GSXR250 GJ72A Carburetor Query

[Blabz]

Hi all,

For the last few years I've been the neglecting owner of an '87 GSXR250 (GJ72A), it never really ran all that well and never sounded too healthy.
These things have two "dual throat" Mikuni CV carbs, each carb fuelling two cylinders, below is an exploded diagram of them.

Recently I decided to put some love back into the bike and dismantled the carburetors and cleaned out the pilot jets, main jets, and inspected the slider assembly. The slide holders (Diagram Position #4) were buggered and quite loose, but for some reason stuck solid with a 90 degree rotation, obviously not ideal in the long run but it works for the minute, they're on the list to be replaced.

A few of the sliders (Diagram Position #3) also have chips in them, and appear to be damaged where the slide holder fits to them so I'd like to replace them too, while inspecting I noticed that the sliders all have a number printed on the top of them.

Both pairs of carbs I own seem to have a mix and match of them.
My spare carbs as seen in the pictures have 2x #1, 1x #3 & 1x #2
My carbs currently fitted to the bike have, 3x #4 & 1x #3

Does anyone know the relevance of the number on top of the slider?

I thought perhaps it might be a sizing difference,
or for matching which cylinder it belonged to when first assembled.

[F5 Dave]

Search me, never noticed them when trying to build a set from 3 sets. You might try polish the slide bores but don't rub the slides with anything abrasive. Blowing in the front top holes should raise the slides easily.

My next move is to remove 47,48,49,50 from diagram and check o-rings still OK. Swines of things.

[Blabz]

I had a chat to a friend who is well versed when it comes to engineering and he suggested that it's likely used for determining which casting unit it came from during production for quality control purposes.
Considering it has a single Suzuki part number and my two pairs of carbs seem to be a complete mix and match of them I think this is pretty plausible!

Search me, never noticed them when trying to build a set from 3 sets. You might try polish the slide bores but don't rub the slides with anything abrasive. Blowing in the front top holes should raise the slides easily.

My next move is to remove 47,48,49,50 from diagram and check o-rings still OK. Swines of things.

I had a quick attempt at searching your posts but no luck finding anything relevant :/
I'll have a look into the parts you mentioned and check over the O-rings, thanks for the tip!

[F5 Dave]

Not my thread. The gsxr400 one. Have one downstairs I need to get back to the owner in between trying to work on my worthy projects