Topic: newbie question: cylinders 3 & 4 not firing

[jwaych550]

Hi all,

My friend d3buttz and I are working to get my 1976 CB550 super sport four up and running but I have run into a road block with timing issues.

Cylinders 3 and 4 are not firing. I have spark and fuel... Any suggestions?

Thanks a lot,

jwaychoff

[d3buttz]

your bike sucks thats why.  

just kidding, we have it starting and running, on 1&2, and i know that the carbs are straight, my guess is its timing..........but timing is by 1&4 and 2&3 and thats where im lost. we also replaced the condenser.

[Spanner 1]

Are ya for sure the plug wires are on the right plugs? Good clean plugs?
Float bowls full on carb 3+4  and the idle/slow jets clean?

[750goes]

Coil 1 fires 1 & 4
Coil 2 firse 2 & 3

as seen from sitting on the bike coil 1 on LEFT coil2 on RIGHT

check spark at lead ends against head or other object, take off the plug caps and measure resistance,

all the same sort of plugs ??
All the same resistance caps ??
all plug leads good ??

Good battery voltage ??
plugs new or old?

[jwaych550]

Thank you,

Coil leads are correct order. Brand new battery. Plugs spark... will re-check the plugs. Although plug wires are a different make on 3 & 4. Will check back after inspection from previous owners work.

[OakBehringer]

You have spark... are you sure you have fuel and compression? Are the plugs wet with gas after running it when they're not firing?

[oldbiker]

Are you sure that plug leads 3 & 4 have NOT been switched? Remember that one coil feeds no's 1 & 4 and the other coil feeds 2 & 3.  If 3 & 4 have been interchanged, this will cause 3 & 4 to not fire.

[tomsweb1]

I had a situation where # 2 and 4 were not firing. It was extremely strange, when the plug was gounded agains the case, there was no spark, but as you pulled it away, massive blue arc across the electrode, and to the case.

The problem turned out to be that I had used resistor plugs (dr8esl, what the canadian bikes use) and resistor caps ( what the american bikes use, in conjuction with non- resistor plugs) I put d8eas in, and she purred like a dream.

Have you already tried checking the resistance on the caps and plugs? one or the other of each should have a resistance of 5,000 ohms. If your spark plug caps haven't been replaced, you may want to do that anyway, it's a relatively inexpensive insurance plan, if you will.

Hope this helps!

[HondaMan]

Where do you live, Jway? I'm in Lakewood...

[jwaych550]

Cool thanks alot. There are a lot of suggestions here that I need check and or re-check. Thanks for the advice.

Hondaman: I live on 48th and Lowell (right by Interstate 70).