Someone please check my homework - no idle without choke

[sultan]

'83 GS650, 22K miles.

This is probably going to be about 3 posts in one. My apologies. For those that can stay with me, I appreciate the feedback.

Had problems in the fall with starting while it was cold out. Forums suggested adjusting the valves. This spring, a plan to pull the oil pan to fix a leaking plug turned into rebuilding half the engine. I have just completed:
-replaced the rings
-honed the cylinders
-lapped the valves
-adjusted the valve clearance
-replaced all gaskets
-spark plug caps are new
-spark plugs are newish (<500 miles, replaced in fall)

Last night went to start it up, and to my amazement, it actually started! (This is the first time I've done anything like this with an engine. Thanks goes out to everyone that helped with replying to my previous posts!) However, after all this work, the thing still isn't running right. It won't idle, even after warmed up, without the choke on. More info:
-checked compression, got 175-180 psi dry in each cylinder with full throttle on. wet compression was insanely high, over 250. (Random question, why does the compression go up with full throttle? Initially I cranked the bike with no throtlle, and was getting 60-90. With full throttle, it always went right up to 180. I don't understand this.)
-the bike does respond to the throttle, and will rev up to 5,000+ rpm with no problem using the throttle.
-I attempted to adjust the idle screw (behind the carbs, below the airbox, facing rear) with no effect (side question: is IN higher/faster idle, or is OUT higher/faster?)
-just for kicks, I removed the air filter while the bike was running, and that had no effect whatsoever. Same with the cover on and I plug in the air inlet hole.
-the bike starts with the choke on and runs around 2000 rpm. as it warms up it gets faster and faster. i can keep turning the idle down to a point, but once it's warmed up, the choke still needs to be about 1/3 on in order for the bike to stay running.
-the PO *said* that he'd recently had the carbs worked on when I bought the bike last summer (yeah, right)
-I started the bike on a warm day over the winter *before* any engine work, and it was exhibiting symptoms similar to what it has now.

From doing research on the forums, it seems that this could be caused by any one (or combination) of four things (that I found, anyway):
1. clogged carbs
2. bad/clogged petcock
3. Bad gaskets/seals/rubber on the boots between the carbs and the engine
4. leaks from the airbox.

The seals on the fuel boots seem ok. The rubber isn't cracked, and I tried spraying WD40 on them while the bike was running, with no change. Given that the bike revs to high rpm ok, I'm going to guess it's not starved for gas, thus the petcock is probably ok(?). And, knowing my luck, between any 2 problems I'm going to have the harder one, so it's probably the carbs.

There seems to be some disagreement as to whether to just clean the parts and change the o-rings, or buy a whole rebuild kit:
http://www.thegsresources.com/_forum/showthread.php?t=125123
I guess I'm going to try the o-rings first, then order rebuild kits if anything seems to look suspicious. Does this sound reasonable?

Given that I know nothing about carbs (I knew nothing about rebuilding an engine a month ago) I'm sure I'll find the GS carb cleaning guide very helpful:
http://www.thegsresources.com/gs_carbrebuild.htm

I assume that after a rebuild/clean of the carbs, I'll need to synch them? (Again, don't understand how to do this yet, but I have the manual.) Should I get an actual manometer:
http://www.motionpro.com/motorcycle/tools/syncpro/
http://www.carbtune.com/
or just make one myself:
http://www.vfrdiscussion.com/forum/lofiversion/index.php/t16200.html ?
Is there anything that I can to do harm the bike by using a homemade manometer? How often (time/miles) do you really need to balance the carbs?

But before I get into this, am I on the right track? Is there anything that I could be missing that could be causing this? Anything else I should check or look at? Anything else this could be? Anything else I could to in order to narrow down the problem? Any other info you need in order to better advise me?

If I need to take the bike someplace, is it going to *hurt* anything to leave the choke on while riding it?

Thank you everyone for your advice. (Last side note: I showed one of my friends who's a scooter-head to a previous post on this forum. He said "Gee, your suzuki guys are friendly. When anyone posts a newbie question to the scoot forums, they often get flamed big-time." Just so you know...credit where due...)

