Topic: Cb500 engine intertransfer of carbs from550

[wolfesteel211]

Can one use a carb from a 78 cb 500 on a 73cb 500 and what if there is a difference with needle jets float jets ect. Having problems with the bike running very rich?

[Deltarider]

I suppose yours is a CB500K3. If so, it has the later PDcarbs and not the old style Keihins. There could be a problem connecting the old style carbs to the rubber boots (both airboxplenum and cylinderhead). The parts inside the carbs like floats and jets are not interchangeble btw.

[wolfesteel211]

I apologize I wrote that backwards and just to make it easier it's as far as I see a it's 78 cb 550 with a swapped out 73 cb 500 engine .I am new to actually working on motorcycles and am having a hard time getting it running  . The previous owner did not let me know much about it so kinda of a learning curve . Any help I guys could give is really appreciated

[wolfesteel211]

Also there was probably no tuning of the carbs or adjusting the jets I assume they are still stock settings and prob the reason it's running so rough thanks

[dave500]

get your ignition spot on first.

[Deltarider]

get your ignition spot on first

I agree.

[wolfesteel211]

Thank you guys I will when I get home to take some decent pics and the it is an air box no pods

[wolfesteel211]

And I will look into the ignition thank again will update u

[wolfesteel211]

Here are some of those pics u guys asked for I went out and took them when I got home . Two weeks ago I could get the bike to at least start and run. This week nothing I check the battery and charged it fully. Checked plugs they where good. But when I checked for spark nothing . Arrgggh so I guess have a bigger problem to start with i assume ? I did have a fuse blow last weekend one of the 15 a I replaced them but nothing won't start thanks for any help

[wolfesteel211]

Let me know if the carbs are not good Enoch picture wise. I did take them apart and cleaned them well. They where pretty clean and made sure to make sure. all was clear by using carb cleaner and then pressured air . After putting them back together and checking float height it ran a lot better but still not where she needs to be

[wolfesteel211]

It will turn  but not all the way

[wolfesteel211]

Yes I had the battery hooked up I had took the pics right before I went inside and unhooked them . And I'm sorry yes it was originally rough running but would run and turn over. Today I went and tried just to see how she would sound and run but with a fully charged battery and good plugs no spark. The fuse last week I replace and did not blow again . The reason it blew was an exposed wire was loose and hit the frame I seen when it happened and was able to make sure it didn't do it again till I could get it fixed . When I got it in to the garage I check to see if the lights and signals would work they did but the started would not I put in the new fuse and it did . Today checked the fuses and she won't kick over. Sorry for the new issue just super frustrated. Seems like when I make any kind of head way another problem makes itself known. I'm now having to figure out the spark issue before I can even go back to the carbs . I think or should I worry about maybe doing all the wiring there is some wiring issues with it and none of it I had touched yet thanks for Ur patients

[wolfesteel211]

Thanks I will pick one up it was on the list . The battery is brand new and fully charged but I will double check. As for the points I will also. Check them and coils The start stop switch does  some times act up so I will order a new one. Should I get new wires and plugs and if so is there anything else u think would be a good idea most of the bike seems to be from 78  I thank u taking the time I will let u know as Soon as I get that multimeter and keep u posted thanks

[wolfesteel211]

Calj thanks so much. hack job is a definite with this after I get that meter I will take some pics once I get a few more questions answered. Have me a good start . The wire in question that blew the fuse I believe has something to do with the starter . It came down from it to a cylinder that sticks out horizontal then runs out into the nest I think u speak of so wish me luck I will keep u post thanks again for my uneducated questions youve been helpful. I will read up and educate myself on the parts a little better to.

[dave500]

get a little .177 air rifle cleaning brush for the small circular connectors.

[wolfesteel211]

Thanks will do