any oldtimer carb tuners here?

[AJAY]

I bought a 1982 Suzuki GS1100e over the summer. Not running, thought it would be just carbs and tires, but it's been taking more work than that.

The bike has a Kerker, individual K&N pod filters, and a Dynojet stage 3 kit installed. I've had the carbs off 4 times now, and the last time I completely disassembled the rack and dipped everything, and replaced all seals.

It starts easily and mostly runs pretty well, but has a bad stumble from 3 to 4,500 rpm. This should be where it transitions from the pilot jets to the main jets. Below 3000 she's smooth, and above 5000 to redline she's very strong, but the stumble is annoying.

The needle is currently raised one clip from the mid position recommended in the Dynojet instructions. The needles were raised two rings when I got the bike, so I compromised between his settings and the Dynojet directions. I'm not sure he ever had it running well anyway, given that he gave me a big box of jets and a set of plugs for one heat range higher.

I'm thinking that at 3-4000 rpm, the slides start raising and the mixture is either too rich (needle too high) or too lean (needle too low). Wish I had some way to measure the air/fuel ratio while riding it.

Anybody have any ideas?

 

[lonner]

most old school suzukis dont like pod filters for this reason and why most retain the oe airbox.

try this site as top guys for this type of thing .

hopefully site will be ok when you see this

OldSkool Suzuki .infoBoard - Maintenance Mode

 

[AJAY]

Thanks, Lonner. Wish I had the original airbox. Heck, I wish it had the original pipes and jets too! Even with the go-fast parts, it's still no Hayabusa. The OldSkool Suzuki board is down. I've also been on theGSResources.com website, but thought I'd try over here.

 

[karnage]

Those kerkers sound bad ass.I remember when my brother had one on his GS750.Could be an ignition issue.Have you synced the carbs??I used to be good at tweaking carbs.

 

[09GraySilverBusa]

Take it for a short run without the air filters to see if it gets worse or better at that RPM transition.

 

[AJAY]

Take it for a short run without the air filters to see if it gets worse or better at that RPM transition.

That's a good idea. If it's too rich, it should get better, too lean it should get worse.

 

[09GraySilverBusa]

That's a good idea. If it's too rich, it should get better, too lean it should get worse.

Yep

 

[smac]

What size are the carbs? 29mm or 33mm? If you have the 33mm carbs they are too big for stock bore (I had the same problem using the k&n filters). I tried all kinds of configurations, changed pilot jets, main jets and needle jets. Also ran the needle adjustments up and down. Stock bore just would not pull enough volume of air through the carbs at certain rpms. Fixed the problem with a big bore kit! Also replace your clutch basket that was a week link in those bikes..

 

[AJAY]

What size are the carbs? 29mm or 33mm? If you have the 33mm carbs they are too big for stock bore (I had the same problem using the k&n filters). I tried all kinds of configurations, changed pilot jets, main jets and needle jets. Also ran the needle adjustments up and down. Stock bore just would not pull enough volume of air through the carbs at certain rpms. Fixed the problem with a big bore kit! Also replace your clutch basket that was a week link in those bikes..

Stock 34mm Mikuni BS34SS carbs.

How'd you know I had clutch problems too?! LOL!

 

[GIXERHP]

Where do you have the air fuel screws set at??

 

[AJAY]

Where do you have the air fuel screws set at??

Base setting for the mixture screws is 2.5 turns out. I currently have them at about 3 turns out. Pilot jets are stock size. I doubt mixture screws would have much to do with it at this high an RPM with the butterfly open. What were you thinking?

 

[GIXERHP]

Who's jet kit, is it,, any idea?

As for the fuel screws, i would go to 2.5 turns, and see if the problem changes any!

Also the brass tubes that the needles go into, are they in good condition,
make sure they are not oval where the needle go in and out of!

 

[VIPER]

you need to hook the carbs up to get em synced. Are the headers getting discolored? Do they glow red when hot? If so you are running to rich. Your really nee to sync them though. Watch which headers are dicoloring or running hottest. this will give ya an idea as to were your problem lies. And yes redo the clutch. It was common for guys to use regular motor oil in those old scooters. Bad on the clutch plates etc. They will stick a lot.

 

[smac]

If you have the stock cv carbs, I would start by putting the stock air box back in your bike. That should take care of the majority of your problems.