Hey Guys,
I'm in the middle of a rebuilding a CB750 1981;
This is my first ever build and It's been a whirlwind of forums, google, youtube and a local motorcycle shop to get me on track to this point.
However, I've hit a bit of a snag; the bike wont start / fire, and I wondered if any of you can help out with some advice...
There's a few issues -
- The fuel diaphragm valve doesn't appear to be working great, but in a bid to start the bike for now I bypassed this to fill the carbs with fuel and try turn the bike over. Once I know we're up and running properly I'm going to try get this sorted and ideally keep it working on the bike - I fear I'll forget to turn the Fuel Petcock OFF one day if not...
- Following the bypass, the float bowls definitely have fuel, but after turning it over a few times I checked the spark plugs (which are brand new) and they were bone dry.
- The spark plugs are sparking (tested against the engine casing), so I assume my wiring is correct to the coils and they are obviously working as they should be, right?!
- Also do the CDI / Spark Unit Boxes have a particular order when they're wired up - there doesn't seem to be an outline for that online anywhere and the boxes aren't marked by number or anything.
- I've removed the old air box and now have Pod Filters on the carbs - now I know there's usually issues on this front and people say avoid it in favour of the old Air Box, but what I'd read up on this seemed to really only affect the bike bogging down etc when riding, not actually issues with starting. Would it affect start up?
- When I previously took the carbs apart I changed the Main Jet and Idle Jet in the middle of the carbs, plus the gaskets, but nothing else. Should I have adjusted my Pilot Screw or anything now that the jets have changed?
(Overall, the carbs seemed pretty clean to me, but as a rookie I'm not sure what I'd be looking for otherwise or how to fix any issues I'd come across).
- Lastly, any other ideas on what would be preventing fuel making it to my Spark Plugs?!
Really hope you guys can help...
Thanks,
BP
I'm in the middle of a rebuilding a CB750 1981;
This is my first ever build and It's been a whirlwind of forums, google, youtube and a local motorcycle shop to get me on track to this point.
However, I've hit a bit of a snag; the bike wont start / fire, and I wondered if any of you can help out with some advice...
There's a few issues -
- The fuel diaphragm valve doesn't appear to be working great, but in a bid to start the bike for now I bypassed this to fill the carbs with fuel and try turn the bike over. Once I know we're up and running properly I'm going to try get this sorted and ideally keep it working on the bike - I fear I'll forget to turn the Fuel Petcock OFF one day if not...
- Following the bypass, the float bowls definitely have fuel, but after turning it over a few times I checked the spark plugs (which are brand new) and they were bone dry.
- The spark plugs are sparking (tested against the engine casing), so I assume my wiring is correct to the coils and they are obviously working as they should be, right?!
- Also do the CDI / Spark Unit Boxes have a particular order when they're wired up - there doesn't seem to be an outline for that online anywhere and the boxes aren't marked by number or anything.
- I've removed the old air box and now have Pod Filters on the carbs - now I know there's usually issues on this front and people say avoid it in favour of the old Air Box, but what I'd read up on this seemed to really only affect the bike bogging down etc when riding, not actually issues with starting. Would it affect start up?
- When I previously took the carbs apart I changed the Main Jet and Idle Jet in the middle of the carbs, plus the gaskets, but nothing else. Should I have adjusted my Pilot Screw or anything now that the jets have changed?
(Overall, the carbs seemed pretty clean to me, but as a rookie I'm not sure what I'd be looking for otherwise or how to fix any issues I'd come across).
- Lastly, any other ideas on what would be preventing fuel making it to my Spark Plugs?!
Really hope you guys can help...
Thanks,
BP