bit erratic and engine noise changes a the motor warms up.

It's a GT550 "L" i can remember replacing the main jets,needle jet & jet needle and also the pilot jets but that was 20yrs ago
Just checked the carb specifications for the "L" and they differ slightly
Couple of questions guys
1.... i'm running 30 pilots spec states 25 will this be ok
2.... the needle jets have a square with 2.0 stamped on them spec states P-0 anyone know of these needle jets

The main jets are as stated R&L 97.5 and C 95

It's an age thing can't remember where i purchased the replacement jets

Cheers
Dave

In a bone stock US model L with individual carbs I found 27.5 pilot jets and 192 series needle jets with O-2 on the sides and O-5 in the center.

#30 pilots are fine if it runs OK with them in. Suzuki published data saying O-5 was spec but that's not what the parts book said and not what I found in a set of J carbs. Maybe that was just the cold wet UK models...
The service manual for J/K says O-5 for all except Europe and O-2 for Europe. US Suzuki say that the needle jets in an L were P-0 and the same in an M model.

192 series needle jets are unusual in that they are very short and are tapped for Hex jets, but have a short adapter that takes large round main jets.

Later model, ganged GT550 use 172 series needle jets which take Round main jets and are almost identical to 182 series but 182 are tapped to take large hex main jets.
Mike Yeadon did some research and concluded that Italian models used P-4 size and UK came with O-9. Presumably to allow for local emissions or weather differences. Maybe the warmer Italian air ran better with a slightly smaller Needle jet.

The Suzuki Carburettor Manual published in Feb. 1974 says that later 550s were fitted with P-0 but doesn't mention which market that was for.

J-K-L parts list shows HiTops as "early" but looking at teh parts list it seems to say that J and K were the same except for some K types which I assume means they were the "later" low tops. It also shows #25 pilot jets for later K models and different slides presumably to match the lower tops.


I wonder what the Ozzie models were fitted with.

Thanks for the reply teazer much appreciated the bike was an import from the USA spent all it's early life in California happy with what you suggested about the mains and the needle jets,i do have a set of #25 pilots which i will try and the float heights were a little bit high that would explain it running a bit too rich and erratic

Many thanks
Dave

And remember that cold dense air requires more fuel to go with that extra oxygen, and rich is safer and cooler running, so don't go too lean on jets.

Anyone know the part No for the float needle GT550 "L"
Parts assembly are showing 13370-34010 but i'm assuming that is for the valve & needle combined
Only looking for needle replacement only, mine are showing a slight groove down the taper

Thanks in advance
Dave