walk me through bench testing floats and needles

[maro]

End of last year, it was recommended by you lovely folks (as I am a newbie) that the reason for my flooding and leaking gas (through vent tube) was due to a stuck needle, potentially. I was encouraged to rip the carbs apart and clean. Well, took me all winter, but I did it, thoroughly.

And like an idiot I struggled getting them back on the bike..without testing them for leaks first. Well, once on, I primed up the carbs last night to start them up, and it looks like I have 2 slow leaks on carbs 2 & 3 (right side top).

Now I've read that I should tighten the screws to be safe, and that I should re-measure float heights. I just measured them 2 days ago, and the needles seemed fine as well. But that was without gas in the carbs.

Once I pull the carbs off again -eerrrrrrrrrr..... how do I bench test this without taking the rack apart.



thanks!!

 

[82Shafty]

To inspect float height, you do NOT need to take the rack apart.

Just remove all bowls and inspect the float heights with your dial caliper.

When your done reinstall your bowls and you're good to rock and roll.

Some guys use fuel line on the bowl drains to monitor the fuel level in the bowls, I will leave that up to you.

If you have a leaky gasket you can A. tighten the screws a bit more, B. get yourself some new, quality gaskets. I can vouch for the OE Suzi ones being of better quality that most kit gaskets I have worked with.

 

[doctorgonzo]

Have heard others say those paper gaskets on carbs can be pretty crappy and work, and in my experience it's true. As long as it's not torn 30 year old originals work fine. Screws are probably too loose. I'd also be replacing with hex screws since you're working on them.

 

[JTsGS650]

Hey maro, dontcha love working on these babys? Do you know where the fuel is leaking from exactly? If it's between 2 and 3 your fuel T may be leaking (?). Is it from the bowl? You may want to torque the bowl screws a bit more to see if you can seal it up. I used fresh Suzuki bowl gaskets during my rebuild, a little pricy at 5 bucks each but I got no leaks.

 

[BassCliff]

Carb info

Carb info

Hi Mr. maro,

In addition to the carb information I have collected on my little BikeCliff website, I also have some notes on bench syncing from Mr. Steve and others. Here are the notes from Mr. Steve. One of these days I'm going to collect all the notes I have on bench syncing carbs and put them on my website. For now, Here's Mr. Steve:
******************

Bench Sync Your Carbs​

By Mr. Steve (Woodin)​

To bench sync the carbs, you do need to have the rack assembled, but not on the bike. Open the master idle speed adjuster until carb #3 has a gap in the throttle plate that is large enough to put something in. That 'something' needs to be small, like a paper clip. Adjust the idle speed adjuster so there is just a light drag on the paper clip, much like you do when checking the valves. You will see adjuster mechanisms between the carbs, so loosen the locknut, adjust the screw so you have the same amount of drag on carb #2, then carb #1. After doing those two (in that order), do carb #4. Now adjust the master idle screw out to close the throttles back down. I like to close them completely, then back in about a turn or two. When you start the bike, be ready to hit the kill switch if the idle speed is still set too high and the engine races when it starts. Back the idle speed screw out some more and start the engine again. When you have the engine warmed up and are ready to do the vacuum sync, use the same order of adjustment.
*******************



Hope this helps.

Thank you for your indulgence,

BassCliff

 

[Steve]

Thanks, BC. 8-[

You just save me a bunch of typing. \\/

.

 

[maro]

Checking the screws is the first thing I'm going to do. Almost positive I torqued'em tight. What's troubling is, from what I've read here, The gas should never even get to the top of the bowls, as the needles should close when the gas lifts the float bowls up. Or is this backwards. Eitherway, it should never get to the top. Maybe my floate heights are just wrong on those two carbs? What sucks is the whole point to cleaning the carbs was to fix a stuck needle. I cleaned EVERYTHING and thought I measure properly!!



oh and...front, sitting on the bike, the leak is on the right top side of carb 2 and the right top side of carb 3.

Hey maro, dontcha love working on these babys? Do you know where the fuel is leaking from exactly? If it's between 2 and 3 your fuel T may be leaking (?). Is it from the bowl? You may want to torque the bowl screws a bit more to see if you can seal it up. I used fresh Suzuki bowl gaskets during my rebuild, a little pricy at 5 bucks each but I got no leaks.

Oh and thank Cliff for bench synch info..... Hopefully I will have the help of a local gsresourcer to help me synch when I get to that.!!

 

[doctorgonzo]

On the carb topic, I've got to find a bike junkyard in this area or start trolling craigslist and get a parts bike. Been watching ebay for a set of 34mm CV carbs for spares and a set finally showed up. They are now over $100.00. Hell for $500.00 I can probably find a whole bike.

 

[Steve]

Hopefully I will have the help of a local gsresourcer to help me synch when I get to that.!!

Hey, I'm only 550 miles straight west of you. Is that "local" enough? :shock:

.

 

[maro]

well Steve, according to your map, you've made this trip before. Let me know when you are on your way, I got plenty of room.

Actually, Duaneage had been nice enough to perhaps stop by my garage tomorrow while in Philly and take a looksey at my mess. He's just a state away.

I would really like to have the leaky carbs fixed for when he gets here, so we can move on to actually troubleshooting firing her up.

So, am I right to assume that the gas should not be reaching the top of the bowl. should I use water to test?

 

[BassCliff]

Hunting, gathering

Hunting, gathering

Thanks, BC. 8-[

You just save me a bunch of typing. \\/

.

