Suzuki 2 Strokes

Got the exhausts back on this morning and fired the 550 back up. Much much quieter now tha all the ports have been chamfered. BUT the center still refuses to run.. I thought surely it was a seal, but it has plenty of vacuum. I didn't use the vacuum gauge, but it will suck your fingers in. Cracked the bowl drain screw and fuel ran out. The timing is spot on and there is spark at the plug. So WTF?
It's got fuel. It's got plenty of vacuum to pull the fuel. There is spark. The spark happens at the right time. So again WTF? What am I not seeing?. The outers run just fine and the bike fires up instantly, but only on two. The Float levels are exactly the same across the board. Yet the center won't run. This COULD be a perfect bike, but nooooooooo.

EDIT: The air screws are all at 1 1/2 per book. The fuel is fresh, ethanol free. It was definitely worth the effort involved to tear it down and chamfer all the ports. It made a huge difference in that respect. All the plugs are new B 8's.. I thought maybe I needed a hotter plug in that hole, but when I fired it up originally I was all new B 7's. Center didn't run then either.

OK. Here's what I have done so far. I took all three pods of so I had something to compare the vacuum to. The right and center pull better than the left, but the left is running without issue. While at idle, I sprayed starter fluid in the center carb.. Idle immediately jumped to over 3k till the fluid burned off. I did it twice and the center definitely picks up jumping to over 3k both times, AND the pope gets hot!
So, I think the only thing I can do is try increasing the float level in that carb. I'd rather take an ass whooping than pull those carbs AGAIN. Then if it's still not right -- AGAIN.
I did not try adjusting the air screw. Is it possible I could get there with just that? She sure came to life when that starter fluid hit. I am open to any and all suggestions and ideas.

So does it not run at any throttle position, or just idle?

I think you mentioned a fuel supply problem to that center carb. Did you fix that and do all 3 float bowls contain more or less the same amount of fuel?

I didn't find any obstruction of the fuel supply to the center carb. All the float heights are set the same so I can only assume the bowls have the same amount in each.
The top end is fresh and I'm trying not to run it over 3k. Center pipe eventually gets WARM, but I assume that's heat transfer because it's only warm. You can wrap your hand around it - no prob.. Besides that, the center should run at all RPM's. Has to run around 1000 when balancing the carbs. In reality, the cylinder should run all by itself. Currently this wouldn't do that on a dare.

I just changed the center air screw to 1. It seems to be running on all three, but I kept having to rev it to about 3k as it was tying to die at idle. The pipe did get hot, but that might be a fluke from keeping the R's up. I'll have to let it cool off and check again

Well, that does it. I changed the air screw setting to 3/4. I pulled the left and right plug wires and it started on the center all by itself. Runs smoothly at 1200 with the choke on. shutting the choke makes it die immediately. I can keep it running with the throttle, but backing off makes it die. Choke on, start again and it runs smoothly, again at 1200.. This should tell me something but I'm not sure what. Running with the choke on would indicate a clogged plot but believe me, it's not. I'm thinking my fuel levels are low and need to be changed by 1/16 or so. Thoughts? Remedies?
Sure put a smile on my face when she started all alone on the center.

It has to be some sort of restriction in the pilot jet circuit or an air leak. Did you check the outlet and bypass outlet holes on that carb compared to the other two? I have had that problem more than once.

When going through the carbs, with pilot jet removed I use 100 PSI in the hole the pilot jet screws in to. According to the book, the bypass intersects the pilot hole.. When I install the jet, I use an eye dropper and alcohol to watch how quickly it drains out the pilot hole. Is there another way to clean the bypass?
Looking at an old carb on the bench I see the pilot hole goes straight through and the bypass hole is at an angle. It is possible that angled hole is blocked. Any idea what size that bypass hole is?. It's really tiny but it seems like wire is the only way to clear it. If I fill the jet hole with alcohol and hold mi finger over the main outlet hole, the fluid should run out the bypass hole. Correct?

However. Before I do all that, I'm going to order new intake boots. The center boot is visibly split where the clamp goes around it on the motor side. I don't think it goes all the way across the clamp surface but I suppose it's possible there is an air leak there. The boots are old and hard anyway so I might as well take them out of the equation. There goes another week or more
Honestly though, even if there was a tiny air leak, I doubt any air would be drawn through it when the carbs are wide open like this.

Ganged carburetors. What a lousy idea. I have to take EVERYTHING apart the get to the center carb

Chris,

Both outlet holes are very small so the way I test them is to grab a can of carb cleaned and spray it through one carb at a time and compare the flow pattern/strength. It is not uncommon to have one outlet flow way less that the others,

The carbs ore off. Visually, the bypass appears to be open. I can still remove the bowls and perform the test without separating the 3. Do you do the test with the jet in or out?

I normally do it with jets out and test the jets the same way, but testing with jets in might be a good way to see how they flow as a system and pull the jet only of there's a large difference.

carbs synced? Maybe that one the slide is setting lower than the others

Carbs were bench synced with a .031 wire. Actually I used .031 wire as a 'GO' gauge and a .040 as a 'NO GO'. Naturally I can't balance them till it is running half assed correct..
What baffles me is the vacuum on that center carb is very strong. why then is it not sucking fuel. Oddly enough, that cylinder WILL run by closing the air screw to 3/4. The other 2 are set at 1 1/2 per book and work fine. It's not normal for one off so far, or is it??
Personally I think all that is wrong is my float levels are a little low, but I'm no expert. Besides, the float levels are the same all the way across. 2 pull fuel, 1 doesn't - unless I cut off half the air