33 smoothbores/bogging

[tbax]

Just purchased a 1980 gs 1100e that came with 33 smoothbores. The bike runs good wide open but you have to nail it above 4000 rpms in 1st. Any lower and the bike will absoultly kill itself. In the other gears you can't even give it half throttle without it bogging unless you feather it ever so easily. I cleaned the carbs throughly and it has 125 mains 3rd clip and 1/2 turn out on the air screw. For the life of me I can't remember the pilots which is probably where my problem is but any other help is appreciated greatly. Other than carbs and 4 into 1 the engine is stock. Thanks.

[rapidray]

Are the carbs CLEAN & CORRECT float heights? Start there to eliminate variables. Ray.

[tbax]

Yes the carbs are clean and the fuel level is about a 1/2 inch below the bowl gasket.

[rapidray]

I would look at reducing the pilot jet size with these symptoms. Are you sure there are NO vacuum leaks anywhere? If no leaks I would start with a smaller pilot & lowering the needles 1 clip position. Just a start. Ray.

[Nicholaschase29]

you have to roll onto the throttle with those carbs you cannot just whack the throttle open at low rpm. At lower rpms if you whack the throttle open the air velocity is not moving fast enough through the carbs to lift the correct amount of fuel though the carbs to your engine.

[tbax]

Even a slow roll on will cause it to bog out. I'm talking about 2 seconds from say a quarter to full throttle. The intakes are sealed with new boots but I did notice that there are three nipples for hose on the carbs. Two I know are for venting and the odd one facing the other way I do not know what is for. I did try plugging and unplugging it but it ran the same way both times. Where else could I have vacume leaks? Help is greatly appreciated. I will also look to see what pilot jets I have. Does anybody have a good place to start as far as jets and etc. for this bike/carb combo?

[SqDancerLynn1]

what type of air filter do you have ?

[tbax]

K and N pods.

[rapidray]

The "odd" one facing the other way is a vacuum opening. You can plug it or use it to operate the stock petcock. Do NOT leave it unplugged! Unlike what Nicholas believes, when the jetting is spot on you CAN slam the throttle wide open & it will respond correctly. Ray.

[tbax]

I have been running with the nipple plugged just to make sure all vacume leaks are sealed. I believe a change in the pilot system and maybe a change to .6 on the airjets may help. But these ARE extremely picky carbs just as the myths say.

[KEITH KRAUSE]

I think too much fuel is in the mixture and it can't handle it until the rpm's pick up enough to help it clear itself.
From your description on how to minimize the bogging and how it must be throttled, it could be the pilot circuit, cut-away, jet needle position, or even the mains, or a combo of them. This assumes the bike is in otherwise good tune. Keep in mind that performance, regardless of the jetting, will be compromised because the vacuum tool synch must be done. You must at least bench synch the slides as carefully as you can but the bench synch is no substitute for a vacuum tool synch.
Careful attention to exact throttle position when testing might help narrow it down as to which circuit is causing the bogging. Overlapping between circuits that aren't jetted correctly can add confusion and be a PITA to figure out.
Mark your throttle grip and housing and find a quiet area to test. Forget about rpm's and focus on throttle position. Changing throttle position is OK but also try to hold a steady position at various points to see what happens and this may also help minimize overlapping between circuits. Pretend you only have 1/2 throttle to use. Don't go past it. If you still have bogging, that eliminates the main jet because the main simply doesn't regulate fuel until after 3/4 throttle.
Next, run the bike at 1/2 throttle even if it's hard to get there at first. Now back off to 1/4 throttle. Any problem? Holding that 1/4, now go back up to 1/2. Any problem? If not anything serious, that eliminated the jet needle as the cause of bogging since the jet needle regulates mixture within the range of those 2 positions. If it bogs between these positions, adjust the e-clip one position higher on the needles.
If you then test JUST under 1/4 throttle, you're mostly on the cut-away since the cut-away regulates mixture and provides the transition from pilot circuit to jet needle.
Even less throttle places you squarely in the pilot circuit.
I realize it's not easy to test on the street but if you had a Dyno, the performance at various throttle positions is what would be checked to see where your problem lies.
If you undertand the jetting circuit sequence, it may help you narrow it down. Various charts and info out there will differ a little as to when this or that circuit kicks in but the above is close enough to get you in the right direction.

[KEITH KRAUSE]

Also, there must be some info out there as to what size cut-away works best with the 33's and Suzuki's. Same for the air jet. Without knowing these 2 basics, it can be complicated.

[renobruce]

Also, there must be some info out there as to what size cut-away works best with the 33's and Suzuki's. Same for the air jet. Without knowing these 2 basics, it can be complicated.

Standard jetting for the Suzuki is 132.5 Main, 0.6 air jet, 17.5 pilot jet,
6DJ30-4 jet needle, #261 0.6 needle jet, 2.0 throttle valve, air screw 3/4 turn out.

[tbax]

Thanks for all of the replies. The information will be helpfull. Now time to go find my favorite test and tune site. Now where did I put my police scanner?????

[rapidray]

Standard jetting for the Suzuki is 132.5 Main, 0.6 air jet, 17.5 pilot jet,
6DJ30-4 jet needle, #261 0.6 needle jet, 2.0 throttle valve, air screw 3/4 turn out.

I'll tell you right now Bruce, a 132.5 main is TOO big for a piped & otherwise STOCK 1100 or 1150. My 1150, with a V&H street 4 into 1, only wants a 125 main WITHOUT filters on it. No, wait, that was in Tucson at 6800 ft. corrected altitude! Oh well, it still went 11.40s at 119! The 132.5s are probably pretty close for lower altitudes. Sorry about that one! Ray