I have a 1973 TM250 Suzuki. It has strong spark and I believe it's getting gas, but I can't get it to fire up. I choked it, primed it and kicked it until the cows came home, but it won't fire up. NOTE: One time after priming with carb cleaner it fired and ran for about 2 seconds. I cleaned the carb and the plug is brand new. Is there something else I need to clean up for it to run?
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Old Cycle Won't Start
- Thread starter yeehaw1960
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How do you know the spark is strong enough? Simply viewing the spark plug firing is not good enough.
It does not take a good ignition to arc 20 thou. Your spark should arc about 1/4 inch if it is magneto, points/condenser. If it is electronic, it should do better than that.
Regardless of spark, you said the bike ran on carb cleaner. This tells me the bike is not getting gas. Did you pull off the fuel hose at the carb to make sure gas is there? If no gas, clean tank and fuel valve/filter. If you have gas at the carb then I suspect the needle/seat assembly is gummed up. Did you remove the float and needle? Often, the pin attaching the float assembly is seized - be careful not to break anything! I would try blowing out the seat with low air pressure before removing it. These things often seize too.
Starting fluid works good for removing gum and green.
Good luck.
It does not take a good ignition to arc 20 thou. Your spark should arc about 1/4 inch if it is magneto, points/condenser. If it is electronic, it should do better than that.
Regardless of spark, you said the bike ran on carb cleaner. This tells me the bike is not getting gas. Did you pull off the fuel hose at the carb to make sure gas is there? If no gas, clean tank and fuel valve/filter. If you have gas at the carb then I suspect the needle/seat assembly is gummed up. Did you remove the float and needle? Often, the pin attaching the float assembly is seized - be careful not to break anything! I would try blowing out the seat with low air pressure before removing it. These things often seize too.
Starting fluid works good for removing gum and green.
Good luck.
Clean the carb again.
BTDT.
You may have missed a jet some where.
Most spray carb cleaners are pretty weak, it may take
a fine wire to insure the jet(s) are open.
A strand of wire from a auto wire is copper and should hurt the jet if you are gentle.
A cautious use of starting fluid may help it get going; don't overdo.
BTDT.
You may have missed a jet some where.
Most spray carb cleaners are pretty weak, it may take
a fine wire to insure the jet(s) are open.
A strand of wire from a auto wire is copper and should hurt the jet if you are gentle.
A cautious use of starting fluid may help it get going; don't overdo.
i awalys have good l;uck pullstarting stubborn bikes. maybe give that a shot.
Rings could be stuck;= low compression.
Or crank seals.....
Take the carb out and do like dwendt suggested. I would even take the jets out and make certain they are not varnished up. Wait...they ARE varnished up. The orifices need to not only be clear, but cleaned of varnish as well.
You won't hurt anything, just be gentle and put it back together like it was. You won't need to completely dissasemble the carb, just take the jets out, clean em, and put them back in. If you can unscrew it, it is probably a jet.(under float bowl cover)
Also check to make sure the float is funtioning properly. It must move freely, and needs to be set properly. You will need a manual for that.
Now, no matter what you feel about the one you have, change the plug. They are cheap, and bad ones can fool you.
Also, there is probably an air screw on the side of the carb. Make certain this is not screwed in tight and choking the carb for air. Most of them are set proper at about 1-2 full turns out from tight closed.
This may have been the last thing that the former guy messed with, and it may simply be starved for air.
You may want to make sure there are no rats nests in the air filter as well. Stranger things have happened.
You won't hurt anything, just be gentle and put it back together like it was. You won't need to completely dissasemble the carb, just take the jets out, clean em, and put them back in. If you can unscrew it, it is probably a jet.(under float bowl cover)
Also check to make sure the float is funtioning properly. It must move freely, and needs to be set properly. You will need a manual for that.
Now, no matter what you feel about the one you have, change the plug. They are cheap, and bad ones can fool you.
Also, there is probably an air screw on the side of the carb. Make certain this is not screwed in tight and choking the carb for air. Most of them are set proper at about 1-2 full turns out from tight closed.
This may have been the last thing that the former guy messed with, and it may simply be starved for air.
You may want to make sure there are no rats nests in the air filter as well. Stranger things have happened.
Depending on what cycles you are familiar with, remember that on Japanese carbs. the idle mixture screw is an AIR jet, out=lean.
The wire from the wire type garbage ties work Great for cleaning jets. Just peal off the paper to the wire and its perfect.
yeehaw1960
Thread starter
Sorry...I forgot I posted this question. I've had the carburetor completely disassembled. It's very clean throughout. The engine doesn't offer must resistance when I kick it. I'm betting the rings are worn out. I'll have my son-in-law pull me around with the truck tomorrow and let you know.
Did you check the screen in the fuel filter or fuel petcock? Many of those clog with old fuel.
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