 

[tkent02]

'83 GS650, 22K miles.

This is probably going to be about 3 posts in one. My apologies. For those that can stay with me, I appreciate the feedback.

Had problems in the fall with starting while it was cold out. Forums suggested adjusting the valves. This spring, a plan to pull the oil pan to fix a leaking plug turned into rebuilding half the engine. I have just completed:
-replaced the rings
-honed the cylinders
-lapped the valves
-adjusted the valve clearance
-replaced all gaskets
-spark plug caps are new
-spark plugs are newish (<500 miles, replaced in fall)

Last night went to start it up, and to my amazement, it actually started! (This is the first time I've done anything like this with an engine. Thanks goes out to everyone that helped with replying to my previous posts!) However, after all this work, the thing still isn't running right. It won't idle, even after warmed up, without the choke on. More info:
-checked compression, got 175-180 psi dry in each cylinder with full throttle on. wet compression was insanely high, over 250. (Random question, why does the compression go up with full throttle? Initially I cranked the bike with no throtlle, and was getting 60-90. With full throttle, it always went right up to 180. I don't understand this.)
-the bike does respond to the throttle, and will rev up to 5,000+ rpm with no problem using the throttle.
-I attempted to adjust the idle screw (behind the carbs, below the airbox, facing rear) with no effect (side question: is IN higher/faster idle, or is OUT higher/faster?)
-just for kicks, I removed the air filter while the bike was running, and that had no effect whatsoever. Same with the cover on and I plug in the air inlet hole.
-the bike starts with the choke on and runs around 2000 rpm. as it warms up it gets faster and faster. i can keep turning the idle down to a point, but once it's warmed up, the choke still needs to be about 1/3 on in order for the bike to stay running.
-the PO *said* that he'd recently had the carbs worked on when I bought the bike last summer (yeah, right)
-I started the bike on a warm day over the winter *before* any engine work, and it was exhibiting symptoms similar to what it has now.

From doing research on the forums, it seems that this could be caused by any one (or combination) of four things (that I found, anyway):
1. clogged carbs
2. bad/clogged petcock
3. Bad gaskets/seals/rubber on the boots between the carbs and the engine
4. leaks from the airbox.

The seals on the fuel boots seem ok. The rubber isn't cracked, and I tried spraying WD40 on them while the bike was running, with no change. Given that the bike revs to high rpm ok, I'm going to guess it's not starved for gas, thus the petcock is probably ok(?). And, knowing my luck, between any 2 problems I'm going to have the harder one, so it's probably the carbs.

There seems to be some disagreement as to whether to just clean the parts and change the o-rings, or buy a whole rebuild kit:
http://www.thegsresources.com/_forum/showthread.php?t=125123
I guess I'm going to try the o-rings first, then order rebuild kits if anything seems to look suspicious. Does this sound reasonable?

Given that I know nothing about carbs (I knew nothing about rebuilding an engine a month ago) I'm sure I'll find the GS carb cleaning guide very helpful:
http://www.thegsresources.com/gs_carbrebuild.htm

I assume that after a rebuild/clean of the carbs, I'll need to synch them? (Again, don't understand how to do this yet, but I have the manual.) Should I get an actual manometer:
http://www.motionpro.com/motorcycle/tools/syncpro/
http://www.carbtune.com/
or just make one myself:
http://www.vfrdiscussion.com/forum/lofiversion/index.php/t16200.html ?
Is there anything that I can to do harm the bike by using a homemade manometer? How often (time/miles) do you really need to balance the carbs?

But before I get into this, am I on the right track? Is there anything that I could be missing that could be causing this? Anything else I should check or look at? Anything else this could be? Anything else I could to in order to narrow down the problem? Any other info you need in order to better advise me?

If I need to take the bike someplace, is it going to *hurt* anything to leave the choke on while riding it?

Thank you everyone for your advice. (Last side note: I showed one of my friends who's a scooter-head to a previous post on this forum. He said "Gee, your suzuki guys are friendly. When anyone posts a newbie question to the scoot forums, they often get flamed big-time." Just so you know...credit where due...)

