Off the Deep End

[Flaggo60]

So I can't avoid it any more-its official, I can't rely on pro mechanics to maintain my '81 GS650G anymore, they just won't spend the time. Just dropped $150 for absolutely no improvement. No. 2 cylinder not firing, still. Everything else OK, carb blockage methinks.

Hoped to avoid any major work til winter. Ain't gonna happen, so here I go. Carbs will have to come off and be rebuilt. Daunting task to me, I'm an architect, not an engineer. I don't want to end up with my bike in three bushel baskets going on EBay for ten bucks.

Still, there's lots of good info here including the GS Carb Cleaning and Repair Pictorial and I have the manual, so wish me luck. Here we go-Wheeeee.

 

[Draketh]

Don't get intimidated. I bought my first bike about a month ago and it was running like complete crap. About a week of reading, finding this forum, and preparing and I yanked the carbs out and cleaned them myself. I got a carb rebuild kit online, bought a bucket of chem dip, couple can of carb cleaner, and ordered two new air box boots.

I got everything back together Saturday and took it around the back streets to make sure everything got back together right. I bought insurance and got my plate yesterday and went out for an all day ride and had an amazing time.

If I can do it so you can you! The hardest part is probably going to be getting the carbs back on the bike to be honest, that part made me want to dump the bike in the driveway and go have a beer or ten.

I knew nothing about bikes when I got mine and have always been a computer guy seeing as its what I do for a living but I got through it and everything came out great in the end thanks to the wonderful people on this forum. If you have questions don't be afraid to ask there will always be someone here to help.

 

[rustybronco]

Daunting task to me, I'm an architect, not an engineer.

So how many of us do you think are?
you have one up on me Mr. architect, I sell auto parts.

I don't want to end up with my bike in three bushel baskets going on EBay for ten bucks.

I do!, um how far are you from Sarnia?
kidding....

 

[flyingace]

So I can't avoid it any more-its official, I can't rely on pro mechanics to maintain my '81 GS650G anymore, they just won't spend the time. Just dropped $150 for absolutely no improvement. No. 2 cylinder not firing, still. Everything else OK, carb blockage methinks.

Hoped to avoid any major work til winter. Ain't gonna happen, so here I go. Carbs will have to come off and be rebuilt. Daunting task to me, I'm an architect, not an engineer. I don't want to end up with my bike in three bushel baskets going on EBay for ten bucks.

Still, there's lots of good info here including the GS Carb Cleaning and Repair Pictorial and I have the manual, so wish me luck. Here we go-Wheeeee.

Most here knew as much as you when they started. You learn by doing and osmosis.

Pull the #2 plug after it's run a bit. The plug tells you a lot. Is it dry? Then you are right about fuel blockage. Is it gas wet? Then maybe that plug isn't firing. Is it oil-soaked? Then possibly bad rings. Is it black and sooty? Then #2 cylinder is running way rich - possibly a fuel petcock problem.

Look at the plug and update the thread with the info. It will help diagnose the problem.

 

[Nessism]

Rebuilding your carbs is the GS right of passage. You are in good company.

A few tips:

Unbolt the airbox and slide it back as far as possible before wrestling with trying to get the carbs in/out.

Order an O-ring kit from cycleorings.com

Order carb boot O-rings and new screws from cycleorings.com

Order float bowl gaskets if yours don’t come off in one piece – order up front if you are in a hurry.

Most newbies try to shortcut the rebuild process and wind up having to redo the carbs again and again until they get it right.

Carbs should be vacuum sync’ed after the rebuild job.

Replace the fuel line and vacuum line while the carbs are off (I recommend using stock line, not automotive line, since it’s more flexible and has a smaller OD).

Make sure the gas tank is clean or rust will contaminate your fresh clean carbs.

If you choose to use a fuel filter, get the kind with the stone on the inside since this type is designed to flow at low pressure.

Pilot screws should be set to 2.5 turns from lightly seated for a start. Tweak them further – out is richer – as needed to achieve the highest idle speed.


Good luck.

 

[Flaggo60]

Most here knew as much as you when they started. You learn by doing and osmosis.

Pull the #2 plug after it's run a bit. The plug tells you a lot. Is it dry? Then you are right about fuel blockage. Is it gas wet? Then maybe that plug isn't firing. Is it oil-soaked? Then possibly bad rings. Is it black and sooty? Then #2 cylinder is running way rich - possibly a fuel petcock problem.

Look at the plug and update the thread with the info. It will help diagnose the problem.

Pulled the plug and it was bone dry. Plug is fairly new and was firing. Dirty carbs seems the most likely as they've never been done.

 

[doctorgonzo]

You'll be fine.
Use the pictorial guide
Use bags or boxes, or egg cartons something labeled for contents.
Use a system of placing always same spot on table or something for which carb is which. You can mark them but it will come off in the dip.
Take pictures of before you take each thing apart like the choke actuator, etc...
Go slow
Go slow
Get a good screw driver (the bits from my impact driver work well) for taking them apart.
Replace with allen heads while you have them apart.
Go Slow

 

[Flaggo60]

So how many of us do you think are?
you have one up on me Mr. architect, I sell auto parts.

Didn't mean to tick you off, was referring to Star Trek quote from Bones, "Dammit Jim, I'm a doctor not an engineer". Sorry

 

[Draketh]

Pulled the plug and it was bone dry. Plug is fairly new and was firing. Dirty carbs seems the most likely as they've never been done.

