Choke not Chokin'

[Scudder]

I have a 1980 gs850gl. When I choke it all the way it won't rev past 1500 rpms. It will climb a bit higher as it warms, but it seems like something is wrong. It runs fine, but as I ride I have to adjust the idle a couple times during the ride.

My gs750 will get up to over 3000 rpm with the choke full and I quickly have to reduce the choke because it revs so high. I'm thinking this is normal and the 850 is abnormal.

My question is this... Is this low choke rpms characteristic of the gs850s or is it something that I have to look into? At first I thought a stretched cable, but when I manually push the choke over, it doesn't increase the rpm. Maybe I need to remove the carbs an clean the choke better.

thanks
Scudder

[DanTheMan]

It's not truly a "choke" first of all. It's a fuel enrichener circuit. As the engine warms up, more fuel is atomized, causing the idle to increase. Have you done a complete carb cleaning, repalcing the old o-rings, etc.? Are the carbs bench synced properly? If they aren't properly bench synced, the rpm won't increase due to lack of air flow through the carb throats. There are a lot of places to look at, how's the air filter?
Look at BassCliff's carb tutorials, you'll find the problem there. Oh, one other thing, my choke cable is stretched and I have to clothespin it open to full choke. Could be your problem too.

[spyug]

Definitely not correct. I'm betting your "enricher" circuit is somewahat gummed up. Sounds like a clean and rebuild would be in order.

Don't feel bad if you've recently cleaned them as I've experienced a couple of occasions where it took more than one soaking to get things properly clean. I do hope you are dipping them in carb cleaner when you do it, however, as squirting with aerosol carb clean is not going to do it.

With a properly clean and functioning enricher circuit you should easily get her to rev better than 5gs. My 750 has on occasion ( when I forgot about it and it warmed up) gotten close to the redline...........oops.

Dunk 'em again is my vote.

Cheers,
Spyug

[Scudder]

I replaced the foam on the filter. I oiled it. Could I have oiled it too much, thus causing a lack of air flow? The rest of the things you mentioned, I have done.

Scudder

[Scudder]

I was thinking that I needed to dip them. I sprayed them the first and second go around.

Scudder

[DanTheMan]

I replaced the foam on the filter. I oiled it. Could I have oiled it too much, thus causing a lack of air flow? The rest of the things you mentioned, I have done.

Scudder

Over oiling will have a dramatic effect on the way it runs overall. WOT won't work well either. But, I agree with spyug. Remove 'em, tear them all the way down, replace all the o-rings, dunk em, clean all the passages with wire, blow 'em out real well, bench sync, and then see how it works.

[Scudder]

Gonna check the oil on the filter first. Then tear'em down, once again.

Scudder

[hampshirehog]

Crap in the float bowl were the enricher tube slots in. Give that hole a squirt of something to clean it out.

[Missile99]

Mine has been hitting a 4k rpm wall and sooty plugs too. Everything has been cleaned or replaced (entirety of carbs/fuel/ignition system including wiring and relay) so I was running out of options until tonight when I pulled the filter back a bit and took a test run. This was the first time that the choke actually increased the rpm of the cold bike as she warmed. The plugs finally showed some evidence of burning clean. Wow. I will check the oil on my filter tomorrow. It came from Suzuki pre-oiled and I don't think I tried to squeeze out any excess. I hope I'm on the right track and the same for you. I thought that the bike was suffocating more than not getting a quality spark. Anyway, a nice blue/white spark provided by Dyna-S and Dyna green coils is nice!!

By the way, thanks to all who dedicate their time here to answering questions and providing such wonderful information. I have been reading and reading on the forums over the past few months and am so very amazed. It really is fun to follow a thread and learn from all of you.

[Scudder]

Thanks. I hope it is the oil on my filter. I'm going to give it a shot when I get a chance. One thing that I've learned is that sometimes it's a little thing/easiest fix that can make a huge difference. I'm not as experienced in gs maintanance as most on this site, so I learn something new nearly everytime I come on this forum and then go to my garage.

Scudder

[tkent02]

There are three parts to the "choke" circuit, the air passage from the back of the carb, if this is plugged you will get more fuel but no more air as the choke is pulled on. Next the fuel system including the passage between the main float bowl area and the well for the fuel pickup tube in the float bowl itself, and the pickup tube with it's tiny ports. If any of this is blocked the choke will give you more air but not more fuel. And last the plunger mechanism and it's associated ports and passageways... Where all the mixing happens.

Just a guess, but maybe your air passages in one or more carbs are somewhat blocked, so you are getting more fuel but no more air when the choke is on? It seems like this would keep it from revving up normally, like you are describing.

Tiny bugs, or pieces of anything can clog this air passage up if the carburetor has been left open with no filter.
This combined with poor synchronization could be the culprit.

[mrbill5491]

I take it your bike has the CV carbs no? From my understanding once you start riding have the choke pulled out some that circuit is overriden by the opening of the throttle, so doesn't make alot of sense to have the choke or enrichment pulled out any.

[Scudder]

Could be any one of the things you all mentioned. When I got the bike the carbs were in a bucket with some other parts. The bowls were so bad they has black deposits in them. The main jets just twisted off when I tried to remove them. Rebuilt and cleaned the carbs. Didn't dip them. Started up fine and runs fine, but there are still a few lingering things that need to be shored up, like the choke issue, and an oil leak from the clutch shaft. I'll get to the bottom of it all eventually before it's riding weather again in Chicagoland. Getting 6 inches of snow today, so I've got time.

Scudder