1st startup since rebuild. Bike goes bang bang

Well i have converted the bike into a cafe and i finally had the chance to try to start it up tonight.
The bike is getting spark to the plugs when i checked.
It is definitely getting fuel.

However, i get a few bangs (explosion out of exhaust) here and there and bike does not start.

My question is
1. if plugs are getting spark, have i wired up the bike correctly? coils seem to be in the right plug and bike was running before i tore it down.

I cant think of anything else to check. Im not sure if its electrical issue or mechinical.

Any inputs would be appreciated

Thank you

https://www.youtube.com/watch?v=P4k3qgYvTLQ

You say "plugs" so I'll assume you are not talking about a single.

Backfiring is caused by incorrect ignition timing. Try swapping the coils over - you might have mixed them up.

hmmmm thanks for the input.
I may have mixed up the blue and yellow wire that goes into the coils. ill swap them and see what happens

hillsy said:

You say "plugs" so I'll assume you are not talking about a single.

Backfiring is caused by incorrect ignition timing. Try swapping the coils over - you might have mixed them up.

Click to expand...

Yep, been there done that haha. Most likely the issue if you're getting SOME ignition.

always wondered about the structural integrity of a top tree thats been shaved that much. It looks cool.. but will it hold up? There are a couple of guys on here that make custom top tree's.. Mr E is one.. Cognito Moto makes them for the 750's (not sure of interchangeability).. I dunno maybe one of the more knowledgeable guys can chime in.

I agree about the coil wires though. The Wire diagrams can be annoying to sort our which cyl gets which coil.. I mean look at it.

http://www.cmsnl.com/classic-honda-fansite/honda_wiring_diagrams/CB550.jpg

You haven't mentioned anything related to setting the cam chain tension, timing or valve lash - all of which are job #1 before you bother trying to sort anything else out. Those adjustments don't change based on how well the bike is running or not, and must be done first.

Popping / backfiring could be caused by many issues - get those basic tuning steps out of the way and move on from there.

I had the same problem as you when I gt my bike back together. It seemed that the problem was the coils being connected wrong, but it turned out I had reassembled the spark advancer 180 degrees out. so If in doubt, check that too.

thanks for the help guys. it turned out my blue/yellow wire going into the coils were backwards!