First of all, don't let it run much playing with the idle, if you can safely do so ride it, to get the rings seated. There is a short window of opportunity to get a good seal.

So it wasn't idling all that well before?
Carbs probably are plugged up in the pilot circuit, or they are completely adjusted incorrectly. For one reason or another the choke is supplying fuel when the pilot circuit can't.
There are tiny passages that need to flow fuel in order to idle, much smaller than what it uses to run under power.

Could be vacuum leak related, would have to be a pretty big leak.

 

[maro]

I'm sure someone with more knowledge of that specific problem will chime in and help you. I have an 81 650G. I did the carb clean this winter..I didn't have to order a kit. Just get the o-rings and you are set. Worry about the synch once you get those suckers back on. I had a fellow GSR'r in my area help me with my synch. Anyway, hollar at me if you have questions with your carb clean.......but maybe you'll get lucky and solve you choke issue otherwise.

good luck

 

[Dave8338]

WOT allows for full air intake as opposed to very little at closed throttle (CV carbs).

Sounds like you may have the o-rings between the boots and the head, giving you some trouble. Where does it idle at with choke on? When you get to half choke does it want to die out? If there is no adjustment when using the adjust knob (with choke on)...it suggest a lean condition.

Did you soak and replace all the o-rings in the carbs? Run a small wire through all the passages? Blow compressed air through everything?
New air filter? (oiled)? All clamps tight and carbs FULLY seated and tight?

Your compression is better than it needs to be, and them some!

 

[sultan]

WOT allows for full air intake as opposed to very little at closed throttle (CV carbs).

Sounds like you may have the o-rings between the boots and the head, giving you some trouble. Where does it idle at with choke on? When you get to half choke does it want to die out? If there is no adjustment when using the adjust knob (with choke on)...it suggest a lean condition.

Did you soak and replace all the o-rings in the carbs? Run a small wire through all the passages? Blow compressed air through everything?
New air filter? (oiled)? All clamps tight and carbs FULLY seated and tight?

Your compression is better than it needs to be, and them some!

I'm going to replace the o-rings between the boots and the head (Actually, I may already have these...I ordered a full "gasket kit" and have 8 pieces left that I couldn't figure out where they went...4 of them are black o-rings of about the right size. The others are small red o-rings of some sort. Or, should I just order ones that I'm *sure* are for this purpose so that they don't melt?) as a matter of course when I take off the carbs again.

I did *nothing* to the carbs while I had them off.
The air filter has been cleaned and oiled.
I did my best to make sure all clamps and everything around the carbs was properly seated and tight. I had one intake boot between the air box and carb #1 that was a huge hassle to get on. As I would tighten the clamp, it would just slide off the carb. I believe I have it on properly now with no leaks/gaps.

With full choke on after warmed up, it will 'idle' at well over 5,000 rpm. It would start out around 2,000, and after a minute or so start increasing, then keep going higher and higher until it sounds like WOT. With half-choke, it will idle somewhat lower while warm. With 1/3 choke, I can get it to idle around 1,500. Any less choke than that and it dies.

I'm using a cheap compression tester ($30 kit from auto store which included timing light.) so it could be over-reading the compression a bit. I figured that was better than nothing, though.

What's the difference in these carb types? VM? CV?

 

[Big T]

First, congradulations on a successful top end rebuild.

As noted above, clean the jets and the passages in the carbs. No rebuild kit needed, most of them are junk anyway.

You may need some carb gaskets, like for the float bowls. Just order them as needed

Definately go to cycleorings.com and order an O ring set for your carbs and, if Robert has them, the O rings that go between the cylinder head and the intake boot.

Keep posting up your questions as they arise

 

[Nessism]

You’ve done everything else so now do the carbs. Also, change those intake boot o-rings – the ones in your gasket kit will be fine assuming they are the correct size. Get everything together and go ride that sucker. Use a good bit of throttle to put pressure on the rings. Your compression numbers are already outstanding so get those rings to seat properly and your bike should run strong for a long time.

