I hate these carbs

[Dragonslayer]

The gas mileage on my bike sucked at around 20 mpg, I had two carbs that seemed to be leaking and my last ride the other day the bike ran like crap. So I took the carbs off and apart looking for whatever i could find that might be causing problems. Before taking carbs off i did the float/ fuel level check and the level on three carbs where 3/8" below fuel level mark and the fourth (#3) was 5/8" below.

Took carbs apart, bent tangs on floats down a littlebit, Reassembled carbs put them back on did fuel level in bowl check again and all carbs showed about 3/4" below mark.

That ddn't make sense. Took carbs back off and apart, bent tangs up, put back carbs together, reinstalled did check again and gas wouldn't show in tube for any of the carbs. :doh:

So, I took them apart again bent tangs back down. reassembled, reinstalled did check and bowl fuel level showed 3/8" below mark on all carbs. I figured at this point they were better than they were so I'd try to run her to see if there was any improvement. Put the air box back on and cranked her. Now she's surging and dumping gas on the ground through the four overflow tubes that run down frame to the ground.:bang head:

Did I mention that I really hate these carbs.

Can anyone offer any help?

[Squidley]

There is a precise measurement for the floats and yes these carbs are a PITA, I did Dave Pankows over the winter

There is a mark in the center of the diaphram cover that you need to measure down between 14 to 16MM for the correct float level (It's in the repair manual) Making sure all the diaphrams are good and all your pilot screws are all turned out the same. I'm no carb expert but I know others will chime in and confuse the crap out of you like they did me

[jasonm.]

there is a center mark on both the float bowl and carb body. You MUST have the carb you are working on absolutely level. And measure 16mm below the marks then make your own mark. THEN use the drain opened and a clear hose to confirm the gasoline's height in the bowl...then you are good. Be careful of air bubbles in your clear hose. Do NOT attempt to set the floats with the bowl removed and measuring the floats physical height...this would not be correct.

[Dragonslayer]

There is a precise measurement for the floats and yes these carbs are a PITA, I did Dave Pankows over the winter

 

 

 

There is a mark in the center of the diaphram cover that you need to measure down between 14 to 16MM for the correct float level (It's in the repair manual) Making sure all the diaphrams are good and all your pilot screws are all turned out the same. I'm no carb expert but I know others will chime in and confuse the crap out of you like they did me

So the level should be 14 to 16mm below the mark. Hmmmmmmmmmmmm I was told it should be all the way up to the mark. No wonder I didn't think they were right it sounds like they were right before I started messing with them.

[jasonm.]

16mm below the mark is what the book says....+/- 1 mm. I have 3 of mine right on 16mm. The odd ball is closer to 15mm. But I do not believe it's a big thing on mine. Here's the other pain. Like I said, they must be absolutely level when checking. This is a big pain on the bike. So do a lot of bench checking. You need 1/8" id clear hose. More the better. Have each carb with it's own clear hose and keep them connected. Now you can actually check them on the bike. You'll have to use a small level on the carbs to check before you put the air box on. You'll need to shim the center stand and front wheel to get these spot on. IN FACT you may start it with the air box off and check the reality of how it's working with the bike's fuel system w/the bike running. Had I done the last step all of mine would be 16mm dead on.

[Dragonslayer]

16mm below the mark is what the book says....+/- 1 mm. I have 3 of mine right on 16mm. The odd ball is closer to 15mm. But I do not believe it's a big thing on mine. Here's the other pain. Like I said, they must be absolutely level when checking. This is a big pain on the bike. So do a lot of bench checking. You need 1/8" id clear hose. More the better. Have each carb with it's own clear hose and keep them connected. Now you can actually check them on the bike. You'll have to use a small level on the carbs to check before you put the air box on. You'll need to shim the center stand and front wheel to get these spot on. IN FACT you may start it with the air box off and check the reality of how it's working with the bike's fuel system w/the bike running. Had I done the last step all of mine would be 16mm dead on.

I'm just P'OED I went through all of this and they were right to begin with. Now I have to take off and apart AGAIN to put them back where the were before I started . Down for three days, missed the N. Ga M&E all for nothing. :bang head::bang head:

[BOO]

Little something I've learned through the years about Carbs. They don't usually change much. What I mean is the floats don't change unless something serious has happen like a wreck or something like that, or one has a hole in it. Most of the time the adjustments are fine they just get some dirt in one of the orifices or something. Sometimes Sea Foam will help but most of the time just a good cleaning is all it needs.

