carb problem?

[naughtyG]

also when draining the float bowls on the carbs, could not believe the amount of "rust particules" that came out
any ideas?

Oh yeah. Means your tank is most prolly rusty. Needs removing and treating with POR 15 or similar. Then all your fuel lines, fuel pump and carbs need a good clean, and your fuel filter replaced.

Been there, done that. Trust me, it only gets worse if you leave it. Check inside the fuel tank with a flashlight - it should be clean bare metal (or treated). Any rust = trouble for the carbs.

 

[trickster]

will do !
thanks for your support!!!!!!!!

 

[trickster]

right cleaned all carbs and put back on the bike
she fired up frist turn of the key.....
but the problem is still there
the slider does not move on one pot when revved
changed the diaphram for one that working fine
and the good slider/diaphram does not work in the "duff" carb
but the one out of the faulty carb works well in the other carb
w.t.f. going on
any ideas?
HELP NEEDED
Rick

 

[trickster]

ok
ive changed the faulty carb with one from good old ebay[had to buy all4 but got them for ?80.00] bargin!
cleaned/shotgunned them/peashot them[looknew]
stripped the carbs off the bike[maxie] kept the three good ones in place and
changed the"faulty"one with the new one[at this point i should say the carbs off ebay came from a good running bike} so i now have a set of 4 carbs ready to go back on the bike
just a sub note i can now remove and replace these carbs in my sleep and have spent that much money on carb cleaner at my local car accessory dealer he now gives my a cup of tea , and tells me am on his christmas card list........just joking
so the carbs are placed back on to "maxie"
firerd up bang the problem is still there!
i had a doubt in my head this was not going to work....because of one thing
remember the photos i put up ....you can see in one of the inlet tracks that its black as soot.. this is making me think the problem is a sticking valve
am i right thinking if the inlet valve is not closing correctly than the plug would fire blowing pass the inlet valve and up the carb. leaving the black deposits the the inlet tract and losing vaccum in the carb?

 

[trickster]

what has no one got an opinion on this
need some feedback from them who know
or are you all stumpped like me......lol:bang head:​

 

[Rhoy Carter]

Do a compression check to see what you have

 

[jfeagins]

Have you ever checked for a good, hot, consistent spark on that cylinder? Changed out the plugs?

...just thinking out loud again....

 

[deekjx]

I'm by no means an expert. I consider myself well on the novice side of this conversation. Take everything I say with a grain of salt.

There are two ideas I have.

1) Tighten up the connection to the spark plug. I read a user from another forum had a similar problem and after wasting a bunch of time discovered that the misses and backfires were caused by a poor spark plug connection.

2) Timing can be off for that cylinder. I don't know what you can do to fix this problem or verify that it is a timing problem but if the valves are not in the right position at the time of ignition/spark, I believe that it could cause this issue you are seeing.

Just out of curiosity, does it sound or act like this you tube video?

http://www.youtube.com/watch?v=mxb4euGQlP4

 

[[email protected]]

Do a compression check to see what you have

+1. Great idea if you suspect a valve problem.

Before doing that I would be checking the header temperatures. I wonder if that cylinder is not firing correctly. If so, it should be colder than the others. Check spark. Coil could be bad, cap, plug, or wire in between. Could be as simple as some corrosion or the HT lead not fully inserted into the coil.

 

[one2dmax]

Agreed. A simple plugged pilot fuel jet and carb sync could cause something like that if it was at idle all the time. I'd say no spark ever is more likely.

