One pipe not getting hot...

[skubasteve!]

Hey guys, Im a total noob so sorry if this should be in the carb/fuel thread.

Been having troubles with the bike lately, had the carbs cleaned out a second time by a mechanic (free) rode great. I hadnt rode the bike in a few weeks. I fired it up today because I was going to go for a ride but I noticed that cylinder #1 (I believe) the farthest to the left when sitting on the bike, was not getting nearly as hot as quickly as the other three. The bike fired up fine and sounded to be running fine, but I did notice a slight hiss, or air leak sound.. not sure if thats a concern.

Anyways, what kind of problem do you think Im looking at? Again, Im a total noob so Im explaining this as best I can.

Thanks for your time.

Steve

 

[Billy Ricks]

Switch the wires between 1 and 4 and see if the problem moves to the other cylinder. They both fire at the same time so they can go on either side with no harm done. Mixture or synch could be off on that cylinder as well.

 

[tom203]

Hey guys, Im a total noob so sorry if this should be in the carb/fuel thread.

Been having troubles with the bike lately, had the carbs cleaned out a second time by a mechanic (free) rode great. The bike fired up fine and sounded to be running fine, but I did notice a slight hiss, or air leak sound.. not sure if thats a concern.

Steve

Did the vacuum hose from petcock to carbs get left off ?( Assuming you have one.) This would hiss nicely!

 

[Billy Ricks]

Did the vacuum hose from petcock to carbs get left off ?( Assuming you have one.) This would hiss nicely!

Good point, I missed the hiss. If vacuum comes of #1 that could be the problem.

 

[skubasteve!]

Thank you for the responses.

I FINALLY had a chance to go and look at it today, looked like the hoses were connected to and from the petcock. I figured maybe it had a bad day last time so I prayed that when I fired it up all would be working properly.

Well, I was wrong, now not only is cylinder 1 not firing, cylinder two is not as well. Am I in more trouble than I was before? The exhaust on the left side was coming out cold, while the right was hot. Neither of the two left pipes coming from the motor were not getting hot...

Please tell me this is possibly an easy fix, or something stupid? Ever since I got this bike nothing has gone right! I know its probably partially my fault for being a complete noob.

Thanks for any responses if anyone has time to help me out!

Steve

 

[mike_of_bbg]

Well, your bike is a 79 so should have VM carbs with the petcock connecting to #3, right? And #3 is not a problem cylinder?

Are you feeling the pipes only at idle? What if you rev it up a bit?

Are your wires swapped on cyls 1 & 2?

 

[skubasteve!]

Well, your bike is a 79 so should have VM carbs with the petcock connecting to #3, right? And #3 is not a problem cylinder?

Are you feeling the pipes only at idle? What if you rev it up a bit?

Are your wires swapped on cyls 1 & 2?

Not sure of the carb model, it is a 78 though, not a 79 not sure if thats the same carbs.

Yes the petcock connects to #3 and #3 cylinder and #4 cylinders are the two that are running.

The #1 and #2 pipes at idle are cold, with the exhaust being cold as well. Even if I rev it up a little bit, they were still pretty cold, maybe a hint of warmth. When I gave it some throttle it didnt sound right (obviously), again I am a complete noob so please try and work with my horrible explanations.

 

[bobthebiker88]

cloggged pilot jets. remove carbs disassemble and clean until air flows through and light is clearly visible through each jet. also clear the orifices that associate with said jets.

 

[BadBillyB]

Hey Steve, try swapping the spark plugs from one side to the other and see if the problem moves. Might just have a couple fouled plugs....Billy

 

[skubasteve!]

I was afraid of that answer. This will be the third time the carbs have been cleaned on this bike since its been in my possession. I have put less than 200 miles on it I have had my mechanic do it the last two times, second being free. He thought there may have been some tiny debris in the tank since it sat for so long, so he flushed it out and added a fuel filter, but I guess that didnt really work since they are messed up again.

I guess its something I will have to learn to do myself if its going to be needing it this often. Im just scared to do it, I have very little mechanical experience.. I know there are write ups on here and I looked through them, however it just looks like lots of things for me to screw up. I guess itll be my winter project..

Anything else I should check before having to rip the carbs apart, could it actually be something simple for once?

 

[skubasteve!]

Hey Steve, try swapping the spark plugs from one side to the other and see if the problem moves. Might just have a couple fouled plugs....Billy

Thank you for your response, I will try this! This is one of the few things I can actually do!

 

[bobthebiker88]

I can almost assure you its carbs if the bke sits for any length of time over two weeks with fuel in the carbs. in my experience, this ethanol crap they call fuel goes bad and gums up jets VERY FAST.

What I suggest, is if you're going to let it sit for any period of time, fuel stabilizer, nd if possible, to drain the fuel from the carbs.

 

[RipRoaringFun]

If it's been on the sidestand and you have full carbs, maybe you have fuel dripping into the 2 lowest cylinders.

Check the EASY thing first. Remove the 2 left spark plugs and see if they look wet/black/fouled. Normally the plugs should look light tan.

You may also have a marginal battery. The fact that after sitting for a longer time the problem 'spread' from cylinder #1 to another cylinder makes me instantly think "battery needs filled and trickle-charged."

I would do the following:
1) trickle charge the battery for a couple-three hours after you put (only!) distilled water to top off each cell in the battery. Don't forget to leave the battery cell's yellow caps OFF when trickle charging. I put a paper towel over the battery -- it still lets the battery's cells vent to air as they charge and catches any vapor/moisture bubbling out of each cell

2) put in 4 new spark plugs

3) leave the bike on the center stand when parked

4) fire it up after battery charge and 4 new plugs.

