Topic: need help 1980 cb 650

[cmkemp195]

i just got a 1980 cb 650 i have been driving it for about a month all of a sudden on my way hom last friday the bike strated running ruff .Every time i give it gas it stalls out but it idels fine so i changed gas line thinking it was starving for gas. well the line was old and crappie.did that it started great motor was doing the same thing.so i checkd the pipes on bike only 2 were hot so i thought weel coils.but looking at it the 2 pipes that were cold were the outside pipe onleft and the inside pipe on right.and now i dont think its coils anyone have any ideas the plugs are all good i pulled plug out of the out of the outside left it was good it had a very low puple spark when i tested it on side of motor..please help 

[trueblue]

Check your charging system is working properly, if your battery voltage is low you will have weak spark which will cause breaking down as you accelerate.

[BrianScb650c]

but looking at it the 2 pipes that were cold were the outside pipe onleft and the inside pipe on right.and now i dont think its coils

Why would this make you think it's not the coil? The left(shift lever side) coil should feed the #1 and #3 cylinder, and the right(brake side) coil should feed the #2 and #4 cylinders. So if you aren't firing on #1(far left) and #3(inside right) it would make sense that there is a problem with that coil or the way it is connected.

[trueblue]

but looking at it the 2 pipes that were cold were the outside pipe onleft and the inside pipe on right.and now i dont think its coils

Why would this make you think it's not the coil? The left(shift lever side) coil should feed the #1 and #3 cylinder, and the right(brake side) coil should feed the #2 and #4 cylinders. So if you aren't firing on #1(far left) and #3(inside right) it would make sense that there is a problem with that coil or the way it is connected.

Not quite mate, the coils feed 1&4 and 2&3.   

[BrianScb650c]

but looking at it the 2 pipes that were cold were the outside pipe onleft and the inside pipe on right.and now i dont think its coils

Why would this make you think it's not the coil? The left(shift lever side) coil should feed the #1 and #3 cylinder, and the right(brake side) coil should feed the #2 and #4 cylinders. So if you aren't firing on #1(far left) and #3(inside right) it would make sense that there is a problem with that coil or the way it is connected.

Not quite mate, the coils feed 1&4 and 2&3.   

Is that how it is? My bad.. guess I remember wrong from swapping my plug wires.

Edit* yep I was wrong. That's what I get for responding right after waking up.

[curemode2002]

+1 on the charge of the battery if it is not high enough you can get this behavior as the coil is not fully powered when it is triggered.

Also check your coils for cracks this can cause some spark strength issues as well especially if they crack by just one of the outputs.

With the Stock coils you can also disconnect the plug wires cut off a half inch or so and reseat them this will help if the ends are corroded just make sure you hit it with some dielectric grease.

[cmkemp195]

thanks for all the replys i swapped a plug from a cylinder that was running and after about 2 mins they started to fire and run right still have a hesataion took it down the road and now couple of the carb bowls are starting to leak you guys think they need to be cleaned i think the bike sat for a while before i got it any ideas would be great thanks guys

[curemode2002]

3000 mile tune up, clean the carbs and keep a close eye on the charging system