Sean

 

[trickster]

thank you all !
for giving more things to look at
will get back to let you know how i get on
meny thanks again
p.s. does sound like the back fire in the utube video!unk:

 

[trickster]

ok guys
changed the coil new plug,cleaned up the ht lead ends
[got a small amount of spares in my hand bag.......lol]
the problem is still there , running fantastic on 3 pots:bang head:
the video put on this thred shows the problem i have, with fuel shotting out of the main jet air bleed hole on top of the carb, when revved more fuel shots up bloody thing hit me in the eye.....good job i wear glasses......sorry but got to make light of this to stop the red cloud coming down and me reaching for the hammer !:ummm:

 

[deekjx]

ok guys
changed the coil new plug,cleaned up the ht lead ends
[got a small amount of spares in my hand bag.......lol]
the problem is still there , running fantastic on 3 pots:bang head:
the video put on this thred shows the problem i have, with fuel shotting out of the main jet air bleed hole on top of the carb, when revved more fuel shots up bloody thing hit me in the eye.....good job i wear glasses......sorry but got to make light of this to stop the red cloud coming down and me reaching for the hammer !:ummm:

I left a comment on that video asking what the owner did to correct it. I wouldn't hold my breathe for a response though. He posted that a month and a half ago so if he does respond it might even be to say its still broke.

I did find this other video that provides a run down on troubleshooting this problem. It was geared to general automotive use but should apply here as well.


http://www.youtube.com/watch?v=M92CGjpiMs4


Everyone has recommended a compression test and that is a strong next step. Based on their recommendation and the information provide in this next video, I'd say do it just to be sure you have a working engine.

http://www.youtube.com/watch?v=X_tbksFYhl4


If the engine proves to be good, I'm betting its the ignitor unit. They aren't cheap so if you have a spare that you know works you can try that or you may need to borrow one from a friends before shelling out the cheddar for one of those. You should look into vacuum leaks too according to the backfire video.

I'll let you know if I hear anything back from the guy in the previous video that has the same problem you do.

 

[vmaxinID]

Pull the plug and leave it attached, then see if she's sparking......

just a couple of revs should tell you.

 

[ninjaneer]

Pull the plug and leave it attached, then see if she's sparking......

just a couple of revs should tell you.

novice speaking: don't you need to ground the plug? i read that this needs to be done like when you are doing compression checks?

 

[maleko89]

Yes, plug needs to be grounded. I set it on top of valve cover.

 

[deekjx]

If it wasn't firing, how do we get the backfire?

 

[trickster]

deekjx
brilliant videos!!!...............thanks
if you hear from the guy in the back firing v max video......please let me know the
out come
thanks for showing interest mate
cheers
rick

 

[trickster]

If it wasn't firing, how do we get the backfire?

am with you cheers unk:

 

[deekjx]

Clearly I'm a novice at this because something has just occurred to me. I went outside and warmed my bike up for a test ride with my new leather jacket. My bike has had an intermittent problem that I don't worry because it goes away when my choke is closed. I never identified it as a backfire but after hearing it again today, I'm positive its the same thing you have on cylinder 3. It sounds exactly like what was in that backfire youtube video. To be honest I'm surprised I didn't recognize that oh so familiar sound sooner. In my case, I thought it was a vacuum leak and perhaps it still is. Take a look at this video of me syncing my carbs last year.

http://www.youtube.com/watch?v=QYWlLwxG9Do

You can't hear the noise because the sound quality of the phone sucks, the airbox was on and the faux cover was secure. I could hear it standing next to it though. If you watch the third tube, when the pressure drops out and the mercury falls back into the base, that's when the backfire is occurring in my case. I was under the impression that I could ignore a small vacuum leak if its only happening with the choke open but after looking at your photo's with all that black soot and realizing that I most likely have a backfire issue to, I can't ignore it any longer. I have to look at my carbs also! I think the engine is fine in my case since my issue doesn't happen with the choke closed. If the choke is open partially, I get the problem. If the choke is fully open, I don't believe I've heard a problem. Its more difficult to tell because the RPM's of the engine jumps up to over 3k with it fully open. When I take it apart, I'll have a better idea.

The question I have for everyone is whether or not its okay to only engaged the choke partially? It's possible that I'm just doing something I'm not supposed to. I use to do this on my old Virago all the time and never noticed a problem.