If the bike fires *and* those two original plugs you pulled from #1 and #2 cylinder looked black/wet, you have a clue. You could obviously do (1) and (2) one at a time and try to get the bike going after changing only one thing and that might tell you more.

I just gave the steps together in case you need the bike as a rider.
If your petcock on the gas tank has malfunctioned, it may be allowing gas to keep flowing to the carbs even with the engine off. It's not supposed to do that -- even with the petcock in the 'on' position, the vacuum from the motor is required to pull open a diaphragm in the petcock to get gas flowing to the carbs.

The following assumes your petcock is the standard 'diaphragm' type that comes stock on most bikes.

The petcock is *supposed* to only come on when the engine starts -- the way it works is -- there is a hose connected from one of the carbs (not sure which one on your model) to the petcock -- the vacuum in that carb travels to the petcock via that hose and pulls open a diaphragm inside the petcock, allowing fuel to flow.

Easy to check if the petcock is bad, allowing fuel to flow all the time (and maybe flooding your #1 cylinder when you park the bike and it's leaned over a bit on the sidestand) -- remove all hoses connected to the petcock and turn the gas to 'on' -- no gas should come out UNLESS the petcock is bad. If it is bad, gas will flow as soon as you turn the petcock to 'On.' Normally the petcock needs 2 things to allow gas to flow to the carbs:

1) the petcock is switched to 'on' or 'reserve'
2) and the vacuum line from the carb is attached, so when the engine turns over, the suction in that carb from the engine pulls open the diaphragm in the petcock. Then and only then should gas flow.

If your petcock is bad, then simply turn it to 'Off' when you park the bike -- then get a new diaphragm or a new petcock.

Normally when the fuel is flowing continually from the petcock to the carb, the excess flows out the carb drain tube -- unless it is clogged from gunk -- which is not uncommon. Then the carb fills up with gas and can flow into your #1 cylinder when the bike's on its sidestand. Drain the oil if you suspect this, and if the oil has a gas smell -- fix the petcock and carb overlow problem also.

NOTE: the symptoms you describe can come from other sources, but check the easy stuff first, plugs and battery.

 

[skubasteve!]

Thank you everyone for your responses. It is truly appreciated from a novice like myself. I will check the plugs and battery. I do leave the bike on its sidestand, I didnt know that was a problem... I guess Ill have to train myself to get it up on the center stand since Im not very good at it.

Thank you all very much for your help and kindness.

If it's been on the sidestand and you have full carbs, maybe you have fuel dripping into the 2 lowest cylinders.

Check the EASY thing first. Remove the 2 left spark plugs and see if they look wet/black/fouled. Normally the plugs should look light tan.

You may also have a marginal battery. The fact that after sitting for a longer time the problem 'spread' from cylinder #1 to another cylinder makes me instantly think "battery needs filled and trickle-charged."

I would do the following:
1) trickle charge the battery for a couple-three hours after you put (only!) distilled water to top off each cell in the battery. Don't forget to leave the battery cell's yellow caps OFF when trickle charging. I put a paper towel over the battery -- it still lets the battery's cells vent to air as they charge and catches any vapor/moisture bubbling out of each cell

2) put in 4 new spark plugs

3) leave the bike on the center stand when parked

4) fire it up after battery charge and 4 new plugs.

If the bike fires *and* those two original plugs you pulled from #1 and #2 cylinder looked black/wet, you have a clue. You could obviously do (1) and (2) one at a time and try to get the bike going after changing only one thing and that might tell you more.

I just gave the steps together in case you need the bike as a rider.
If your petcock on the gas tank has malfunctioned, it may be allowing gas to keep flowing to the carbs even with the engine off. It's not supposed to do that -- even with the petcock in the 'on' position, the vacuum from the motor is required to pull open a diaphragm in the petcock to get gas flowing to the carbs.

The following assumes your petcock is the standard 'diaphragm' type that comes stock on most bikes.

The petcock is *supposed* to only come on when the engine starts -- the way it works is -- there is a hose connected from one of the carbs (not sure which one on your model) to the petcock -- the vacuum in that carb travels to the petcock via that hose and pulls open a diaphragm inside the petcock, allowing fuel to flow.

Easy to check if the petcock is bad, allowing fuel to flow all the time (and maybe flooding your #1 cylinder when you park the bike and it's leaned over a bit on the sidestand) -- remove all hoses connected to the petcock and turn the gas to 'on' -- no gas should come out UNLESS the petcock is bad. If it is bad, gas will flow as soon as you turn the petcock to 'On.' Normally the petcock needs 2 things to allow gas to flow to the carbs:

1) the petcock is switched to 'on' or 'reserve'
2) and the vacuum line from the carb is attached, so when the engine turns over, the suction in that carb from the engine pulls open the diaphragm in the petcock. Then and only then should gas flow.

If your petcock is bad, then simply turn it to 'Off' when you park the bike -- then get a new diaphragm or a new petcock.

Normally when the fuel is flowing continually from the petcock to the carb, the excess flows out the carb drain tube -- unless it is clogged from gunk -- which is not uncommon. Then the carb fills up with gas and can flow into your #1 cylinder when the bike's on its sidestand. Drain the oil if you suspect this, and if the oil has a gas smell -- fix the petcock and carb overlow problem also.

NOTE: the symptoms you describe can come from other sources, but check the easy stuff first, plugs and battery.

 

[Big T]

It does sound as if your carbs are clogged up again

This is probably from debris in the gas tank. Get one of those mirros on a handle from the auto parts store and look inside - you could have a rust issue, be sure and check the inside top of the tank

As asked above, are you sure you didn't swap the plug wires on #1 and #2?

Once cleaned, you carbs should go 10+ years unless tha bike sits a lot.

Also, did you check the spark plugs to see if they're fouled?

BTW, there is no "Off" setting on your petcock