It was running great before I took it apart to fix the Trang- now that works but it won’t start. Backfires sometimes. Spark is present but doesn’t light up the room or snap. New condenser made for this bike acc to DrATV. Same coil as when it started. Stor puts out 6v when you kick it hard. New rectifier (the double prong one). Battery puts out 6v. Tail light, horn and blinkers work. All connections checked (6v from stator does all the way to coil.). New points. Pulse advance correctly installed. Compression 125. New spark plug x 2. Timing perfect, points gap perfect, carb soaked in cleaner x 2d, ozone boiled x2hr, blown out, jets cleaned. Carbs changed x 2. Any ideas???
1981 CT110 won’t start
- Thread starter dostrem
- Start date
Tranny was fixed. Stator puts out 6v
I’ve never had the transmission open on my 90, I don’t know what’s involved in that procedure you did. But, the fact that it is “backfiring” tells me several things; it’s getting air, it’s getting fuel, and it’s getting spark: ergo, combustion. The backfire is occurring because one of the valves is open during the combustion phase, I believe. Could you have the valve cam chain( which I think may control the valves and contacts rotor) a tooth or ? off its intended position. The spark would arrive at the wrong time and the valves would be in the incorrect position and allow combustion gases to escape either into the carb or the exhaust port??? All of this is darn near uninformed speculation on my part, but either way I will learn something from replies.
Maybe I’m misunderstanding your term “backfire”. I think if you are hearing the actual combustion noise then the combustion gases are escaping “back” into to carb and exiting through the air intake system rather than through the exhaust system where all you would hear is a normal exhaust sound? Also, are you saying it “won’t start” with starter fluid but it does backfire with the use of starter fluid? What does it do without using starter fluid, nothing in the realm of combustion, or does it combust with the resultant backfire? IMHO, if you have backfire your spark problem is the time of the arrival, that is when the valve is open at the wrong time. I think
Spark:
1, stator generates 6v ac to points and condenser
2. While points are closed, condenser charges
3. When points open, condenser send volts to coil
4. Secondary coil sends kilovolts to plug
Relevant pieces:
Stator
Points
Condenser
Coil
Spark plug wire
Plug
If all of these are ok, you’ll get a spark, right?
(Unless there’s a short somewhere)
1, stator generates 6v ac to points and condenser
2. While points are closed, condenser charges
3. When points open, condenser send volts to coil
4. Secondary coil sends kilovolts to plug
Relevant pieces:
Stator
Points
Condenser
Coil
Spark plug wire
Plug
If all of these are ok, you’ll get a spark, right?
(Unless there’s a short somewhere)
I did finally get spark. I just went thru all the wires/ not sure what the problem was. I actually have two 1981’s. The other one was essentially exactly the same issue. There I found the switch was mistakenly ground out the be wire, replaced it, got spark there too. Now I’ll try to start that one tomorrow. I’ll check out the valve timing chain on the first bike, which now has a strong spark and is no longer backfiring! This keeps you on your toes!
On my second CT110– after fixing several bad connections, changing out bad switch, changing oil, new points and plug, it started like a dream! Now I have to fix the shift arm- no threads!! Argh! I really don’t want to tear this whole thing apart! I can do it, but it’s a pain! I might just weld the arm on!