Here are some more goodies. This will go in a page on my little BikeCliff Website.
*********************

These are bits of wisdom I have gleaned from posts on the GS Resources Forums. The notes in [brackets] are mine. -BassCliff

Bench Sync Your CV Carbs​

By Mr. Steve (Woodin)

​

To bench sync the carbs, you do need to have the rack assembled, but not on the bike. Open the master idle speed adjuster until carb #3 has a gap in the throttle plate that is large enough to put something in. That 'something' needs to be small, like a paper clip. Adjust the idle speed adjuster so there is just a light drag on the paper clip, much like you do when checking the valves. You will see adjuster mechanisms between the carbs, so loosen the locknut, adjust the screw so you have the same amount of drag on carb #2, then carb #1. After doing those two (in that order), do carb #4. Now adjust the master idle screw out to close the throttles back down. I like to close them completely, then back in about a turn or two. When you start the bike, be ready to hit the kill switch if the idle speed is still set too high and the engine races when it starts. Back the idle speed screw out some more and start the engine again. When you have the engine warmed up and are ready to do the vacuum sync, use the same order of adjustment.

Notes from other members:
From Mr. KiwiGS

• Assemble carbs [in the rack like they are] ready to go on the bike.
• Set air screws 1 1/2 turns from bottom [from lightly seated].
• Determine master carb [#3]. The one that the throttle cable connects to right?
• Put a small drill bit 1.5mm under the butterfly of the master carb.
• Adjust the main idle screw until the butterfly just touches the drill bit.
• Adjust the sync screws until all of the butterflys are the same.
• Check the master carb again.
• Reset the idle screw.

Additional comments from:
Mr. chef1366: I use a flexible feeler gauge [instead of a drill bit]. #3 is the master carb.

Mr. Steve: Start at 2 full turns out and use a smaller gauge. I have had a couple sets of carbs that would not open to 1.5 mm, so I use a straightened-out paper clip. The larger ones I have available at home are 1.05 mm in diameter, the 'normal' size clips are 0.88 mm. Just be sure that there are no burrs on the end of the clip that will scratch the throat of the carb. Also, don't forget to re-set the idle speed before starting the bike. With the throttle open far enough to do the bench sync, revs will tend to skyrocket when started.

Ms. SqDancerLynn1: The only thing I would add is to make sure the #3 throttle blade is completely closed with the idle screw backed out. You never know what was done in the past.

Mr. Steve (again): Ms. Lynn makes a good point. What I tend to do when finished is to back off the idle screw until there is a gap in the adjuster, then shine a light through all the carb throats to verify that they all are closed. Then do a visual sync as I turn the idle adjuster until it touches, then about one turn more.
**********************

Thank you for your indulgence,

BassCliff

 

[JTsGS650]

well Steve, according to your map, you've made this trip before. Let me know when you are on your way, I got plenty of room.

Actually, Duaneage had been nice enough to perhaps stop by my garage tomorrow while in Philly and take a looksey at my mess. He's just a state away.

I would really like to have the leaky carbs fixed for when he gets here, so we can move on to actually troubleshooting firing her up.

So, am I right to assume that the gas should not be reaching the top of the bowl. should I use water to test?

maro, go to this link, DL the manual for our bikes and start reading chapter 5 on the fuel system, I think this will answer alot of your questions and you may be able to figure out your prob with the leaking carbs. Plus it's a great reference to have.

http://www.thegsresources.com/_forum/showthread.php?t=123106&highlight=manual

 

[Steve]

well Steve, according to your map, you've made this trip before. Let me know when you are on your way, I got plenty of room.

Actually, I have only been in the west part of PA on a bike, but that's hard to show with these maps. 8-[

Good thing Duaneage is going to help you, my next two trips will be in the next couple of weeks, and they are taking me to Wisconsin (near Green Bay) and Tennessee (south of Nashville). Anybody need help in either of those two directions. :-k

.

 

[maro]

thanks for the link, I have a clymers, but i dl'd this manual yesterday. Other than re-checking float heights, i can't imagine what else it could be. Hopefully it's just the screws.

UHHG, I am not looking forward to pulling the carbs again.!! So it I just hook up the tank to the carbs while on a bench, I can check for leaks right....I'll just set it to prime?

maro, go to this link, DL the manual for our bikes and start reading chapter 5 on the fuel system, I think this will answer alot of your questions and you may be able to figure out your prob with the leaking carbs. Plus it's a great reference to have.

http://www.thegsresources.com/_forum/showthread.php?t=123106&highlight=manual

 

[doctorgonzo]

Actually, I have only been in the west part of PA on a bike, but that's hard to show with these maps. 8-[

Good thing Duaneage is going to help you, my next two trips will be in the next couple of weeks, and they are taking me to Wisconsin (near Green Bay) and Tennessee (south of Nashville). Anybody need help in either of those two directions. :-k

.

No help (hopefully) but I'm south of Nashville in a town called Murfreesboro. Let me know if you need any info.

 

[JTsGS650]

thanks for the link, I have a clymers, but i dl'd this manual yesterday. Other than re-checking float heights, i can't imagine what else it could be. Hopefully it's just the screws.

UHHG, I am not looking forward to pulling the carbs again.!! So it I just hook up the tank to the carbs while on a bench, I can check for leaks right....I'll just set it to prime?

Did you reuse your bowl gaskets when you rebuilt the carbs? Were they in good shape? Recheck your float heights, make sure all screws are tight and all the gaskets are sealing properly. I'm actually running rich,so I'll be pulling my carbs and resetting float height this weekend as well.

 

[duaneage]

I saw his bike on Friday and we worked on the carbs. I will be sending him some things he needs and we'll get er running soon. I can't bear to see one of our bikes with the guts hanging out in a garage. Perfect weather today too.