You might as well do the whole shebang while your at it. In addition to cleaning the carbs replace the vacuum line, empty the tank, wash it out, let it dry, take a look inside with a flash light and make sure its not all dirty/rusty. It's up to you if you want to treat the tank or not but done right it will save you a headache. Replace the fuel line too and see if you can't get an inline filter as you don't want your freshly cleaned carbs getting all gummed up again. While your at it depending on how bad of shape they are in you may want to replace the air box boots, clean the air box element, grab a new oil filter, give her a change and get back on the road. Depending how bad the carbs are they may not need to be dipped, I know mine didn't. I just had a 100% plugged jet. If your carbs don't need to be dipped this is pretty much an afternoon of work and then you'll be back on the road.

 

[Flaggo60]

Thanks for the positive responses, all good info. I'll update as I go.

Cheers

 

[doctorgonzo]

So how many of us do you think are?
you have one up on me Mr. architect, I sell auto parts.

Didn't mean to tick you off, was referring to Star Trek quote from Bones, "Dammit Jim, I'm a doctor not an engineer". Sorry

I can't answer for him, but don't think he was ticked off. More just saying don't underestimate yourself. You're obviously, in your profession, a technical, detail oriented guy (I'm a computer programmer). It's a very methodical, precise, step by step process, not unlike what you do every day.

 

[rustybronco]

So how many of us do you think are?
you have one up on me Mr. architect, I sell auto parts.

Didn't mean to tick you off, was referring to Star Trek quote from Bones, "Dammit Jim, I'm a doctor not an engineer". Sorry

God I wish we still had smiley's (no I don't need an alternative source). Heck no i'm not ticked. it was a light hearted response, meaning I ain't gotz me no higher education.
don't know if that was a quote by dr. mccoy...

***edit*** Just because I didn't go to "college" doesn't mean I haven't done/worked on clocks, watches, computers, radio servicing (first place in the state!), everything on/in a car including panel replacement, diesel engines, tractors, painting, build/crew chief two race cars, make cabinets.... the list is long and I'm old....
***edit-2*** smiley's back!!!

Carbs are just one more thing to add to your resume when they're done. are they off yet? : - )

 

[Flaggo60]

I must have been cranky after realizing I just spent $150 on nothing to learn #2 was still out.

Usually my sense of humor is pretty good ...

I want to wait until I have plenty of head scratching time to start the work. I'll be free to start after the middle of July.

"GO SLOW"
"GO SLOW"
"GO SLOW"

Thanks again to all and I will be back in touch.

 

[flyingace]

I have a related question. If the #2 carb float needle was stuck closed, would that carb have no fuel, or would the balancing tubes between the carbs fill the bowl? I've often wondered about the purpose of those tubes since each carb has it's own needle/float.

 

[rustybronco]

Flyingace,
Consider them a common fuel rail that feeds fuel to each needle and seat, the needle in each carb allows fuel to fill each bowl as needed.
kind of like if you had a water pipe that had four spigots, that you could open as needed to water different zones of the lawn. if you kept one closed... no water that part of the lawn.

 

[robertbarr]

I have a related question. If the #2 carb float needle was stuck closed, would that carb have no fuel,

Correct, the bowl would be empty. There are two sets of interconnecting tubes. One set is to feed fuel to the carbs (upstream of the inlet valve). The other set is a vent path, to keep the inside of the bowl at atmospheric pressure (just like the vent plumbing in your house).

 

[flyingace]

Well, is the correct answer behind door #1 or door #2?

Winner! - I have to go with #2. It is a common fuel inlet passage, not a common fuel leveler. The line is above the level of the inlet valve.

Now, this opens the possibility that the needle valve is stuck shut and there is no fuel in the #2 bowl.

The question to the poster is: does the cylinder not fire only at idle/just above idle, or not fire at any engine speed?

 

[82Shafty]

I was going to say gee whiz, we can't all be Master Tech's. The funny part is I deal with architects on a daily basis as my Clark Kent position as Project/Operations Mgr. for FF&E.

I only bust out the Master tech, L1 card when some service writer starts to lip off to me on servicing company equipment.

As far as carb advice, keep needles and seats together, so in otherwords, what you take out of one carb, make sure it stays with that carb!

The tutorial does a good job of walking you through the rest. You know where to go if you have any questions. The nice thing for me I was the fact that I was able to stop by Robert Barr's house to get my quality rebuild kit for those spur-of-the-moment rebuilds.

 

[Steve]

You'll be fine.
Use the pictorial guide
Use bags or boxes, or egg cartons something labeled for contents.
Use a system of placing always same spot on table or something for which carb is which. You can mark them but it will come off in the dip.
Take pictures of before you take each thing apart like the choke actuator, etc...
Go slow
Go slow
Get a good screw driver (the bits from my impact driver work well) for taking them apart.
Replace with allen heads while you have them apart.
Go Slow

All of the above, and my wife gave me a present when I started working on another set of carbs.
She came home from the dollar store and said, "will these work for you?"

Yep, disposable muffin tins. Two of the 6-place tins in a package for 99 cents.
Spread four of them out and you have one tin for each carb. No problem keeping stuff straight.

.

 

[Flaggo60]

Yep, disposable muffin tins. Two of the 6-place tins in a package for 99 cents.
Spread four of them out and you have one tin for each carb. No problem keeping stuff straight.

.[/quote]

Great idea! Thanks.