Fuel Filter/ carb issue

[He Man]

the spark plugs look normal. the battery had been trying to start the bike all day, so it might actually be low battery since the spark was running directly off that. i will throw the batt on the charger and try again.

the heat is defintely coming from the upper head since its my inner theigh that burns. it was never like that before.

howie, what is it that im trying to look for if i pull the plugs and mechanically turn it over then run it till it dies? I have no idea how long it will idle for, but if it is a float bowl level problem, it would die after the float is emptied no? I took apart the bowls and they are clean as a whistle.

[He Man]

used known good plugs and battery, the spark is still this pink/piurplish color.

i was reading into the collapsing of the fuel line under excessive heat...the excessive heat caused by lean condition.... caused by not enough fuel coming from the carbs. the carbs are operating fine, so i am going backwards...

im also thinking it might be the vaccum petcock. Any way to test the device? going to remove it today. and see if autozone has a manual petock.

[He Man]

okay, tested the petcock, it works fine. Its vaccum operated. (step aside gay jokes abound!)
 
I sucked on one end and had a friend suck on the other end. it was blocked until i sucked on it. which makes sense.

the only thing i that was left to test was the fuel pump. I read somewhere that the fuel pump should have strong pulses of fuel squirting out. this thing was uhhh. very weak pulses, but it seemed like it was defintely enough gas.

The flow rate of the Ca-cycleworks fuel pump is 14Litres an hour which it looked like ( i was pumping the fuel into 1 quart glass jars and 1litre = 1 quart for all intents and purposes at this point.

so im stuck here. i ripped off each and every single line and tested them for blockage. its all clear. i did find a spring between the fuel filter to the petcock which i autoatically assumed its suppose to be there given how long it was...

any help from here on is much apperciated. the spark is strong enough to fire the bike up on the first go. Bike fire up better than my S2R1000.

[Monster750ie]

I'm not familiar with the carbed models. Do they have any sensors which measure heat and prevent ignition?

It can also be a vacume issue. On my 240 I had a cracked vacume bung. A hose was clamped on but air still found it's way in the manifold. Metal expands when hot so the crack may be amplified.

If fuels ok it's gotta be air or spark. From everything you've done doesn't look like fuels an issue. what controls ignition? Can the heat affect those parts?

[koko64]

Inlet air leaks on the rear head, or a timing issue for that cylinder (more unlikely).
Synch plugs/screws falling out and leaky manifold rubbers could make things dangerously lean. Dont want to hole a piston.

 Ive never heard of an ignition pick up working loose and advancing. I spose its possible. A faulty kgnition box?

Any pinging?

[He Man]

no pinging.

but i will check all the parts you are talking about.

actually which ones are the synch screws on a carbed bike?

the bike is over 12 years old with stock rubbers so the hoses could be a possibility

[koko64]

I mean the vacuum plugs you screw the manometer into. They are flat head type brass (usually) screws on the manifolds. They should never fall out, but who knows. I have heard of people forgetting to put them back on after a carb synch.
The fuel pump hose off the rear cylinder manifold could have perished, letting extra  air into the rear cylinder and also failing to pull hard enough on the pump causing low flow.

[Howie]

the spark plugs look normal. the battery had been trying to start the bike all day, so it might actually be low battery since the spark was running directly off that. i will throw the batt on the charger and try again.

the heat is defintely coming from the upper head since its my inner theigh that burns. it was never like that before.

howie, what is it that im trying to look for if i pull the plugs and mechanically turn it over then run it till it dies? I have no idea how long it will idle for, but if it is a float bowl level problem, it would die after the float is emptied no? I took apart the bowls and they are clean as a whistle.

Pull the plugs on the engine when cold.  Turn the engine over with a crankshaft turning tool or the rear wheel in high gear.   It should turn easy.  You know the feel since you have done your own valve adjustments and belts.  Put the plugs in.  Run the bike until it stalls.  Pull the plugs and turn the engine over again.  If the effort is notably higher you have an engine problem.  This is only to eliminate the engine as a source of your problem.  As far as the vacuum shut off goes, as a test you can just bypass it.  You do stand the risk of spilled fuel  in a tip over, but since they usually fail in the open position I don't think the risk is great.  You can even bypass the fuel pump for test purposes, just make sure the fuel level in the tank is higher than the carb inlets.  

The float bowls will still have some fuel in them, but nowhere as much as normal.  

I think you have more than one problem since you feel excessive heat from the vertical cylinder and do know what normal is.  You do have weak spark and the heat is likely a symptom of lean running or an engine problem.  Off hand I can only think of three reasons for your weak spark; bad coils (unlikely), bad resistors (spark plug caps) on the ignition wires or excessive clearance at the ignition pick ups.  Checking pick up clearance requires removing the alternator cover, so that is a last resort.  Coils should read 3.4K ohms+% from + to - and17K ohms+10% from the spark plug towers to ground.  The resistors should be 5K+10%.

Hope this helps.

I'm not familiar with the carbed models. Do they have any sensors which measure heat and prevent ignition?

Nope.

It can also be a vacume issue. On my 240 I had a cracked vacume bung. A hose was clamped on but air still found it's way in the manifold. Metal expands when hot so the crack may be amplified.

Definitely worth a check

If fuels ok it's gotta be air or spark. From everything you've done doesn't look like fuels an issue. what controls ignition? Can the heat affect those parts?

[Howie]

I mean the vacuum plugs you screw the manometer into. They are flat head type brass (usually) screws on the manifolds. They should never fall out, but who knows. I have heard of people forgetting to put them back on after a carb synch.
The fuel pump hose off the rear cylinder manifold could have perished, letting extra  air into the rear cylinder and also failing to pull hard enough on the pump causing low flow.

 

[Monster750ie]

Any progress he man?

[He Man]

nope, i have midterms this week so im stressing out over studying instead.


I went searching for a rebuild kit. the Diaphragm on the fuel pump is looking thin in some areas and flat. While im in there i was thinking about rebuilding it or replacing it.


suggestions? Pick up a rectangular one from CA-cycleworks or rebuild the pentagon one?

i found this rebuild kit, which is kind of misleading cause its a pic of a rectangular one...
http://www.bikebandit.com/mikuni-fuel-pump-rebuild-kit-for-pentagon-pumps

[Howie]

nope, i have midterms this week so im stressing out over studying instead.


I went searching for a rebuild kit. the Diaphragm on the fuel pump is looking thin in some areas and flat. While im in there i was thinking about rebuilding it or replacing it.


suggestions? Pick up a rectangular one from CA-cycleworks or rebuild the pentagon one?

i found this rebuild kit, which is kind of misleading cause its a pic of a rectangular one...
http://www.bikebandit.com/mikuni-fuel-pump-rebuild-kit-for-pentagon-pumps

If it is a genuine Mikuni kit go for it.  Also try Sudco.

[koko64]

I went the Cycleworks pump and got two for a spare at the great price.  They are smaller. Painted mine black to blend in a little better.

[He Man]

are there advantages to the square pump? because the genuine rebuild kit ($15 bucks) is cheaper.

that is assuming hte rebuild kit was as they stated it. (it says brand : Mikuni)

[koko64]

Just size from what I can tell. Also lighter!