Adjusting the floats is a real pain and if you don't understand how to do it you will screw them up every time.

Sorry you were down for so long, been there done that.

Have a good weekend,

BOO

[Guest Fly-N-Lo]

Bob, Terry has your old carbs. I gave them to him at the M&E today.

I feel your pain there. I screwed with mine most all winter. Last nite I had #2 level at 12-13mm #1,3,4 are at 15-16mm. Set all idle jets at 2.5 turns, synced, rode the pi$$ out of it today. After about a 1/2 hour I stopped at McD's and the bike idled at 2000rpm. Lowered to 1000 and took off. She ran great! Rode an hour and stopped and I'll be a SOB if it didn't idle at 2000 again. Reset...and hour later same thing. Keep in mind she ran like a raped ape. Any ideas guys????

[mbrood]

I set my float level sets using a water bowl and a plastic tube on the fuel inlet... just blow slowly into the tube and lower the carb (LEVEL) into the wtaer... when the air cuts off, you have your measurement. I then reassembled and checked against the fuel pump pressure... same reading. So a water bowl is MUCH faster.

 

My four came apart with a perfectly parallel float needle tab (parallel to the float arm), and all four had to be bent in (closer to the float arm) to get the right setting, maybe 10 degrees.

 

While the carbs are out... use the fuel pump and pump about a quart of gas into a glass gar and set it aside to look for bits of grit... even WITH a new fuel filter!

 

With good floats (non-sinking variety), most overflows can be cleared by... open the drain and drain all fuel (the float will now be bottomed), then turn the key on and let it pump a few ounces out the drain (flushing the needle seat), then turn the key off, and close the drain... now turn the key back on and watch for overflow.

[Freebird]

Boo, I agree that they probably don't change much but I can tell you that Yamaha doesn't go to great pains to get them right to start with. Of the 5 or 6 people I know that have checked their floats on the RSV, all have been off pretty badly. None have been consistent from one carb to the next.

[jasonm.]

Dragonslayer...what prompted you to play with the floats in the first place? I know we cannot go back in time. But I am curious. Were they leaking even before you touched them? If yes, then you may need new needle seat assemblies. I had 2 needles go bad. They are rubber and they dry out. The seats are brass and really do not go bad. So just changing the needle fixes things. Unfortunately you have to get both needle and seat from Yamaha @ $30 each set.

[BOO]

Boo, I agree that they probably don't change much but I can tell you that Yamaha doesn't go to great pains to get them right to start with. Of the 5 or 6 people I know that have checked their floats on the RSV, all have been off pretty badly. None have been consistent from one carb to the next.

 

I definitely agree that they probably are not right a lot of times from the factory, I was assuming the bike to be running okay before the adjustments. I guess what I was really trying to say was most people should keep their fingers out of the carbs. Adjusting the floats are not as easy as it sounds. I can do it but I sure don't touch them if I don't have to. Sort of the same goes for Sync'd carbs, I'm not sure why people have to do that so much, I'm not sure what is changing to cause the balance to change.

I can say I don't hate carbs but they can be a pain.

Hope everything is going good for you,

BOO

[Dragonslayer]

Dragonslayer...what prompted you to play with the floats in the first place? I know we cannot go back in time. But I am curious. Were they leaking even before you touched them? If yes, then you may need new needle seat assemblies. I had 2 needles go bad. They are rubber and they dry out. The seats are brass and really do not go bad. So just changing the needle fixes things. Unfortunately you have to get both needle and seat from Yamaha @ $30 each set.

I went thru the carbs last spring right before Daytona and ever since then I've been getting gas overflowing and running down the carb bodies on on the two rear carb bodies from the air box boots. Gas mileage has been lousey at about 20 mpg. I've also been fouling plugs lately so I'm thinkin it's running rich and float level to high on rear carbs waisting gas. I also was under the impression or misunderstanding that fuel level in bowl was supposed to be up to the mark which they were not. That's why I took the off to adjust float level.

[jasonm.]

