PLease Help GS850 Carb Problems

[Anonymous]

Hey folks great site. I need some ideas. I picked up an 82 GS850 that had been sitting for about 10 years. I pulled the carbs cleaned them (didn't separate) I feel pretty good that they are cleaned thoroughly. I installed a new uni filter in the air box, new intakes, new plugs, oil and filter. The Problem is I cant get the bike to quit bogging under load past maybe 1/4 to 3/8 throttle. in Neutral no problems, the bike revs like a beast clean and quick. I have synced the carbs, adjusted float level from way to low to way to high in 1mm increments. Currently I have the float level at a point that fuel at times just seems to seep from the air cleaner side of the carb. I know I need to buy a book to get some needed specs ( float level, plug gap.....) but just haven't done it yet. It seems that the bike is needing more fuel in the mid range because while raising the fuel level the bike began to rev better to a point under load. I used the jets supplied with the K&L kit and my next swap hopefully this week is to change out the needle jets with the original ones. Diapraghms looked good and I played with the needle height a bit also . I didn't see any difference with raising the needle so I put it back to normal. I appologize for my long winded list of scatter brained tinkers so far but I think that I have pushed myself into a box where I just can't see the obvious so I sure would appreciate any thoughts any one might have. Thanks in advance and keep up the great work.
-Steve

[Anonymous]

Make sure the mains supplied are the stock mains for your engine, doesn't mean they are just because they listed that kit for it. Did you remove the rubber plugs beside the mains, then remove the pilot jets and clean them and the tunnel they screw into? Put the rubber plugs back in? The needle jets that your mains are screwed into have to be stock and clean also. Believe they just push out if the mains are removed. There is a place on this site that shows carb rebuild with pictures. If you have a fitting that fits into the bottom of your carbs (bowl drain) you can get the float height pretty good. Usually a carb sync kit will have a fitting that fits (with transparent tubeing). You really need a manual, some bikes are carb modified and others have carbs from a similiar bike swapped in. Ten years is a long time, did you remove the mixture screws and clean those areas? (under the plugs on the front of the carbs, have an o-ring and little washer in there with them). But they sometimes are really hard to remove.
Not really sure what RPM your at. Believe the pilot jet takes you up to around 3000 but the mains start kicking in before the pilots end. The size of the stock mains, pilot jets, air jets, might be in bikebandit.com microfishe if you can read it. Part numbers aren't Suzuki anymore but I think the size of the jets are there. It doesn't do much good to fool around with jets if the floats are high enough to leak, you are flooding.

[Anonymous]

Midnight Rider,
Thanks for the reply. I will check bike bandit tonight. Meanwhile I will update saying I backed the floats off a mil tonight and cleaned and put the stock mains back in I checked and the new ones matched the old ones at 115 but I stuck a push pin in and it would go all the way through the old mains but not the new ones. Poor production control I assume. I am going to take off Friday so I can get the title transfered and get the bike on the road to really find out what is going on. After testing it in the ally tonight it seems to be a lot better. When I hold the throttle wide open in first gear the bike really bogs to about 3000- 3500 then damn near flies out from under me as it picks up power, still seems to stumble though. Applying slow 0-maybe 3/8 throttle the bike will go through the gears great I will dig deeper and order a manual this weekend. BTW is clymers my best bet or is there a better manual out there? I did make sure all pasages were good and clean and installed new pilot with washer spring and o-ring. Thanks again and I will keep updated on the progress.
-Steve

[Anonymous]

