vaccume advance question

[Nightengale]

is there any reason the vaccume advance is connected to the number two carb, because i am setting my fj carbs to work with the vaccume advance and wanted to make sure it worked as it should. my thinking is that it shouldnt matter which carb it is connected to. Any advice would be greatly appreciated, i just want to make sure i am doing it right.

[jjz28]

I am not sure about that but i do know the connection on #2 is metered because i hooked my advance to the carb boot nipple and it started clanking because of too much vacuum so the one on the #2 carb is just the right amount of vacuum at the right time. It also makes a huge difference on how the bike runs with a load. My bike would rev awesome until i put it in gear to take off then i would have to rev it to move until i figured out my vacuum was unhooked then it ran great when i hooked it up.

[BA80]

As long as the vacuum is ported, that is no vacuum at idle, it shouldn't matter which carb you use.

[Nightengale]

thanks

As long as the vacuum is ported, that is no vacuum at idle, it shouldn't matter which carb you use.

thats what i thought.

[natemoen]

I honestly think it is just put on an inside carb for protection of the nipple so that it does not get hit and snapped off.

[Nightengale]

I honestly think it is just put on an inside carb for protection of the nipple so that it does not get hit and snapped off.

that does make sense

[TopCatGr58]

Hey Folks,

He said he has FJ carbs, not XJ carbs, I just looked at the fiche and they don't show any vacuum ports on the carb bodies, just the fuel inlets, and the vent T's...surprised to see vent T's....Yamaha was able to eliminate those with the later style XS carbs, so wondering why they put it back on the FJ carbs?

But, we've talked about the vacuum advance vacuum source before, and you can't put it on the INTAKE BOOT port, the #2 XS/XJ carbs have the proper metered and controlled vac. port for the vac. adv.!

There has also been discussion of folks drilling a NON-XS/XJ carb to put a vac port on the carb body behind the butterfly valve.

T.C.

[natemoen]

Yeah, he is looking at drilling the FJ carbs for the vac advance.

[WMarshy]

Hey Folks,

He said he has FJ carbs, not XJ carbs, I just looked at the fiche and they don't show any vacuum ports on the carb bodies, just the fuel inlets, and the vent T's...surprised to see vent T's....Yamaha was able to eliminate those with the later style XS carbs, so wondering why they put it back on the FJ carbs?

But, we've talked about the vacuum advance vacuum source before, and you can't put it on the INTAKE BOOT port, the #2 XS/XJ carbs have the proper metered and controlled vac. port for the vac. adv.!

There has also been discussion of folks drilling a NON-XS/XJ carb to put a vac port on the carb body behind the butterfly valve.

T.C.

I think the folks you talk about are the ones who use the ZXR carbs. Do a search and you will probably find some tips on where to drill the hole and how big it needs to be.

Im interested in hearing how well the FJ carbs work. Keep us posted and if you can, write a how-to. Im going Friday to pick up a FJ parts bike and have been wondering if the carbs/exhaust can be used on the XS.

[Nightengale]

read it

I think the folks you talk about are the ones who use the ZXR carbs. Do a search and you will probably find some tips on where to drill the hole and how big it needs to be.

Im interested in hearing how well the FJ carbs work. Keep us posted and if you can, write a how-to. Im going Friday to pick up a FJ parts bike and have been wondering if the carbs/exhaust can be used on the XS.

i read that forum and know where to drill the hole, i just wanted to know if it mattered which carb to do it on. and from what i have read on here they have been used before on these bikes, and have had good reviews. So far all i can say is that there was no problem fitting them to the bike, and the guy that i got the carbs from set them up to use a single cable instead of the push/pull cables that the fj uses.

also TC i was looking at the vent T's what are those for exactlly.

[GARTHXS]

id like too see what you come up with , because I havent the heart to drill into mine yet .

[WMarshy]

i read that forum and know where to drill the hole, i just wanted to know if it mattered which carb to do it on. and from what i have read on here they have been used before on these bikes, and have had good reviews. So far all i can say is that there was no problem fitting them to the bike, and the guy that i got the carbs from set them up to use a single cable instead of the push/pull cables that the fj uses.

also TC i was looking at the vent T's what are those for exactlly.

Let us know how what he use to convert it over to pull cable.

[BA80]

I think if you try to drill them all you'll end up with is a FUBAR set of carbs.

You know those POs we laugh at and hate at times? Don't become one.

[WMarshy]

I think if you try to drill them all you'll end up with is a FUBAR set of carbs.

You know those POs we laugh at and hate at times? Don't become one.

LoL

There's no reason to believe that... the ZRX carbs worked fine with a hole drilled into them for vac advance...

[Nightengale]

not me

I think if you try to drill them all you'll end up with is a FUBAR set of carbs.

You know those POs we laugh at and hate at times? Don't become one.

I am not going to do it myself, the guy i got the carbs from is going to do it for me, he has a full machine shop and builds drag bikes for a living. yeah the last thing i need is to mess up my new carbs. so i will leave it to the pros. and i will ask him what he had to do to set the carbs for the single cable. I have to call him tomorow and will ask him then. on thing about my carbs is that they were originally set up to be used on a legands race car, and as far as i know all he did was to put in a heavier spring in it for the single cable to work, but i will check.