ok here it is i riding a friends 99 f4 parked it in my yard took a nap got back out and it wouldnt start now he told me he had a problem before but it was his ignition switch which he has taken down but now we change the switch the bike is just rolling over wouldnt start we check to see if it was firing but it wasnt then we hook up the old switch kept on trying and every now an again it would give a lil spark then it stop firing all together what else could be the problem we check to make sure it was getting gas we even bi-pass the fuel pump but still nothin happen it is just not firing we are just out of options it didnt give any indications while riding because i rode home normal shut the bike down and that was it just wouldnt start again, any help will be gladly appreciated.

 

the plugs could have been fouled out some how...try new plugs man!

 

Regulator and your grounds. May be that your battery isn't grounding very well or the regulator is going.

Andrew

 

Regulator and your grounds. May be that your battery isn't grounding very well.

Andrew

 

Don't know if you figured it out yet, but let me know if you do. Sounds like the same thing mine does. I haven't really looked into it but I just slap the rear plastic, right side, where the battery is and problem solved...at least for a while. It usually starts acting up again after a few hard landings.