Suzuki 2 Strokes

I saw another post on the forums about this topic but it didn’t answer my question. I have 2 Mikuni VM32SH carburetors for a T350 and I stripped the jet on top of the pilot jet (still got it out without damaging the aluminum threads) and I was wondering what the correct term is for that jet? And with other Mikuni VM carburetors they only have one jet in the idle circuit, so is it possible to only have 1 pilot and 1 main jet on the VM32SH? If not, how would it run without it? And is that extra jet necessary to run properly? I simply can’t find any of those jets anywhere, but i’ve heard of people taking the adjustment screw and modifying it to function as a jet by cutting it off at the threads, drilling a similar sized hole as the original, and drilling a divot in the side facing the float bowl.
Also, the owners manual says the compression pressure should be 120.89 psi (can someone confirm) and mine is reading right on 120. It’s very easy to kick over compared to similar bikes. It’s due for an engine rebuild and i’m 99.99% positive that the crankcase seals are bad due to it sitting for many years. But why does it have optimal compression pressure, but you can use one finger on the kick lever and turn it over?

Now that is an odd carb with two jets. I checked on line with CMSNL and they do show a jet below the regular pilot jet which is totally strange. Can you tell from the carb what it meters? so I took that number 09492-60003 and that came us as a Pilot jet, 0.7 which suggests that it might be an air jet.

https://www.partzilla.com/catalog/suzuk ... carburetor says it's unavailable

https://www.partzilla.com/product/suzuki/09492-60003

09242 are pilot jet numbers and 09493 are air jets and according to one list 60xxxx are #60 pilot jets and the last three digits indicate the jet shape/type/series but nowhere to be found is a 60003, but 09243-60003 shows up as a 0.6mm air jet. That makes me think that maybe the catalogs have the wrong part number.

If it's a simple air jet with one hole in the center and no cross holes, it is probably a B42/55 air jet and should be M6x1.00 thread and yes you could machine one out of something else.

120 PSI compression sounds fine for a street bike, but I'm surprised you can turn it over with one finger. A rebuilt GT750 is around 130 PSI. Is it a cheap ebay compression test gauge by any chance? They tend to be wildly inaccurate.

Thanks for the reply, I don’t understand what you mean by “Can you tell from the carb what it meters” I have already checked on that UK website that has the part diagrams with a incomplete selection of parts for sale, and as you said, it only says it is a jet. I would like to know if it is a necessity from someone who has tried to do it, being that they would be a nightmare to try to get. Also, the left carburetor has a second fuel inlet going straight into the intake that originally had a spring over the fuel line going to the diagonal facing inlet on the petcock. Is this also a necessity? They weren’t when I had aftermarket VM carbs on there. And the compression gauge is a Maddox kit and has proved itself worthy from a buddy of mine’s experience.

The T350 has an automatic vacuum-operated petcock. It’s controlled by the second line from the left carb.
It’s common for the vacuum mechanism on old petcocks to have problems. Switching to a manual petcock is a popular fix, you just need to put a cap on the carb’s vacuum port.
Another option is to a manual conversion to the petcock.

The T350 has two pilot jets in series. Not sure why, but the bike doesn’t run correctly if you don’t have the second tiny pilot jet that is unobtainable.
The tiny pilot jet looks different than the two Mikuni air jets listed on jetsrus.com.

An eBay seller has made new tiny pilot jets. Don’t know how well they will work because they are not exactly the same.
Lists having 5 available, so act fast if you are interested.
https://www.ebay.com/itm/164224359222

Looks like it just meters fuel and not air. That also explains why it's not listed in any Mikuni materials I have seen so far.

Why does it need one at all? I can only suggest that perhaps with a regular pilot jet, the motor pulled in too much fuel before it is mixed with air so they had to find a way to lean it out at idle. I wonder if that was a surging issue they tried to fix. You could try running the bike without that jet and see what happens.

If those jets that JABCB found are still available I'd suggest grabbing a pair. If the thread in the carb body is stripped that won't help much and you could try making a jet out of the screw you mentioned in the first post if it runs like crap without that jet.

Back in the 1960s when Suzuki first developed these bikes, the T20/T250 had 24mm carbs, the T305/T350 had 32 mm carbs, and the T500 had 32 or 34 mm carbs.
Suzuki didn’t quite figure out how to get those big T305/T350 carbs to work correctly on the pilot circuit. So they added those tiny pilot jets.

Over the years I’ve had 3 T350s. One didn’t have the tiny pilot jets. On the highway it ran fine but putting around in my neighborhood it ran like crap.
It ran fine when I installed those jets & made no other changes.

The threads are not damaged at all in the carb at all, and I have contacted the ebay seller and he will make 2 more for me since there’s only 1 left. Boy am I lucky!
Does anyone have any knowledge on why the engine has good compression but is so easy to kick over? No one has replied about that yet so i’m asking again in case others skipped over that in the original post.

My 350 has always been easy to kick over simply because of the Japanese standard compression ratio of 6.9 to 1.

Hmm. I’ve seen a few sites that have different compression ratios listed for T350s. I’m not sure which is correct, I’ve seen one say 8.5:1, other one said 6.9:1, another one said 6.7:1. I believe the owners manual for it says 6.9:1. It’s very likely the method for calculating the compression ratio they used long ago were inaccurate and the other specs posted may have been tested using modern tech to calculate it. Who knows?

So, i’m still curious as to why it’s so easy to kick over even though it has good compression. My dad told me back in the 80’s it had 125 PSI of compression and kicking it over if it was being stubborn would wear him out pretty quickly… If it was difficult for him then, it definitely would be for me too, but it isn’t at all at the moment.

I’d say it sitting since 1991 (maybe longer) would definitely cause some issues. Sat in the dry but was still exposed to the outside temperatures. Of course varying temperatures will cause seals to expand and shrink, eventually developing a leak somewhere. I have a gasket kit I’ll use very soon. I’m positive it won’t make it any harder to kick over, but it definitely needs it. My guess for the cause would be the crankcase to cylinder gaskets? If it doesn’t improve after I rebuild it I will for sure post about it. I’m not worried about that since it starts first kick with choke 95% of the time, just wondering what would cause it.

Anyway, thank you all for the replies, I’ve learned a lot. I definitely have a 2 wheeler addiction now minus the money to feed my addiction Lol.

Corrected 2 stroke compression is measured from closure of the exhaust port on the compression stroke. NOT as a 4 stroke from bottom dead centre (BDC). Different year models can have different compression ratios for lots of reasons, such as different port heights, different head shapes (squish or not) and if the head (or cylinder base) is skimmed as technology and engine performance requirements change. GT, TS, RD, TZ and other designated engine types are very different in power characteristics.
Primary compression (in the crankcases) also makes a difference as does disc valve, reed valve or combinations of those inlets dictate.. That's why 2 strokes have 'lower' compression ratios than other types of engine, but remember that a 2 stroke engine fires EVERY time the piston gets to TDC, rather than a 4 stroke that fires every second time it gets to TDC.
Thought all this engine tech was straightforward? Welcome to our world!!!!!

Gotcha. I’ve searched a lot of websites trying to figure out the “correct” compression ratio for it. Some says 6.7:1, a service manual says 6.94:1, and i’ve seen another manual say 8.5:1. I can’t find the proper compression ratio