TOPIC:

Ok, sorry to keep preaaching about this coil problem. Here's the deal, I'll try to explain my thoughts on it.


First I stated that I had a bad coil Cyl. 2&3....butttt, now I think I have another problem(s). I went against what I should have done, and I rode the bike while firing on 2 cylinders (1&4). Well, EVERY time I got the RPM's up- somewhere around 3500, it would kick in cylinder 3. How do I know? First, I could feel it in the power, it felt like a turbo kick in, second, I could hear it, it changed engine noise drastically (in a good way), and lastly, I can see cyl. 3's pipe getting burned (I painted it). Funny thing is, aren't cyl. 2&3 on the same coil? How could cyl. 3 be firing (periodically), but not 2 at all? Ugh, I'm lost. I haven't torn into it yet; I still need to go over all connection and clean them, grounds, etc. Also, let me state that the battery in the bike is TOAST, sat for 20 years, it's gone and we all know it.

I also get a backfire through my air pods every now and then. I'm just trying to get the bike running first, then I will do all the fine tuning. Thanks guys for the help.






ATTCH: You can see here the pipe I'm talking about...1&4 burned from running fine, 3 starting to burn becuase it only runs some times, and 2 still shiny because it's never fired.

Thanks,

-Erik

Checking all the electrical connections is the way to go.
Clean each male and female plug from the points to the coils and put a little di-electric grease on each plug befroe snapping them back together to prevent corrosion.
Also check the connections on the spark plug wires.
Pull out each plug from the cylinders, put the spark plug caps back on them, and lay the plugs on the cylinder head. Turn the bike over with the key and kill switch ON. Are you getting spark on all four?
Try this in dim lighting and you'll see the sparks quite easily.
Clean and gap the plugs if they need it as well.

Erik...what's the scoup on your CARBS bud?
Maybe it ISN'T ignition,because yes,you're right...2 and 3 ARE fireing off the same coil.(they better be wired up that way,anyway)

Have you had the carbs apart?
How long has the bike sat with fuel in the bowls?

Try to keep it short, so here goes:


My dad bought the bike brand new back in the old says...and put 6,000 miles on it. MY brother was born and my mom made him stop riding, so he parked it. Well, it sat for 21 years, and finally I (the mechanic), decided to take on the project for him. Well, I rebuilt it from the bottom up, and tore it all apart and redid it all. The carbs sat for 20 years, along with the whole motor. I tore the carbs apart and re did them all, rebuild kits and the whole bit. SInce then, they have sat maybe 3 weeks? Not too long. (I'm a Honda dirt bike mechanic).



Here's the bike when i first tore it apart (once again, keeping this short):


Here's the head and carb once I got them rebuilt:

Like I said, I haven't gotten into the whole deal of tearing into it, I was just looking for where I should start. I'll check to see if I have spark at all 4

Bad battery alone could cause the ignition problems.

Really? Didn't know that- any particular reason it would affect cyl. 2&3 rather than 1&4?

Erik,just for the sake of narrowing it down(or at least,TRYING to)...with the bike running,spray some WD40 into the carbs of the dead cylinders,and see if they come to life at all...

I'm not saying that it IS a carb issue,but what I'm suggesting is easy enough to do(if you haven't tried it already)...

Will do, thanks Sandy.





If I'm right, don't carbs 1&2 feed off the same part of the petcock, and the other half feeds 3&4? i believe so..kinda funky how 1&4 would be fine and 2&3 would be the problem one, which again tells me it's a electrical problem. I'll check it out.

Ya,you're right about the petcock,and carbs 1&2 are fed off one line,etc.(providing it's a factory set-up) but I'm looking at the whole thing as it could just be one carb in particular,internally,and nothing do do with the actual fuel SUPPLY.
Kinda like checking a SPARK PLUG,as opposed to the coil FEEDING that spark plug.

You'll get it Erik...eventually.

If it were me, I would check for spark first and maybe switch plugs for new, just because. While I was at it I would read the plugs for wet, soot, glaze or consistency. If spark were visible.....

Check compression across the 4 tubes, just because its easy. It has just been rebuilt so I doubt it is a flat cam lobe or sloppy valve seating. If pressure were reasonable.....

Carb boots? Are there any huge cracks in the carb mounting boots? If there were none.....

Fuel. I believe that they all run off of the same line from the tank. Some have one T between 2 and 3, while others have 2 T's one between 1 and 2, and another between 3 and 4. ( I have the one).

I would suspect the carb at this point. There is a fuel blockage. I would spray some starting fluid on the suspect cylinder's carb to see if it pops the cylinder to life.

How deeply did you rebuild the carbs? I threw new gaskets in mine after soaking them in carb cleaner in a coffee can. Then I did it a second time with compressed air to try to clean out the junk that I put in the first time I 'rebuilt' them.

If the electrics and compression are good, I suspect the carbs are the problem.

Try switching the coils over from right to left (switch trigger wire and plug wires). See if the problem stays on the same cylinders. If it does then that suggests that the electrics/coils are not the problem.

I would yank the carbs off again....

I will go through all the things you mentioned.


As for the carbs, they were rebuilt down to every last little nut, bolt, and oring.