You have a dry plug going in, try fire up and keep pulling throttle several times and pull plug, it should be wet smell petrol.

Seems like I am jumping all over the place. Next process is gas

I will give that a try hooking up tank But thinking about this the other plug was dry but will try again when I was cranking

When I took the spark plug out I had very good compression I can feel it with my thumb and also I can hear it

I have $100 manual from yamaha for this bike it doesn’t tell you anything about the CDI how to check it to make sure I’m getting good enough spark it’s a shame

Well, a thump and hearing dont tell you anything, use a compression instrument gauge.

Thanks. I am aware of that however at least I know that the piston is moving for now.

Take the plug out, dump about 10 ml (2 teaspoons worth) of fuel straight down the plug hole, replace the plug and kick it over. If it fires - even for a couple of seconds - you've got a spark. If you've got a spark then it's the carb.

My best bet is this fuel. This may be a case where youur fuel system is partially blocked. Typically this happens in the carburettor's fuel intake or the lowest part of the fuel line relative to the height of the carburettor's fuel intake . What happens is that the partial blockage allows for fuel to seep past the partial blockage when the engine is shut off for a while (or under very little load) - creating a "reserve" that will last for seconds or minutes, all depending.


Unleaded fuel has a short shelf life, and more so under certain conditions than others, and more so for certain types if unleaded than others. As we are talking a carbureted bike, it is an older bike which may have seen many periods with old gas in the fuel system. Combine that with a half filled tank (air) and a bike left outside or other unstable climate (condensation, etc), and the negative effects increase. Combine that with debris in an old tank, and the fuel system can seriously gunk up.

The good thing is that the most difficult gunk settles low and doesn't cause havoc throughout your system - only in one or a few very concentrated areas - where gunk can gravitate to the bottom. I had one very bad case where I had left a scooter for two years untouched, under terrible conditions. The gunk had turned into a plug as hard as plastic inside the lower part of the fuel line. After extracting the plug using a regular screw, the problem was solved.

Clean your carburettor thoroughly and check that the float actually floats freely (sometimes the plastic can crack and fuel seep inside, and other issues). Check for gunk in the lower end of the fuel line, clean mechanically and flush the line. Using compressed air or liquid through the line (both ways) is a good idea, if not too inconvenient. Since you are already into this mess, it is a great opportunity to replace the fuel line anyways - maybe into one with metal hose sleeve to prevent vapor lock?

Great thanks. I ordered up a coil and a new spark plug adapter just in case. I just want to be careful of gaskets cause parts are hard to get cause of parts supply and shipping. Will fill you in on progress

The best way or easy way to get the carb out. I had it out about 8 yrs ago. Don’t remember the struggle but will try the spark first, what I will try is cut the spark plug wire back then screw the adapter back on and give it a try. Wheelie you might be right cause I did leave it outside covered in the cold until I put it in the trailer, it did start up for me to put it the trailer but it stalled out after 2 minutes on choke but it was cold out that day so I tried to start it back up and the bike just started to crank so filled the bike up with gas and stabilizer and away she went. The is a good runner never had any problems with her basically all original except for the carb rebuild and intakes.

Its fast and easy pulling carb, loosen all clamps, loosen screw battery case, 4 screws on top airfiltercase,remove cover over airfilter, rubber moutning in back, then just pull carb out towards stand side, need correct angle, the airfilter case must be pulled back when doing this. Its rubber gasket in bottom carb for reuse.

Tested the pick up coil tests good. I put some gas in the cylinder to check for spark nothing. Now I did cut the spark plug wire back and I installed the spark plug adapter back on. Before that I did on all out it test good. But still don’t get a good spark on the plug. I did ohm neg of the coil to the spark plug adapter no reading but when I do them individual nothing. What I am going to do is get is a spark plug tester that I put on the plug and the wire to see if there is a good spark. Should I check the valves next. Any help would be appreciated. Thanks x again

Is your lead/cable to the plug good? They can fail.

I ohm it out from the neg side of the coil ( which is where the orange wire goes to ) to the cable, I did take the spark plug adapter off cause the manual said so, and ohm out good. The next try is putting a spark plug tester that plugs into the plug and then into the adapter and we will see what happens. Now when I tested the coil I left it in the bike and took off the orange and black wire and ohm between the + and ~ to see the readings all good