I think 115 main jets are stock for my 16 valve 750e, so that's probably right or close. Someone probably drilled out the old jets that were in the bike. I would trust the new ones to be what they are stamped, before I would trust the old ones stamp. Sounds contradictory to what I said before but it's not. Rebuild kits are sometimes for the high performance 16 valve or a bike with the same CC's but lower performance so they come with two sets of mains, or just the ones for one of those bikes. Sometimes you might just get a packer that was thinking about something else. I know that never happens to me while I'm at work, but it could. It's too bad you can't get a factory service manual, there is a link on this site that sells copies or something but would be more expensive than Clymers. I can't stand Clymers but there are people who like them. I've seen in Clymers a half of a paragraph to explain something, where the factory service manual will use two pages, and another two pages to explain two ways of adjusting properly. It's like ordering from JC Whitney, you might get lucky on one specific part but if you didn't want your bike to work properly, why not just push it over a bank? 8O
By the way, make sure gas doesn't come out of the fuel tank petcock unless it's in prime. The float valves aren't built to have constant pressure on them. Gas should only flow when the engine is running, with the vacuum controlled petcock. So if you ever run out of gas with the petcock in the on position, and you're stopped, put it in prime for a minute and save yourself some trouble. ( before you move it to reserve
). If you're moving put it on reserve, you might think you have no reserve by the time the thing takes off.
At 3000 rpm you are moving into the mains. Your vacuum diaphrams, needle jets, needles, and main jets are all becoming very important. There are some guys on here that are real experts, like Keith. If you get the basics out of the way he might show up and tell you how to fine tune. If you were leaking fuel into the air filters, your plugs are fouled. You will probably have to replace them or clean them up. Also, really light coat of oil on that air filter, run without it once and see if that fixes your bog, or put the stock paper one back in for a run. If you got a heavy coat of oil on that filter it will do exactly what you are saying.

[Anonymous]

Midnight Rider,
I finally got it WOO HOO! I took tne new mains to work and ran some pin gauges through them and in fact they were all ove the map spec wise actually ranged from 113 to 115, I found a site that had a rule of thumb spec for mains and pilots that suggested about 6.5 mil over stock froo a 4-1 exhaust and foam filter so I lapped the new mains to 122 put hem in last night and the bike runs like a champ now. So while gettin the title transfer today I am going to stop by the bike shop and pick up some new 122 mains. should be ready to drive by tomorrow. Thanks for the suggestions I really appreciate it. Keep up the great work. OH yeah by the way I had dropped the floats back down 2mil from my original leaky height. Thanks again.
-Steve

[Anonymous]

Thats great! You'll find GSs that people gave up on just because they weren't properly jetted, very sad.

[Detman101]

Ah ha! so were those 122 mains mikuni or Dynojet?
Cause I've got some 122.5 mikuni mains as well.

My real problem is the idle range. over rich on 1&2 and slightly lean on 3&4 but all screws at 1.25 turns out. Is it common for the carbs to be set differently? What did you put your mixture screws at on each carb?

Dm of mD

[Anonymous]

jets were mikunis

Detman,
I started at 2.5 turns out and got the bike running then i kept dialing the adjustments in for the highest idle. Once i got that I lowered the idle to just above 1000 then tweaked them some more again repaeating the highest idle i managed to get them all within approx 1/4 turn either direction. Bike starts cold with the choke excellent maybe within 2-4 revolutions. When warm bike pops over in first 1-3 revolutions. As far as the mains the bike had mikuni jets in it when I got it. The ones i ended up lapping to .049 were K&L supplied jets. I found a web site that gave a great rule of thumb for upsizing your mains I will post address when I find it again. Hope this helps a bit.
-Steve

[Detman101]

Re: jets were mikunis

Detman,
I started at 2.5 turns out and got the bike running then i kept dialing the adjustments in for the highest idle. Once i got that I lowered the idle to just above 1000 then tweaked them some more again repaeating the highest idle i managed to get them all within approx 1/4 turn either direction. Bike starts cold with the choke excellent maybe within 2-4 revolutions. When warm bike pops over in first 1-3 revolutions. As far as the mains the bike had mikuni jets in it when I got it. The ones i ended up lapping to .049 were K&L supplied jets. I found a web site that gave a great rule of thumb for upsizing your mains I will post address when I find it again. Hope this helps a bit.
-Steve

Man, I tried that but the bike fouls out the plugs and stops running before I can even frickin adjust those damnable mixture screws. Maybe I'll start at 1 turn out and make it lean then go up from there since the way you posted didn't work for me.

