cylinder #1 , 2 , 3 cold ?!

classic Classic list List threaded Threaded
5 messages Options
Reply | Threaded
Open this post in threaded view
|

cylinder #1 , 2 , 3 cold ?!

jamthebamm
Well when it happened , I thought it must be the carbs so I cleaned the shit outa them . I put the carbs back on the bike yesterday but still cold engine  , same shit . when I started the bike I could smell gas is spraying inside the engine but no fire , I checked the spark plugs they were all wet except #4 . the problem started showing up when I changed my old regulator with a new one ( Rick's ) almost like a day or two after replacing it . when I changed the regulator,  very first thing I did was checking the battery voltage , it was 15.6 at 3000 rpm which is too much , second time I turned the bike on and checked , it was back to normal  14.5 v but the cylinders went cold one by one almost a day after . I changed the spark plug wires with KNG and switched the coils but still same thing . My mechanic friend told me it might be your spark units , that some how the new regulator fried them and that's how you got too much voltage in the first start .
I also checked the pulse generator and it was covered with sticky brown stuff which I think it was oil ( mistakenly I added too much oil to the engine last month and noticed oil is leaking out of the engine , I drained the oil back to normal and resolved the problem )
well I was wondering if the problem is comin from spark unites before I spend some money on them .
Assembly of a Japanese bicycle require great peace of mind.
" Zen and the Art of Motorcycle "
1981 Honda cb750 C
Reply | Threaded
Open this post in threaded view
|

Re: cylinder #1 , 2 , 3 cold ?!

TOOLS1
Administrator
Have you check to see if you are getting spark? Very odd that 3 cylinders would go dead because of ignition. If the high voltage did fry the spark units, you would have 2, or 4 dead cylinders, not 3.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
Reply | Threaded
Open this post in threaded view
|

Re: cylinder #1 , 2 , 3 cold ?!

jamthebamm
yes I checked the sparks and they seemed to be normal ?!?! but still no fire inside the cylinders . I have 2 different batteries  , I run the bike on both of them , with my acid battery I get back fire 1 outa 10 from the running cylinder (#4) but with my lithium battery 6 outa 10  , I thought it might  relatively indicate some issue .
when I cleaned the crabs I also replaced  the intake boots with new ones . is it possible to get cold engine be cause of leaking boots ?
Assembly of a Japanese bicycle require great peace of mind.
" Zen and the Art of Motorcycle "
1981 Honda cb750 C
Reply | Threaded
Open this post in threaded view
|

Re: cylinder #1 , 2 , 3 cold ?!

TOOLS1
Administrator
"is it possible to get cold engine be cause of leaking boots ?" Not really, it should just run crappy, but run. Since you have spark outside the cylinder, you should have it inside the cylinder, and since you mention backfire, this indicates that you have your plug wires switched. Battery's should not have any effect on running, as long as they have 12 volts.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
Reply | Threaded
Open this post in threaded view
|

Re: cylinder #1 , 2 , 3 cold ?!

shinyribs
Administrator
The choke plates on the DOHC carbs are kinda weird. Just because you pull the cable to activate the choke doesn't mean the butteryflies actually moved. They are attached by this weird lil spring loaded dealio. You can see the shaft that the choke butterflies are attached to running in between the carbs. There is one between carbs 1&2 and another between 3&4. Put your finger on those and make sure they are actually rotating when you move the cable back and forth.


I recently mounted a set of carbs on my '80 and they ran great. Next day,no start. I didnt't realize it was because my choke was acting this way (see you can't really see the little buggers) until i removed my breathers to have a look at what was up.

You may be able to open the access door on your airbox and see in there good enough to see whats up.

With out a choke a cold bike just don't want to start. I could pump and pump and pump the throttle to work the accel. pump (and it was shooting fuel just fine) but it never would start. It would just burp and spit occasionally. Once I saw the sticking choke plate deal I closed them by hand it she fired up and purred fine. It's worth a look.