82 gs650g odd behavior - need advice

[chaosmstr]

So I got my hands on a project bike.. it was given to me in pieces. Flat back tire (leaked at the bead), tore up seat, no carbs initially, then they were given to me in pieces, 2/3 of the switches were not functional.

The rest is fixed, but it's not running right.

I've disassembled and cleaned the carbs... replaced the o-rings, adjusted the floats,soaked everything in carb cleaner.
Adjusted the air mix screws to 1.5 turns back from fully seated.

It starts.. it runs.. but only on the two inner cylinders.

Adjusting the mix on either of the outer carbs does nothing. (mix screws work fine on the two inner). I can pull the wires on the two outer plugs and it still runs. I can pull the plugs completely out, and it starts right back up and idles (after it's been running for a couple mins and is warm, that is)

So I can start it, but it is a bear to start when cold, it idles, it revs up.. but has no power cause only half of the motor is working.

And when I do rev it up, it is slow to respond from idle and when I let off, it doesn't drop quickly.. it just kinda drifts slowly back down to idle.

I get spark on the two outer cyls, the two outer carbs are filling with fuel, all the jets have been cleaned...

What am I missing?

 

[Nessism]

For one thing the mixture screws should be set to 2.5 - 3 turns out for starters.

1 & 4 are on the same coil, so you could have a spark issue. Check spark to see where you are at with that.

Oh, and if you didn't see the carb rebuild tutorial linked in my signature please go though it. And check out the Top Newbie Mistakes thread too. Lots of good info there which may help.

Good luck

 

[chaosmstr]

I had found this XLS file.. http://members.shaw.ca/johnwightman/images/SuzCarb.xls
and that's where I got the 1.5 turns from.

I had found the carb rebuild guide and used it.. but didn't see the top 10 for newbies.
So, next is to check my spark again and measure my valves.
Hmm.. need some feeler gauges for that. Drat.

Thanx for the feedback..

 

[chaosmstr]

Well.. main issue resolved.
Running on all 4 now.. had knocked loose one of the wires to a coil.

Feelin dumb tonight! *laugh

Still need to check my valve clearance and play with my mix screws.. cause idle was all over the place.

 

[Erki]

haha I did that too, Cleaned my carbs put them back in and it ran worse. got ready to check the coils and noticed I bumped and unplugged one of the coils. ran much better once plugged in.

 

[BigD_83]

You've got a great bike there (check my sig...I'm biased)

1.5 turns out is the factory setting, and plenty of peeps on here start out at 2.5. Without checking my notes I think I ended up at close to 3 turns out.

Hanging idle when you let off on the throttle...sounds like an air leak, and I bet if you go through the carb rebuild tutorial you'll solve that problem, too. You must replace the intake o-rings if you haven't already. They WILL be flattened and hard. How are the airbox boots? Soft and pliable or hard and brittle?

In what kind of shape are the airbox and filter?

 

[chaosmstr]

I was given individual sponge air filters for the carbs.
They are currently dry, as I have not yet oiled them.

The main jets.. I have no idea if they are stock.. I think they have 4 holes on one axis, and 3 in the other.

So.. How do I figure out what the jets are.. and if I need to go back to the airbox? (something I'll have to buy, as the bike didn't come with it)

I didn't check the intake o-rings. *sigh

Take the carbs off AGAIN.. try #.. 6?
*sigh

 

[koolaid_kid]

Ummm, you might want to re-assess where your mains are. Main jets are in the fuel bowl and have one large hole through the central axis.

 

[chaosmstr]

My bad.. I was referring to the needle jet.

So, is it the main jet or the needle jet that needs to be replaced if you change your air filter types?

 

[Steve]

It is the MAIN jets that need to be changed.
Have not heard of anyone changing the needle jets after doing any mods.
Changing the jet needles can help, that's the best part of a DynoJet kit.
If you go to extremes with filters, header, cams and other stuff, you might need to bump the pilot fuel jet up one size, but on your bike, you shouldn't have to.

.

 

[chaosmstr]

Lovely..

Well, it runs. It starts up needing choke at ~60F.. and idles good after it warms up.
It has these Unifilter foam filters (currently dry) on the thing and it will not rev past 6k, even though I have the air screws at like 3-3.5 turns open.

So I assume I need to replace the main jets, or fine an original air box and filter.

Anyone know off hand what the stock main jet sizes are, and what I should change them to if I can't find an original airbox?

 

[TheCafeKid]

Lovely..

Well, it runs. It starts up needing choke at ~60F.. and idles good after it warms up.
It has these Unifilter foam filters (currently dry) on the thing and it will not rev past 6k, even though I have the air screws at like 3-3.5 turns open.

So I assume I need to replace the main jets, or fine an original air box and filter.

Anyone know off hand what the stock main jet sizes are, and what I should change them to if I can't find an original airbox?

Scour eBay and post a wanted in the parts wanted section here for an airbox.
Ditch the pods till you get it running right in stock form to decrease your headaches.
The main jets are only part of the problem. The stock needles are too fat to deal with the increased airflow pod filters provide. Thus a dynojet kit is needed for the specially designed needles. The jets are less of a factor, though they're included with the kit. Even if you change the main jets, the stock needles will not deliver enough fuel soon enough in the needle circuit, which is where you spend most of the time aside from cruising. The bike will fall on it's face as it does now.

So, find an airbox, get a new filter for it, seal it up tight, and continue working from there. Once you've worked the other problems out, and wish to change the intake and or exhaust system out, you'll find it easier to undertake knowing that you have a good base to work from.

 

[Steve]

Anyone know off hand what the stock main jet sizes are, and what I should change them to if I can't find an original airbox?

The stock MAIN jets are 110.
The stock Pilot FUEL jets are 42.5.
The stock Pilot AIR jets are 160.

What you need to chang them to would depend on what you have on the bike for air filter(s) and exhaust, but it's usually something like 2-4 sizes for exhaust and 3-5 sizes for intake. Those are MAIN jet increases. Usually don't have to change the pilot fuel jet until you install a big-bore kit and cams. You would still need the jet needles, they are only available with the DynoJet kits.

.

 

[chaosmstr]

I believe the exhaust is stock.. there are two 2-1 pipes. I think the only thing changed was the air intake system.

 

[Steve]

In that case, it would depend on how oiled (restrictive) your filters are.

You might need something in the way of 117.5 or 120 mains.

.

 

[chaosmstr]

Well, a stock airbox isn't going to do me any good.
The main jets are 122.5...

What a pain.
So, I either go back to stock or it's trial and error on the filters/jets.

Grr.

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. chaosmstr,

Much wisdom has been collected in the links below. Your bike is not really behaving oddly for a 30 year old machine that needs 20 years worth of maintenance. Be sure to click and read.

Let me dump a TON of information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed. I will put you on my prayer list.

Thank you for your indulgence,

BassCliff

 

[chaosmstr]

Good news and not so good news.
Runs great! I was being an idiot and trying to tune this thing with dry foam air filters.
Oiled the filters and adjusted the mix screws and runs like a top..

Not so good news?
Dropped my tank while working on the paint job.
Had it totally stripped down, bondo'd the dents, primer'd, $23 a rattle can of color changing paint.. was wet sanding that last coat before clear coating it, and it fell off the hook I was hanging it from.

*sigh*
But it runs right! I just need to put in alot more work on the tank....