I definitely agree that they probably are not right a lot of times from the factory, I was assuming the bike to be running okay before the adjustments. I guess what I was really trying to say was most people should keep their fingers out of the carbs. Adjusting the floats are not as easy as it sounds. I can do it but I sure don't touch them if I don't have to. Sort of the same goes for Sync'd carbs, I'm not sure why people have to do that so much, I'm not sure what is changing to cause the balance to change.

 

I can say I don't hate carbs but they can be a pain.

 

Hope everything is going good for you,

 

BOO

resyncing the carbs is needed due to the carb linkages, left to right wearing and the engine's intenals also ever so slightly wearing. Which in turn changes vacuum to the carbs. But mostly it's the linkages. Dragonslayor , I feel your pain. I may have to pull my carbs also. Due to my not so perfect rebuild...As it looks now with mine. I should have changed more than just the internal gaskets.

[greg_in_london]

A couple of points:

• Yamaha messed about with their recommended fuel levels over the different models. A couple of the relevant models are in a table at http://www.venturerider.org/forum/showthread.php?t=20950&page=9 - in other words check the manual for your model.
  
• 3/8" (about 9mm) is too high a fuel level -in fact it is close to the overflow level. (The lower the number the higher the fuel level.) The one carb at 5/8" was the only one close to right.
  
• You can check the fuel levels reasonably accurately with the carbs off, with just a fuel container connected.
  
• While they are apart, you probably will find a float height that you can physically measure - check what the fuel level is on the carb closest to the correct level and then measure the height with the bowl off. Then you'll have a figure to aim at. [sorry - I've not done mine for a while and don't want to guess a wrong figure.]
  

Oops - that wasn't a couple.

[sofapilot]

:stickpoke:

 

Umm excuse me for a minute while I go out in the garage and hug my fuel injected H-D

 

sorry just had to....

 

[eagleeye]

Dragonslayer, I'll just add this about the carbs, and I'm cerainly not a carb expert, but I did have the carbs apart on my 05 RSTD, and found white buildup from ethenal. Now, to see this, you will need very good magnification. If you do find this, you will need to clean it all off.

It's something to look for while your in there. Can't help you with the float level though.

 

Steve

[Squidley]

:stickpoke:

 

Umm excuse me for a minute while I go out in the garage and hug my fuel injected H-D

 

sorry just had to....

 

 

 

I expect nothing less from you Phil, good to see your face on here

[sofapilot]

[Freebird]

I don't know Squidley...we haven't seen any pictures of the supposed Ultra Classic. I wonder if it really exists.

[Dragonslayer]

Dragonslayer, I'll just add this about the carbs, and I'm cerainly not a carb expert, but I did have the carbs apart on my 05 RSTD, and found white buildup from ethenal. Now, to see this, you will need very good magnification. If you do find this, you will need to clean it all off.

It's something to look for while your in there. Can't help you with the float level though.

 

Steve

Thanks for the advice, I did not notice any of this when I had the carbs apart. In this area there is only about one station in ten that has 10% ethanol gas.

[Dragonslayer]

I musta done something right this time, because when I took them back apart and adjusted the float level adjustment back to parallel to a slight angle down less than 10% and then put it back together.It stop pouring gas out the overflow tubes, seems to run and idle OK. And it now runs like a(To use Fly-N-Low's vernacular) RAPPED APE. Much improvement.

I guess the new spark plugs and getting the airbox seated properly on the carb throats probably didn't hurt much either. I don't have enough miles on it yet to comment on gas mileage.

[Squidley]

I don't know Squidley...we haven't seen any pictures of the supposed Ultra Classic. I wonder if it really exists.

 

 

Well we really didn't see Russell on a Venture either....you might be on to something here Buddy

[Dragonslayer]

Well we really didn't see Russell on a Venture either....you might be on to something here Buddy

 

[jasonm.]

FYI- Gas coming out the over flow tubes means the float chamber is absolutely full. These carbs need only to be 1/4 full to function. Also the ethanol is common around here now for 8 years. The stuff absorbs water and the white you see is the aluminum of the carbs corroding due to the amount of h2o that lives at the bottom of the carbs. Take ethanol gas, poor 3 oz. into a clear glass in summer on a mildly humid day. Set it outside. Come back 1 to 2 hours later...result>enough water at the bottom to spawn water bugs. New gas is junk!