getting float needles to seat right

Trying to get my linearization down regarding issues with fuel levels and metering on my 82 650 maxim. Seems like a familiar problem on the boards lately, and there's been plenty of useful info to refer to. So i thought I'd write up where I'm at and see if anyone had some ideas, maybe someone else had the same issue

Carbs are thoroughly cleaned, float height set and double checked with the clear tubes, bench synced, then carbs reinstalled. Fresh fuel in the gas tank, new vacuum tube hooked up to the correct nipples. The bike starts and runs, before starving out and dying. On the bike with the tubes, I can determine at least one bowl isn't getting enough fuel. Whacking carb bodies doesn't help. I can prime the bowl up to the right height, by eyeballing the tube, and then start the bike and it will run just fine for a few minutes before starving and dying. Leaving it on prime then massively flooded out the carbs, subsequently requiring an oil change. haha my bad.

I was confident the float height was set correctly on the bench but given flooding the height is the obvious thing to recheck. Beyond that...

I polished the float pins, and the needles and seats were all replaced. I might have accidentally magnetized the float tangs with needle nose pliers while setting them... would that somehow cause the pins to hang up and not land right in the seats? it didn't seem to me that there would be any other local material for a magnetized float to react to, but maybe there is.

The fuel tap doesn't leak and works all too well on prime, but not enough fuel reaches the carbs when in the "on" position. No debris whatsoever on the seat beanies, the fuel pipe is clear. So is this more likely a vacuum issue or a fuel tap rebuild? I checked for air leaks with wd-40 and couldn't get any engine response from it.

So thats the long version. I'll be working back through it in a day or two, but let me know if anything jumps out at ya

 

Is your petcock working properly? Try it in the prime position. Also unlock your gas cap just in case the vent plugged up see how it works

 

You have to set the floats with the rack off the bike, "mounted" level front to back and side to side, and use the "clear tube method." Dry setting isn't a good test, it only gets you in the ballpark.

It also sounds to me like you have a petcock problem as well.

 

the vacuum line to the petcork doesn't leak or collapse ?
take the fuel line off and the vacuum line then suck on the vacuum line
and see what kind of flow you get. don't get the fuel and vacuum lines mixed up when you suck !

 

If you do, make sure you have a couple of olives handy, that way you can have an unleaded "Martini"! :roll:
:twisted: :twisted: :twisted:

 

just got back to it today, its lame not having a closer garage to work in. lol with olives nearby, i sucked on the vacuum tube and its working just fine, it draws gas with little effort. The petcock is a little drippy and should be rebuilt, but not leaky enough to be the big problem right now.

so properly set carbs should be flood-proof, right? as in able to tolerate prime, or at least hold back a reasonable amount of fuel in the rail and line after they reach the level they are set for? carb number two is just refusing to hold its level right. i thought i had all the heights down pat when i wet-set em on the bench last time, but tonight i pulled them, stuck em on the bench, and verified that number two constantly floods out no matter what setting- probably why number four was always starving dry when idling.

again, clean new needles & seats, screwed in securely, polished float pin, and intact floats that float, proper side up. To test I set #2 float height way low, and still flooded. I even swapped out floats and needles with a working carb, and it still flooded. pushing up on the float with the bowl off does indeed stop gas flow, so the needle must be seating right. so yeah, hard to know where to go at this point beyond starting over and rechecking everything. blarg. thanks again for all the info

 

...aint old bikes FUN????????????

 

did you check to insure that one float isn't upside down?

Also you say the bench sight tube test shows correct, is it possible you might not have been at true level...that got me recently...same senario.

Your saying you set float #2 real low...but still hits overflow...not sure but how can you tell which carb is hitting overflow..they are connected overflows.

 

You polished the float pins, but did you roll up a bit of ultra-fine sandpaper and polish the INSIDE BORE of the float, where the pin resides??

And you were thinking that it got magnetized? Enough to pick up staples, or little nails?? If you set a float low, you're going back in.

 

it floods out from the air intake port on the carb body, on the bench in vices. this is the only carb that does this. how are the overflows connected? all floats installed and set flat side toward bowl/ meaty side toward carb per the manual. that would be an easy thing to overlook though.

that'll be the next thing to check. float action seemed smooth just messing with it on the bench, but thats one more thing needing to be ruled out. they are slightly magnetic now, but not picking up any metal debris that i can see. any issues with the pin being a little loose in the float pillars?

my brother likes to say theres nothing wrong with this xj that can't be fixed with a shotgun

 

my brother likes to say theres nothing wrong with this xj that can't be fixed with a shotgun [/quote]

Is he talking XJ's or Ex's, be a shame to draw down on an innocent motorcycle. :roll: :roll:
:twisted: :twisted: :twisted:

 

don't think he means it but i make sure the bike isn't in earshot... not gonna risk any more hurt feelings, last time it got mad at us i got a crankcase full of gas.

 

You can NOT take short cuts....You need to set them on the bench, level, WITH GAS flowing into them. Anything else, you are just wasting your time.

Clamp them level. Get a test tank or some method to put fuel into the inlet hose and use the clear tube method posted many times.
The bowls can be loose or my favorite method of using a rectangular glass that fits under the floats.
With the bowl held on with one screw finger tight, gas should not over flow the top or you need to take it off and re-adjust anyway.

 

Hey just a follow-up- adding a fuel filter to the line with which i was wet-setting the floats on the bench made all the difference. I'm using a radiator overflow tank as a cheap aux tank. Its really convenient, but i guess it flows fuel a lot heavier than a petcock would. and the extra fuel force was hammering the needles into flooding? thats my theory at least, the filter helping slow the gas flow down a bit. carbs are now back on bike with no flooding, cold starts right up, throttles smooth with no hanging and idles steady at about 1200 rpm with little choke. ran it for about ten minutes and it runs better than it has in a year. so if i can keep the gremlins out of the floats, i think i can keep moving forward. thanks again xjbikes.com for existing

 

If a filter is the best explanation you can come up with, then I suspect you haven't seen the last of the gremlins. :lol: I suspect that your #2 float or needle is intermittently sticking for some reason. I think the filter is a red herring.

If it's working right now, then I'm not sure I would go back into it unless it comes back again, but that all depends on if you're a gambling man or not. If you do decide to go back in...

Look for alignment of the float in the bowl? Not bent and slid to one side?
Look for rub marks on the inside of the bowl where the float may be hitting it?
Look for rub marks on the inside edges of the float towers?
Look for bent float towers?
Put the float pins on a flat surface and make sure they're straight?

All else fails? Move the problem float and valve to a different carb and see what happens? You'll have to reset the levels, but it might provide some insight.

Until then, carry a screwdriver and small mallet with you to rap on the side of the offending carb body to dislodge a sticky float, cause you KNOW it's gonna happen at the most inconvenient time and you aren't going to have any tools with you!

 

so what you are saying is the float needles need to be clunk tested? LOL