Motorcycle Forum banner

Ignition coil?

23K views 62 replies 9 participants last post by  MONI 
#1 ·
Bike was running real rough, idling rough, and the front cylinder was running rich, finally cut out completely one day on my way to work. My friend came and towed me after work. Looked at it the next day and it started up with both cylinders running. At first thought it was the fuel pump but not it. Noticed the ignition coil for the front was very hot to the touch while the one for the back was not after a few minutes of being off. Switched them around to check them out. Bike started right up and sounded good which was odd,,if it was the front coil and we switched, shouldn't the back cylinder being acting up? I took the bike home rode around a few days then started running rough and idling rough again. I figured it was the back acting up now. Pulled the plug for the back...looked good. Pulled plug for the front and it's running rich. Not what I expected. Anything that can make the coil for the front run hot..I don't know too much about how it all works. Thanks!
 
#28 ·
Drained the bowls so gas is getting to the carbs, still won't crank without me on the gas and when I let the throttle go, it slowly dies. Not much into carbs, can I check for a stuck float without taking carbs off? Take the bowls off without the whole unit? Could this just be the CDI unit? sigh...so much to check.
 
#29 ·
You might be able to check the float level; if you can fit a length of small clear tubing to the drain and curve it up alongside the carb, then open the drain, the fuel will rise to the level in the bowl. My Suzuki manual states what this level should be, relative to the bowl seat. I would expect it to be about 10-15mm below the seat, if your bowl seat is level. On my front carb, the bowl seat is nearly vertical, so the measurement is very different. If it is much lower, you may not be getting fuel to the pilot jet; too high, and it is flooding it.
 
#30 ·
This is weird. I did notice the tube coming from under the tank was off so put it back on..started right up and stayed running. Let it run for a few mins. turned it off. Let it sit for minute, turned the key and it came right back on and idled. While it was idling, I took that hose off but it kept running the same. What is that hose for?
 
#33 ·
If the "hose to nowhere" is coming off the carbs, it's the carb vent/overflow. The float bowls have to have a "vent" to atmosphere so the fuel level can rise/fall wothout fighting pressure/vacuum. Plugged vent tube can cause issues.

If it's coming off the tank, I have no idea. Might be wise to pick animedevildog's brain on this one. Lol.
 
#34 ·
That hose you are talking about off the carbs...I can't find it. It used to be right there, I could see it easy and I always wondered what it was for. Carbs were cleaned and I couldn't find it today, I poked around some but prolly gotta take the tank off to see it. Maybe it was tucked in somewhere
 
#35 ·
o_O Odd. Should be 2 small hoses from the carbs, the t-fitting, then hose going down to nothing. I'd make sure that whoever sirviced your carbs didn't cap something in that chain, and that the vent hose isn't wadded/kinked up in there. Those carbs gotta breathe or you'll get all sorts of drivability probs.
 
#36 ·
It could be many things - some bikes have a small vacuum line to a boost sensor, which shifts the timing with changes in vacuum. It could be a vacuum line to the fuel valve, which shuts off if no vacuum is present. I'd need a good manual to figure that out.
 
#37 ·
I haven't been following this thread all the way through, but I happen to be working on a Shadow right now in the garage with fuel issues. (2004 VT600CD) This bike has a manual petcock, and also a vacuum controlled petcock mounted separately. In the diagram for yours (http://www.westernhillshondayamaha.com/fiche_section_detail.asp), it looks like the same kind of vacuum controlled petcock unit may be attached directly behind the manual petcock. On the 600 I have here, I dismantled the vacuum controlled petcock and found a diaphram worn all the way through, making her issue oviosu and I am only waiting for parts now.

Have you checked your vacuum c*ck? On this bike there is a smallish tube running from the diaphram unit to the intake side of the carb providing the vacuum required to work the diaphram and pass the fuel on to the carb. Could that loose tube you mentioned be the vacuum tube to the vacuum operated c*ck?

Good luck,

Mike
 
#42 ·
Still haven't resolved this issue. I had to switch to reserve this morning at about 86 miles...about 20 miles too soon which had happened to me a couple of times before the front cylinder went out on me. Think I'm gonna take the ignition coils off and bring to Honda to check for me..make sure it gets done right.
 
#45 ·
I replaced my neutral switch not long after I had the bike, I kept getting a leak and found that it had been torqued to tight and it was broken ....but other than the leak I never had any other problem connected with that...
 
#46 ·
Was running ok then went across the lake. Started sounding and running funny again, having to give it too much gas to get going from a stop, felt like it wanted to stall out. It did stall once and then didn't want to start right back up. Was like that for few minutes then went back to normal. Thinking it may just be time to trade this bike in. Shop had it for about a month and only found that one switch...
 
#47 ·
I am in no way a mechanic. I have read thru this thread and for your last post...I just have to throw this in.

My Yamaha had been sitting for a couple of years and we had to clean the carbs and gas tank--even though we put Stabil in the gas when I had to park it due to my back problems.

Anyway, we bought new spark plugs shortly after I started riding again. After putting those in I had the same thing you discribed in you last post happen to me. It kept stalling out on me and then sometimes I would have to let it sit up to 1/2 hour before it would start again. I would have to give it more gas on take off for it to go but sometimes it would die anyway. It also died a few times when I was stopping at stop signs. It was very frustrating and becoming scary. We tried all kinds of things but nothing seemed to help. Hubby decided to put the old plugs back in for some reason and my bike has ran perfectly since he did. The new plugs were "supposed" to be the correct ones for my bike per the Yamaha Dealer. This is probably not your problem, but it might be so that is why I'm posting this...would you have by chance changed your spark plugs somewhere along the line of trying to figure out your problem?

I really hope you get your bike fixed soon!!! Good Luck
 
#49 ·
After all this, bike was still messing up. I had changed the ignition coils and pulse regulator also. Left me stranded last week on the way to work. Got a call from Honda today and the starter plunger had broken all the way thru. Do I want it fixed..well, yeah.
What is a starter plunger?
 
#51 ·
Me too; I could hazard some guesses, but that's a new term to me, on bikes, anyway. Our '30 Model A Ford had a starter plunger, connected to a button on the floor. You stepped on it to crank the engine.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top