Why wont my motorcycle start? HELP?

Question

I have a 1980 honda twinstar cm200. It's stuck in a gas station parking lot because it died, I dont know why! It will start up but wont idle with out the choke. Unless I start riding it but then it just dies again after a while. It's leaking from a tube under the bike I'm not sure what it's called I think maybe breather tube though not for the battery. Also it makes a scary clunking sound when I shift into first gear. I just had the carburetor cleaned well, and the battery replaced. Dose anyone have an idea of what could be going on? I need to figure it out soon, I'm worried it will get towed or worse stolen! Any help would be great. Thank you!

Answer 1

If I understand you correctly, the bike starts and dies...the fact that the bike starts would indicate that you have spark, fule and air. (without any one of the three the bike wouldn't start at all).

First thing I would look at is the fuel delivery system, check to see if the fuel filter is in some way obstructed and not allowing enough fuel through to maintain a running condition. Then the fuel pump to make sure you have pressure. The fact that you just had the carbs "cleaned" may suggest that something was not put back together properly or that something during the cleaning process lodged in one of the jets proventing fuel from flowing properly....REALLY GOOD PLACE TO START

Next check spark, there are several ways of doing this, the best is to pull one wire, hold it close to a known ground and have someone hit the starter, you should see a good blue spark. If you don't, have a strong spark, check your coil and/or stater. (not starter) a breakdown in the engine electrics can cause the bike to shut down (check your battery as well, a weak battery could also shut down a bike)

Lastly check your air supply. Air filters are often neglected. Check for vacuum leaks.

There are very few reasons any internal combustion engine would present with the problem you discribe. Feel free to contact me if you have any more questions. I'll see what I can do to help

Answer 2

You say you just had carb work. There is the possibility that the leaking tube is gas leaking out from the carb bowl overflow. This would mean either that the float valve was stuck open somehow or that the bowl drain screw isn't secure.

Sometimes tapping the carb bowl will release the float valve. And you can check the drain screw to see if it is loose.

Without more information (such as WHAT is leaking from the tube...gas?...oil?) it is hard to diagnose the problem.

A vacuum leak could cause the poor idling and running issue. The clunking sound could be a clutch or transmission problem. You should try and determine where the sound is coming from.

After you get the bike home, get a service manual (should be cheap for that old a bike) and start checking the bike over good.

Answer 3

You need three things to run an engine: carburetion (fuel), compression, and combustion (spark). The fact that the bike kind of runs, means you have at least spark. The "choke" is actually an enrichener system on the Twinstar, so it sounds like the engine is starving for fuel if it only runs with the choke on. Is the tube an overflow from the newly cleaned carb, perhaps? Was it sitting for a long time? Is there oil in the transmission (the "scary clunk")? There seems to be more than one problem going on. Have someone who knows what they are doing take a look.

Answer 4

Well, if it's "clicking", then it means it IS electrical, because the engine starter isn't getting the amperage it needs to start. You need to take the battery cables off , clean them thoroughly of any white powder residue ( battery acid solidified ), and scuff them down to a silver sheen so they'll make good electrical contact. Check your cable connections all the way thru, to the starter, etc. Look for loose bolts/nuts, corrosion, etc. You may think you're charging the battery, but if there is white powder all over the connections, you may not be charging it effectively. You'd need a voltmeter to check not just the cable you attach the charger to, but the actual terminal in the center, to see if the voltage is getting TO the battery. Basically, just clean both battery terminal ends, cable and battery, and retighten, then recharge. Are you using a small trickle-charger, or a larger, more professional one? If a trickle, it'll take a long while to charge it up enough, maybe 6-8 hours. If you're leaving it connected, and you have a short circuit, you won't be effectively charging it, either. I've jump-started my motorcycles with automobiles ( if you have a 12-volt system, NOT a 6-volt! Don't try it if you have a 6-volt, it'll damage it ). Anyway, make sure all your connections are clean and shiny, and you have an adequate charger, or alot of patience.

Answer 5

Look in the gas tank with a flash light.
If you see any junk floating around, or rust on the walls of the tank, the carbs will have to be re-cleaned.
If there is rust, it clogged up the slow speed jets and is preventing the float needles from turning off the gas to the float bowls, causing them to over flow.

Answer 6

I studied automotive for about a month (2 hrs a day MWF). And in our Practical Exam the problem is the gap of the spark plugs. Make sure they are gapped right.

Answer 7

Have you checked the oil level? Sounds like your oil is making a break for it through the engine breather pipe.

Answer 8

if it wont idle without the choke, reach under the carbs and find a knob. That's your idle speed adjustment. play with it a bit until you find a good idle speed

Answer 9

Try new plugs, go to your local parts dept, and ask the people there, they are usually really good with figuring things out. Good Luck!

Answer 10

Try gas , Just $ 3.00 a gallon
Sorry , no help on the mechanic thing