Airbox question

[Guest]

Finally getting around to cleaning and rebuilding the carbs for realz this time. I have 2 questions I'd like to ask before sticking everything back together as 650 carbs are a pain to take out and reinstall. As far as I know these were existing conditions from back when the bike was running "good" last year.
1:On my airbox filter cover there is a hole in the dead center, I had stuck a radiator plug screw I had in the hole because I was scared of an air leak. Is this hole supposed to be there? Or is it a good idea to plug it?
2: on the intake splitter it has a port on the top and bottom. Obviously the top is for the engine breather hose. The bottom appears to not have anything to connect to. Should this be plugged off or is it supposed to be a drain of sorts? It seems to be a weird spot for a drain since it would spill out in front of the rear wheel.
I will post pictures as soon as I figure out how to with my phone

[jcskokos]

1535507684506355198915749915419.jpg
Side view of the splitter

[jcskokos]

15355078249331448329176189855614.jpg
Airbox and the makeshift plug

[tom203]

Question1: plug that hole in filter cover

Question2: the lower "drain" hole has a special hose with inline fitting - likely a ball in a plastic cage. When engine runs, the ball gets sucked up in cage to seal off this connection. When engine stops, the ball drops and any accumulated liquid (water,gas,etc) can drop thru this fitting to ground. Personally, I'd just block it off. But you can stillbuy it p/n #6

https://www.partsoutlaw.com/oemparts/a/suz/50d3fd96f8700230d8b4da73/air-cleaner

[fbody_mike]

Yup, later on Suzuki just used a tube with a plug in it for drain hose. During servicing you were suppose to remove the plug and drain out any water that had collected in the air box. You just do not want it open since that will let in unfiltered air. If it were me it would get a tube with a bolt stuck in the end, that tube usually runs down the back of the motor near the center stand.

[jcskokos]

cool, so Ill plug them both for now. The bike had both open when I first got it. I plugged the airbox cover when I got it running good then rode it for almost 7 years with the lower port open. I always had an issue with a hanging idle or a super high idle after freeway riding. I hope this was the cause. Everything else is in spec as far as I can tell. Maybe need to clean and oil the filter and shes back on the road.

[jcskokos]

Got everything back together. Starts right up and idles nicely. It will intermittently bog down when I try to accelerate though. Is this something that could be just needing the mix screws adjusted?

[jcskokos]

Ok. I'm pretty sure i have either a cracked intake boot or o-ring for #3. I'm getting tired of pulling these carbs.... lol

[fbody_mike]

But you will get really good at it

But an air leak will do it. If there wasn't a leak I would suggest raising the needle a little after a carb sync.

[jcskokos]

It's a cracked boot. 6 o'clock position. Now to decide if I should just replace the one or drop some money into all 4.

[fixmybrokecomputer]

If one has failed, the others aren't far behind. Now is when we find out just how tired you are of pulling carbs.

[jcskokos]

2 weeks later and all the parts are here and installed. No more hanging idle but has a nasty lag/big down just off idle. I have the idle hovering around 1200 rpm and when on the center stand it will audibly bog down and wont even go while in gear. Once above 2000 it will race away in neutral no problem. Air screws are about 1.5 turns out.

[Big T]

Air screws should be 2-3 turn out. Go to 2 1/2 and see if that bog disappears

[jcskokos]

Ok. Put it to 2.5 turns and still had a slight cut out unloaded so went 3 turns on all carbs. Now runs great unloaded but still wants to stall as soon as I let the clutch out. I've been trying the "highest idle" method but I can't really notice a change when adjusting the screws. I seem to remember a guide posted for the carb tuning but can't find it now. Then again that was at least 5 or 6 years ago since I used it.

[fbody_mike]

Try raising the main jet needle by shimming it with washers or on some carbs you flip the spacer around the clip. Either way raising the needle will ritchen the mid range mixture, I've found many times this will help with off idle bog.