I'm so screwed.


Dm of mD

[Anonymous]

That sounds foul

Detman,
I am not sure of your carburetor history, but have you checked all the basics like:
leaky petcock diaphragm, float height, carburetor sync, slide movement, main jet size. If the petcock diaphragm has a hole your engine vacuum will pull raw fuel from the tank making the mixture rich. If your float height is high then you will be seeping excessive fuel up past the needle, same goes for the main jet size. Also if your slide is hanging high due to binding, then more fuel will seep out past the needle. Hope this give you some direction. Post back with some background and history if you cant get it.
Good luck,
Steve

[Detman101]

Petey, what I did to fix my carb problem was this.

I took the stock floats out of a spare set of BS34SS carbs that I have and put them in the carbs I modified. Now the float levels are correct and not all wacky like when I tried to set them myself. I can ride the bike for more than 13 miles without emptying the carb bowls. In fact, just yesterday I went from Virginia to Baltimore without any fuel starvation issues besides actually physically running the main tank dry. The bike still runs rich but the solution to that problem is coming up in the next paragraph.

I then called MAC, the makers of my 4-into-1 exhaust to find out if it is really a high performance exhaust and to see how it compared to other exhausts. I found out that it only flows as much as a stock exhaust!!!

Well, that was the one missing part of the puzzle as to why I am running so rich! The bike is taking in more air, using more fuel, but trying to push it all out the same small hole that it had before.

So the answer to my problem was scaling the size of my main jets back from Dynojet 132 to Mikuni 122.5 mains.

The only instance that I could use the 132 mains in the bike would be if I took off the stock can and put a larger, better flowing muffler canister onto the header. I considered doing this as well but I'd really rather ride the bike and not play with it anymore. I have the plans made for when I am ready to make that move. But for now I'm sticking with a known constant that I know will work good. I know this because when the shop set up my bike for the pods and stocke exhaust these 122.5 mains were installed in the carbs. They were the only change that the shop made before I chopped off the stock exhaust cans and started experimenting.

So, in conclusion, I will be putting my 122.5 Mikuni mains back in the carbs this lunchbreak and will see how the bike runs. I know I'll have to reset my mixture screws but that is cake compared to the hell I've been through.

So by tomorrow I will be riding once again.

If I can help in any way please PM me. I'm glad to hear that your bike is running better now.

Dm of mD

[first timer]

hey detman call up mac they have 1.5" competion baffels for sale and 2" baffels. if i was you i would order a 2" comp baffel. you just pull out the old baffel in megphone and put in the new one. i am running a 1.5" baffel on my 550.
this was the site that was selling them but they have changed the site some so you may have to call and ask.

http://www.mcdistributing.com/

-ryan

[Detman101]

Awesome dude. Thanks for the link.

NOTE: My previous post about swapping the 122.5 mikuni mains in....well, IT WORKED!!! I'M RIDING AGAIN!!!

No popping, no hesitation, no heavy gassy smell in the exhaust.
And best of all, my gas mileage is back good. Took the ratbike for a ride around the beltway and didn't even get below a 1/4 of a tank!!!

WOOHOO!!! Next weekend, VA here I come!! (hopefully)


Dm of mD

[snowbeard]

right on Detman!!! I'm glad to hear both of y'alls bikes are working, but I've been listening to the horror stories outta dm for way too long!!! congrats!!

[Detman101]

Thank you hehe.
Most of those horror stories are the result of my own tinkering fetish.
I always mess around with it and muck it up. Luckily, with the help of Earl, Ryan and others here I got it back in line and running right again.

Now I'm leaving it alone and riding!


Dm of mD