Problems again

tz375 · Post by **tz375** » Sun Jun 21, 2009 5:34 pm

Everything points to an air leak or pilots too small, but you checked for leaks and upped the jets.

So that leaves a slight leak in either an intake gasket of a base gasket - or maybe a spec of dirty managed to get lodged in the pilot circuit somewhere.

Is it possible tha there's a partial blockage in the float bowl where it feeds gas to the pilot jets?

Coyote · Post by **Coyote** » Tue Jun 23, 2009 9:11 pm

I went to the dealer today and ordered 3 new intake rubbers. I want to take that out of the equation when finally dialing it in. Also recieved a set of 3 over pilots today. Seems like wat too much. Intake pipes first, then go from there I guess.

Coyote · Post by **Coyote** » Thu Jul 02, 2009 5:27 pm

I put the new intake pipes on today. No change whatsoever. I tore one of the old ones apart. There is a liner betwen the inner rubber and the outer rubber. Esentially they can't leak air even if they are cracked. You have 2 layers of rubber with a dense mesh liner sandwiched in between. The probability of getting a crack in the outer shell, tearing the super tough liner and having a crack on the inner shell all lined up is about a billion to one. Don't throw your money away on new ones like I just did. If the spogot ends are good, use em.

jaybob · Post by **jaybob** » Thu Jul 02, 2009 6:09 pm

Awww Chris. It's never a waste to put new parts on the old girl.

Coyote · Post by **Coyote** » Thu Jul 02, 2009 6:26 pm

After further evaluation, the liner acts as a buffer between the outer and inner shell. This eliminates them ever leaking air - even if the outer shell gets dry rotted and cracked. Remember these were designed to last the life of the motorcycle and it's an ingenious design at that.
No where in the scheduled maintenance will you find "inspect intake pipes for cracks and replace as necessary".

TitanRider · Post by **TitanRider** » Thu Jul 02, 2009 6:28 pm

I chased an air leak on my 500 that turned out to be a torn o-ring on the air screw.

Coyote · Post by **Coyote** » Thu Jul 02, 2009 9:43 pm

OK. So let me ask you guys this. Between the center carb and the outer carbs there are a pair of nylon 'Ts'. These are on the upper most forward lines that connect the carbs together. What is their function?? I tried capping them off and it seemed to make matters even worse. Are these just simply vents??????? The fische shows nothing attached to them and they have no part number........................ Mine are pointed downward at about the 7 o'clock position.

tz375 · Post by **tz375** » Thu Jul 02, 2009 10:28 pm

Sorry it wasn't the tubes.

But it still sounds like a lean mixture.

Is that Tee the vacuum hose connection or is it the float bowl breather?

All my pics of 550s are on the main PC with a dead monitor, so I can't see them.

Your comment that it made it worse to block them off is interesting. That doesn't sound like a vacuum connection. Do you have a spare carb to check out where they go? That may point us in the right direction, but it could also be another red herring.

So if its absolutely positively not an air leak, it must be a fuel problem and if it only impacts the bottom end it must be some sort of restriction in the fuel supply.

You changed out the jets, so it is extremely unlikely to the jets, but it could be dirt in the pilot jet outlet or bypass or in the float bowl where it feeds the slow jets. Are the bowls clear round the slow jet fuel pick up area? On a BS40 the slow jets are in the bowl and they get their fuel from a small cross drilling which is in the bottom of the bowl.

It's also possible that the outlets might be partially blocked. next time the rack comes off, try blowing carb cleaner through the three carbs, one at a time and compare the flow through the bypass etc from one to another.

markj · Post by **markj** » Thu Jul 02, 2009 10:44 pm

It sure seems like a carb issue. I would look at the pilot passages as well. Maybe the floats too.....but after thinking about it....if one of them were bad you'de be leaking fuel out of the carb at some point "probably". I hate problems like this. They are a freakin' nightmare to track down.

Coyote · Post by **Coyote** » Fri Jul 03, 2009 8:49 am

Floats are fine and the float level is spot on. I even had this gage made to get them perfect.

Here is the nylon 'T' on an old carburator. The straight leg is connected to the next carb via a hose. The right angle part goes nowhere, but it is barbed for a hose. Beats me.

Here it is on my bike.

tz375 · Post by **tz375** » Fri Jul 03, 2009 2:17 pm

Chris,

It's hard to tell from here, but that looks like a breather from the float bowls.

On that spare carb, if you slip off the float bowl and blow in the tubes, where does in come out? I'm guessing above the float.

Blockimg those off usually makes little difference except in some cases it makes the motor run lean because there is no atmospheric pressure pushing down on the fuel. And of course that is what pushes fuel up into the venturi.

You mentioned in an earlier post that blocking them off made it worse and that confirms that the carbs are running lean. If it's a sudden change it is most likely to be a spec of dirt that was dislodged from soewhere and has now taken up residence in a jet or drilling.

Suzukidave · Post by **Suzukidave** » Fri Jul 03, 2009 3:56 pm

I dont know if this has already been suggested and checked but is it possible the chokes ( or 1 of ) is not seating or the seat is leaking ?

Triplerocky · Post by **Triplerocky** » Sun Jul 05, 2009 9:20 am

[quote="Coyote"]OK. So let me ask you guys this. Between the center carb and the outer carbs there are a pair of nylon 'Ts'. These are on the upper most forward lines that connect the carbs together. What is their function?? I tried capping them off and it seemed to make matters even worse. Are these just simply vents??????? The fische shows nothing attached to them and they have no part number........................ Mine are pointed downward at about the 7 o'clock position.

Those "Ts" are present on my GT380 also. They are vents and probably helps to equalizes the vacuum in carbs.
They DO HAVE a vent line instead, it is the #74 in the list "HOSE, air vent", two pieces, #83, 3 pieces, are the over flow hoses from the bowls...of course they point downward.

Anyway, I dont' believe these are related to the problem that you have, the same I'm trying to resolve during the last year on my TS400

Coyote · Post by **Coyote** » Mon Jul 06, 2009 7:20 pm

OK. So I gotta ask. Could a piston ring (keystone) mounted upside down cause this behavior??? By pressuring up the crankcase instead of exhausting the pressures??

Coyote · Post by **Coyote** » Mon Jul 06, 2009 7:41 pm

Ya know, I think I may have hit the nail on the head with that last post.