spark, won't start,, cranks whne the relay is jumped

[Loubob]

1986 GS450LG

have fuel , spark but will not start

When I jump the relay it cranks like crazy.

Had the relay tested and it was good

cleaned the kill switch and start button

any ideas

Loubob

[OldVet66]

What is your voltage when cranking? You have electronic ignition and it will not start if the voltage drops below a certain level. You say the starter motor cranks like crazy when you jump it, how does it crank with the starter button? I have a suspicion cranking is dropping your voltage too low. You can test this with an automotive battery, but if it is in a running car you are going to cause damage. The auto battery should have plenty of reserve on it's own to crank the bike without a massive voltage drop. If it starts, shut it down and find the problem in the bike's electrical system before you try again while you charge the bike battery.