Rebuilt my carbs today...PTO side doesn't have any diaphragms in it???

[kilabez0]

2000 GTX 951, I bought 2 mikuni kits. The first one I rebuilt the MAG side used every single part. Then I go to the next carb and pull the cover off that houses the little fuel filter and see there are no diaphragms or anything, just the rubber o ring piece. Is that correct? I just thought it was odd to have so many spare parts as this carb doesn't have the large reservoir piece that the other carb has.

 

[Cstang50]

The mag side has the fuel pump on it so the other one won't use them parts..

 

[Mickirig1]

Make sure when you do them there is not a little piece in the fuel line between the carbs. May be a restrictive device to keep pressure up.

 

[kilabez0]

so cut open the fuel lines???

 

[Mickirig1]

It should be between two sections of tubing.

 

[kilabez0]

the small T fitting?

 

[mikidymac]

That is not correct. There is no restrictor between the two carbs.
The MAG carb has the fuel pump and it sends it to the PTO carb.

At one time there was said to be a restrictor in the return line but I have never seen one and it is built into the carb body. If you look at the hole under the fuel pump side cover you will see that the casting hole leading to the return fitting is much smaller to restrict the return flow.

The only place to keep an eye out for a restrictor orifice is the accelerator pump line. it is a small brass insert in the line.

 

[Sportster-2001-951C-Stock]

If it's an SBN46i the return restriction orifice is built into the fuel inlet plate on the side of carb body. Don't drill it out thinking it's a clog!!!

I'm not sure where the inlet restriction for the accelerator pump is located, I've forgotten. Probably there is one. If it's missing, the accelerator pump might suck the PTO carb fuel chamber dry for a brief instant and cause PTO cylinder to stumble/hesitate.

I have to mention I'm of the school to replace parts for the sake of replacing them for no good reason can become a bad idea leading to problems thus I don't feel compelled to always use the parts if the originals are still in great condition.

Sometimes I rebuild a carb without replacing anything, or maybe the customer gets a gasket or diaphragm free left over from another kit that was laying around from a previous job.

 

[Sportster-2001-951C-Stock]

so cut open the fuel lines???

If you blow through them and feel a restriction orifice then investigate. Might be an important calibrated orifice or a hunk of wadagaho.

 

[1of500]

There is one going to the accel pump but that's the only thing

 

[Sportster-2001-951C-Stock]

There is one going to the accel pump but that's the only thing

Might be easy to lose, confirm it's there and check under the bench or in the bottom of your parts cleaner screen!

I like to spread a large white cotton bed sheet over my bench while working on carbs, it's easier to keep track of stuff and see/find things you might've missed. Helps to avoid small parts being lost or rolling off the bench onto the floor.