Fussy Floats

Sorry for another long post, but I'm out of ideas, and I could use a little more guidance!

My bike is now finally running, I've torn apart/cleaned/rebuilt the carbs, bench synched, bench set my float heights, reinstalled and adjusted the carbs, and now have floats that occasionally work.

When I hook up some tubing to check the float heights, the fuel levels are dead on.

However, if I leave the bike sitting for 2 or 3 days, I guess the fuel evaporates from the bowls, so I have to turn it to prime for a few seconds. I then put it back to on and start the bike, and everything is great, until the fuel starts to drown the engine, and it begins to sputter .

If I pull the vacuum tube to the petcock, the sputtering stops and normal idle resumes after the excess fuel is burned off. When I reconnect the line to the petcock, it will run fine for a while until the bowls start to overflow again.

I can then pull the carbs, and check the levels again and all will be back to normal. I reinstall the carbs, and they work again, until I leave the bike stationary for a few days, and then we start all over again.

Do new float valves take a while to "break in"?

The float valves and seats are new units from Chacal, all the floats float at the same level when placed in a bucket of gas, the pins have been cleaned and polished, I even tried the Golf Tee method of de-burring the float seat, and they still act up.

Its a pain to have to fiddle with these things every time I want to go for a ride, although I must say that I am getting pretty good at removing and reinstalling the carbs :roll:

I would gladly take has any suggestions you guys may have!

 

I had same problem last year when i replaced float valves, my problem was dirt in the tank.

I installed inline filter and didn't seem to have anymore problems.

not sure if this is your problem, I keep finding dirt in the carbs every time I took it apart.

 

If your carb bowls are emptying from evaporation in just 2-3 days then you have an air leak somewhere or the fuel is dripping out.

Is your bike inside or outside? If its outside, bring it in overnight and check for drips on the floor and for gas fumes.

I can leave my bike for a week and it fires right up.

My bike is an exact year/model duplicate or yours.

 

Longshoreman, I've had a fuel filter inline since the carb cleaning, so I doubt its dirt contamination.

Half, the bike has been indoors at the warehouse, no fuel drippage on the floor, and it's not going into the crankcase either, my oil level has been the same since I filled it. My guess is that the warm air indoors may be helping it evaporate faster than it would outside.

Thanks for the advice guys!

 

I read with interest all the steps you took to troubleshoot the floats. Good work.

I have an XJ750 Seca that is still in the barn. It now runs and I am about to paint. But 1st, I took it for a quick one mile test ride. I used a portable gas bottle with volume markings and consumed 4 oz of gas! I let the bike cool, filled the bottle and watched the level. I lost 20 cc of gas in 2 hours.

Did you ever find a satisfactory answer to the problem?
Thanks, Greg

 

If this Problem persists ... do a couple of things.

Eyeball the Geometry of the Float Pin being raised and lowered. You might have to swing the Wire Clip on the Float Pin to the other side of the Tang to get it to rise and fall perpendicularly.

The Float Body might need to be "Dressed"
Roll-up a strip of 1500 or 2000 Finishing Paper and Polish the Valve Body Bore.

If the Float Pins that came with the Rebuild Kit are NOT Solids ... But, Neoprene Tipped and Spring Loaded ... DRESS the Valve Body Bore with 2000 anyway!

 

My XJ is the same 4, 5 days without riding and I need to switch to prime before starting.
I don't worry about it anymore.

 

Thanks for all the advice guys, looks like the trick may be the polishing like Rick suggests.

This afternoon, I pulled the carbs and checked the float valves again, and there was a little bit of anti-sieze in there, but I don't know if that could be the culprit. I cleaned everything out, reassembled, and decided to try the blow test.

Just like on the bike, it seems that once in a while they will not seat fully, I give the carb rack a good shake, and suddenly I can't blow any air out. Flip it over, shake around a bit, and they will leak again.

Even when I think I understand the house of clean, it seems there's always a little more polishing and shining to do! These are the neoprene tipped valves with the springs, and I do notice that one in a while the springs can get stuck.

By the way, I finally got the bike inspected and put my first 22 miles on the bike after work, must say this thing is a blast! I still have a hanging high-idle to figure out, but I hope that fine tuning and another round of carb synching will cure my bike!

Thanks again for all the help guys!

 

After reading Rick's comments about dressing the seats...I pulled the carbs out. Not a spec of dirt in the bowls or in the recovered gas.

The float valve/needles are neoprene tipped so I can't imagine leaks there. (Inspected under magnifier and neoprene is complete) The seats absolutely brightened up when I used fine steel wool and the golf tee to get down in there.

The copper washer is worn. It suddenly dawns that there could be seepage past the washers. I will try finding some fabric washers locally.

LASTLY - There has GOT to be a measurement to set the floats with the carbs off the bike. Can't believe you have to install-uninstall to set levels. Somebody tell me the secret!!!!

If this all fails, Chacal sent info and he is my next call.

