The seat looks good.  The o-ring on the seat looks good.

The OEM seat has a .108” hole.  It’s only .009” bigger than the new seat.  Such a small difference, no big deal, right?  Actually, that’s a pretty big deal.  The cross section on the new seat is 19.5% less than the cross section on an OEM seat.  I suspect the smaller hole will result in a dramatic reduction in fuel delivery.   Another one-way ticket to meltdown.

Constant velocity carburetors (the kind with the big diaphragm on top) use a slide assembly that is raised and lowered by air flow through the venturi.  Your throttle cable is not connected to the slide.  The slide goes up and down based on air flow.  Air flows when the intake valves are open; and stops flowing when the intake valves are closed.  So, when you are cruising at 3500 rpm, air flow through your carburetor starts and stops 1750 times per minute.  That’s about 30 cycles per second.  If you have ever looked in the throat of one of these CV carbs while the engine is running, you probably noticed that when you increase the rpm the slide starts bouncing up and down.  It’s constantly buzzin.  Soft brass needles and needle jets don’t hold up well.  I believe that is why the OEM carb uses a stainless-steel needle jet with an anodized aluminum slide needle.  They don’t want these critical components wearing out prematurely.  It’s an emissions thing, gotta last.

So, we have a brass needle jet.  It might wear out kinda fast.  No biggie, the whole kit is only $10 bucks.  Just plan on changing it out a little sooner.  How about the dimensions?

OEM needle jet orifice is .121”.  The new needle jet orifice is .119”.  Pretty close.  Only a .002” difference.

Let’s look at the slide needle.  It’s identified on the illustrated parts breakdown as “piece 10, needle (5C17), P/N 13383-24C40, $14.37”.  The OEM needle is anodized aluminum and has a single groove for the locating clip.  The new kit needle is brass and has three grooves for the locating clip.  The soft brass material is a bummer, but having the additional adjustment afforded by the two extra grooves is nice.

With the caliper set to .105”, you see that the new brass needle moves down just a bit more in relation to the the stock needle, indicating it would be a bit richer than the stock needle at about half-throttle.

And by .115”, the brass needle is runnin away from the stock aluminum needle.  This indicates that the new kit needle would be a lot richer at very small throttle openings.

A new carburetor (13200-24C42) costs $573.54.  If you substituted genuine Suzuki parts for the items provided in this kit, it would set you back about $203 and you still would have the same old TEV and slide assembly.

The only kit I could find on-line that looked like it might have a good chance of working was the Parts Unlimited kit (1003-1386) offered by Dennis Kirk (currently out of stock).  This is a picture of the parts in that kit.  The material list states that the main jet is a #145 and the pilot jet is a #52.5 (always a good sign when the sizes comply with specs).  Note that the mixture screw looks correct, and the slide needle is anodized aluminum, and the gasket looks like actual composite gasket material (not plant fiber).  This kit will set you back about $40 to $50 bucks.  Five times more expensive than the All About Carbs kit, but ya get what ya pay for.

One potential source looks like “powersportusa”.  They offer the Parts Unlimited Carburetor Repair Kit 1003-1386 for $41.95.  Economy shipping is $3.95.  Not bad.  If you ordered the same parts from the OEM, it would set you back about $140.  Question is, how good are these kits?  The picture indicates the parts are correct, but the proof is in the pudding.