Author Topic: Cb750a Issue HELP  (Read 212 times)

0 Members and 1 Guest are viewing this topic.

Offline 1977cb750A

  • Full Member
  • *
  • Posts: 2
Cb750a Issue HELP
« on: September 30, 2020, 12:32:44 pm »
Hey everybody

I am having an issue on my 77 CB750a. I can ride it about a mile to a mile and a half before it drop from 60mph to 40mph and die or sometimes it will keep going 30mph for a mile or two then it dies. Awhile after it dies it will start and do the same thing again a mile down the road. We found an issue with the reglator and fixed it its charging now 13v. We replaced the sparks plugs and cleaned the fuel bowls. It did the samething again today 60mph to 40mph and then it died and would not restart because the battery died from cranking it so much. I read a couple of other peoples posts about simular issues. The fuel cap hole is cleaned and the pet---- is also clean letting fuel pass through.

Needless to say I'm tired of pushing it home so anything that would help is greatly appreciated.
« Last Edit: September 30, 2020, 12:35:14 pm by 1977cb750A »

Offline 05c50

  • 05c50
  • Hot Shot
  • ***
  • Posts: 747
    • Classic Motorcycle Solution
Re: Cb750a Issue HELP
« Reply #1 on: September 30, 2020, 12:55:50 pm »
First you'll need to decide if it's a fuel delivery problem or an ignition problem. If it were me, I'd go for a ride with some tools in hand. When it quits open a carb bowl drain screw to see if there is fuel in the bowl. Then plug in a spark tester and see if there is spark at the plugs. Now that I think about it, you might want to do it in the reverse order, you don't want an ignition source on the gas that you just drained.

Wear a helmet,the life you save may be your own.Ask me how I know.               CB650C,CB550F,GL1000,CB750A

Offline PeWe

  • Really Old Timer ...
  • *******
  • Posts: 10,771
  • Bike almost back to the 70's 2015
Re: Cb750a Issue HELP
« Reply #2 on: September 30, 2020, 08:11:27 pm »
Maybe ventilation in tank that is clogged by rust?
Try to ride with cap open very carefully to avoid fuel tsunami.
Or petcock clogged, the filter make fuel delivery very slow.

Offline 1977cb750A

  • Full Member
  • *
  • Posts: 2
Re: Cb750a Issue HELP
« Reply #3 on: October 01, 2020, 07:06:26 am »
I think its more of a fuel issue with the tank. We had some bad premium lots of water (its drained on the side of the road) so i guess ill have to clean out the whole tank maybe replace the pet----

Offline Randy Nevrotski

  • Randy
  • Full Member
  • *
  • Posts: 32
Re: Cb750a Issue HELP
« Reply #4 on: November 02, 2020, 06:46:23 pm »
try starting fluid . when it shuts off spray some to see if it starts . BE CAREFULL . if it starts up then fuel problem . then open each bowl to check for gas if all full the carbs have to come off and clean . if u have to take carbs off make you pull all 4 slow jets and press them back in all the way.
1976 CB750A & Other bikes 1980 KZ 650 cafe racer 87 ZX750R NINJA 2001 KATANA 600 1983 GPz 750 1980 CB750 CUSTOM Past bikes 1974 suzuki GT750 TRIPLE Care Free Custom chopper 117 motor 95 Honda XR650L Dual Sport 87 ZX600R NINJA Honda CB550FOUR 87 Yamaha 225 trike honda 250R trike RM80 HONDA TRAIL CT70