Thanks, Greg

 

Read Rick or Chacals carb cleaning threads.
I don't know what bike you've got, put it in your sig.
IIRC dry the float is 17-17.5mm from carb body to float.
Then on the bench with carbs level attach clear tube to the bowl and fill.
All levels should be the same in the clear tubes.
Like I said "Read Rick or Chacals carb cleaning threads", it is layed out step by step.

 

I have a XJ750 Seca.

Great idea to assemble and fill on the bench. The shop manual says to run the engine, shut down and then recheck levels...but allowing some gas to drain out and then re-equalize the test level tube while on the bench will also work fine.
Thanks, Greg

 

Have a close look at all the tangs on your Floats, what I found was that the spot where the Float Needle Pin sits was fretted slightly causing the Float Needle to hang up in the valve. Blend the tang with a small piece of 1000 "Wet & Dry" and some WD40 to remove any lip and provide a smooth surface for the Float Needle pin to move on.

I also polished the inside of the Valve body with metal polish until it shines using a Q tip.

 

That's what you have to do.
Strive for perfection.
Eyeball the Geometry of the Float as it sits above the Float Valve Body.
If there's too much end-play of the Float on the Hinge Pin ... Shim it with Pilot Mixture Screw Washers.

Bring one on to a well stocked Hdwe Store and pick-up $0.20 cents worth.

 

I didn't have a chance to try any of the tips today, but I think I'll go and get some 2000 grit paper tomorrow and attack these floats a bit more.

Kiwi, that's a great idea, I didn't even think to check how smooth the float-rest surface was, I'll have to give that a good buffing as well.

Rick, I do believe there was a little side play, I'll have to see if I can get my hands on some really small washers tomorrow to try and remove any slack.

Well, guys, I certainly appreciate all the kind advice, I hope in the next day or so I can report back that float issues are behind me, and I can move on to the next adventure that is certinly lurking in the shadows!

 

These floats are beginning to become a pain in my back side :evil:

I polished the valve seats, float pins, float pin guides, and the tangs on the floats all with 2000 grit paper. I even re-tried the golf tee in the valve seat.

I tried blowing through the gas line again while upside down, and like before, occasionally one or two will not close completely. It isn't always the same valve either all four of them will occasionally stick open.

Has anyone else had problems with the aftermarket valves/seats? If it weren't for the one that was missing the tip, I would be tempted to put in my old valves and seats. As old and hardened as the tips were, those valves didn't leak.

Oh well, I guess the carbs will be coming out and apart again.

 

I have read a thread here where a cheapo eBay rebuild kit caused big problems. You should only buy from Chacal or you local Yamaha dealer.

 

That's the thing, I bought the carb lower end rebuild from Chacal, part number HCP2776. I know it's not the OEM version, but is it as bad as the ebay ones?

 

Lift the Float and the TANG engage the WIRE on the FLOAT NEEDLE.
If the Wire Clip prevents the Needle from Rising and Falling straight Up and Down ... Put the Clip on the Opposite Side of the Tang and try that.

If you need too ...
Get a Pair of Jewelers Wire Bending Needle Nose Pliers and CHANGE the BENDS in the Float Needle Clip ... to allow it to have additional PLAY so that the FLOAT PIN will Rise and Fall without the Wire touching the TANG ... (Just surrounding it) ... NOT touching either side of the TANG.

 

Chacal would not sell junk. His stuff is top flight.
Just follow RickCo's advice and get your floats working.
I used RickCo's carb cleaning write-up in the FAQ and after about a day and a half of work my carbs work flawlessly. I was fortunate that my floats and tangs and needles are all in good working condition and just needed to have years of crud flushed out. My carbs pass the clunk test. I did the float check on a bench using blue windshield washer fluid.

 

If the Wires on the Float Pins are designed for "Skinny-Tangs" and you have Floats with wide "Fatty-Tangs" ... the Float Pin end-wire is going to cause the Pin to be "c@ck-eyed" and possibly bind.

Hold-up an Old Float Pin and a New one side-by-side and see if the Wire Clip is the same dimension. If not ... use some precision tools and fashion the New Wire to be the same as the Old wire.

 

Thanks for the help guys, I guess I'm just a little frustrated because this is the only real thing holding me back from riding!

Rick, I'll pull the carbs off again, and take a look at the tangs. I'll try to bring the camera along so I can get a few pics for you guys to examine, it doesn't hurt to have a second opinion from someone who knows what they're doing!

 

Guys
Hope this will encourage all. I pulled the carbs, polished needles & seats with 0000 steel wool, replaced one float with apparent cracks, used fiber washers on the float valve body and lastly, set the float levels at 4 mm below carb body.

It appears to have stopped the leak by. no performance issues at WOT. Don't give up pederacer.

The last area is fuel usage. Still appears to be running rich. The vacuum line is plugged while I use a temporary gas bottle. Hate to ask a stupid question...does the vac line have anything to do with the high fuel use?

Greg