 

[sultan]

Where to find Berryman's?

Where to find Berryman's?

OK, I'm striking out at finding carb cleaner. They still make it: http://www.berrymanproducts.com/Default.aspx?tabid=146
But I've tried Napa, Checker, Auto Zone, and a few other places. (Checked their web sites and phoned also.) It's available on Amazon:
http://www.amazon.com/Berryman-Part..._1?ie=UTF8&s=automotive&qid=1211580860&sr=8-1
but that doesn't help me get started over the long weekend.

Does anyone in the states know where I can get some of this at a retail store?

I think I did see one place that had a "Gunk" brand of carb cleaner. I would assume this would be the same thing?

Thanks.

 

[Nessism]

You don't need Berryman's brand, just get some carb dip. Auto Zone in my area has it so you should be able to find some. Get a one gallon can, and a couple cans of spray carb cleaner as well - good to shoot the passages to make sure the water is out and the passages are open.

 

[catbed]

it is very important to get those rings seated. disassemble those carbs and replace all the orings. clean them real good and set the mixture screws at 2 turns out. dont try and start it un-necessarily because you'll wear out the cross-hatch on the cylinder walls before the rings seat.

 

[tkent02]

I bought a bucket of Gunk, not impressed. It doesn't have that nasty caustic smell that stinks up the house and won't come off your hands, and it doesn't seem to clean much either. I'm thinking maybe the EPA got involved in it.
Figure about a week per carb maybe. If they are not too bad.

 

[waterman]

Actually, I may already have these...I ordered a full "gasket kit" and have 8 pieces left that I couldn't figure out where they went...4 of them are black o-rings of about the right size. The others are small red o-rings of some sort. Or, should I just order ones that I'm *sure* are for this purpose so that they don't melt?) as a matter of course when I take off the carbs again.

I am not trying to throw a monkey wrench into your thread but how big are the small red orings? Was this a Vesrah complete kit? I only ask since I have been down this road and forgot to put the small red orings on the four corner studs at the head gasket. If you look in this post with the head gaskets, you will see these orings (black in this case). The Vesrah are reddish orange.

http://www.thegsresources.com/_forum/showthread.php?t=123898

To me your problem sounds like the carbs need a thorough cleaning, oring replacement and then replace the orings from the intake flanges to head. Robert Barr has both available surely. I would check to make sure previous owner reassembled carbs correctly, I had a slide that was out of position and made the engine race.

 

[sultan]

I am not trying to throw a monkey wrench into your thread but how big are the small red orings? Was this a Vesrah complete kit? I only ask since I have been down this road and forgot to put the small red orings on the four corner studs at the head gasket. If you look in this post with the head gaskets, you will see these orings (black in this case). The Vesrah are reddish orange.

http://www.thegsresources.com/_forum/showthread.php?t=123898

To me your problem sounds like the carbs need a thorough cleaning, oring replacement and then replace the orings from the intake flanges to head. Robert Barr has both available surely. I would check to make sure previous owner reassembled carbs correctly, I had a slide that was out of position and made the engine race.

It's always something, isn't it? Yes, that's what they look like.
Can I assume that the head is going to leak if these aren't in?

Thank you for delivering the bad news. At least I'll have a bit of time to do this while the carb parts soak.

 

[sultan]

I bought a bucket of Gunk, not impressed. It doesn't have that nasty caustic smell that stinks up the house and won't come off your hands, and it doesn't seem to clean much either. I'm thinking maybe the EPA got involved in it.
Figure about a week per carb maybe. If they are not too bad.

So I didn't read your post 'til this morning, but I went to Checker to get a can of Gunk last night. I had *called* this exact store to see if they had Berryman's and they said that they didn't. So I get there, and where the "Gunk" is, I see a can of Berryman's. The tag on the shelf said "Gunk" and the price was the same. The only sticker on the can says "26901", and I think this is what the clerk punched in to ring it up. Maybe this can help someone else in the same situation in the future for cross-reference. The UPC is "0 75894 00996 5" if that helps anyone too. Looks like this is going away, and I was lucky to get this one.