I'll see if I can post up a couple of pictures to better illustrate my issue.
BBB

 

just wanted to say, " THANKS! " since i bought my vtr, it's been a roller coaster of performance & emotions, running good one minute & dying the next ... i've had the tank & carbs off at least a hundred times, " tinkering " ... cleaned & jetted carbs, flushed tank ... & figured that my hoses might be wrong because, my gas cap was under pressure & would hiss, when opened ... looking in the shop manual they have no pics of the petcock hook up or the bottom of the tank ... i search ebay looking at tank pics, but, they're all stripped ... finally found your pics & realized that my pet **** was put together wrong, diaphragm was 180 out & the vacuum line was in the wrong spot. plus i had the tank hose on the bottom ... my bike runs awesome now ... " THANKS! "

 

Another victim of PVLIR

 

believe it or not, my bike was running for 2k miles with the PVLIR connected to the bottom nipple, not only that but it was leaning fuel into whatever is on the other end of the PVLIR. I have video to prove this. and my bike is fucked atm.

 

Bringing this thread up again...

For those of you who aren't familiar, I've torn my bike to pieces with reckless abandon, and am in the process of putting it back together. It's like leggos with very shady directions and more lethal if done incorrectly. I tore up two sets of incomplete carbs and took the best of both worlds, one de-PAIR'd and one not.

Ok, with that background, I'm having problems replacing all of the hoses and could use some guidance, as I don't even trust how it was put together before. Specifically, the vacuum lines. Water hoses I'm fine. Main fuel hoses I'm fine. The ones that I think that I'm a little fuzzy on are the petcock vacuum line (does this go to the carbs?) and the carb sync stuff.

I am still trying to puzzle together a full visual from my teardown pics (not to be trusted, remember!) parts websites and factory service/haynes manuals. I would like to make sure I have everything setup correctly. I do not have the tank with me as it's getting painted, and it appears that there are two hoses that go from there to somewhere too...

Haha if anyone can even figure out what I'm asking, you get kudos from me. Off to take pictures of my setup so far...

 

Ok, here are the question areas...

This pictures is of the RIGHT side of the bike, front carb/cylinder looking forward. I think this alan bolt in the lower left is undone during a carb synch? Don't need do do anything here, correct?


Next pic... same carb but looking down. I have what I think is another vacuum hose with a t-joint and a plug in the hose coming off that joint. Drainage hose perhaps? It seems to be in the manual as a vacuum hose.



Ok, moving to the LEFT side of the bike, looking backward at the rear carb/cylinder. This is the part that concerns me- I have this fitting that looks to want a hose on it. Again, seems to be part of the carb synch setup. The question is, which hose and what's it doing when it's not synching carbs. Should the hose be attached and then plugged?


Finally, this pic is pretty non descript, but its of the rear carb looking down. Here there is no t-joint in the carb hose like the front one... the unsymmetry is just something I am questioning- it could be fine?


Ok, like I said, I'm trying to piece together what's all happening, but the manuals and such all include the PAIR system, which eliminates about 2/3 of the hoses and confusion, but leaves me trying to figure out what parts are left and I need. The timespan that this project is taking me makes it hard to place everything perfectly correctly! Thanks in advance...

 

The little brass nipple is only used for carb synch. It should have a plug on it when not in use for that purpose.

 

Correct me if i'm wrong, but is'nt the brass nipple supposed to be connected to the vacuum line that leads to the petcock for fuel supply?

 

I'm hoping that this is the case. 'Cause then I have everything accounted for. I'm hoping also that the two hoses dropping down from the tank in the first pic in the thread (not the petcock) are just vent hoses and don't go anywhere...

 

Yes, for all bikes the rear vacuum port goes to the rear port on the petcock. I think CA bikes have something going to the front petcock port, but I can't remember for sure. Anyone with a stock CA bike care to provide clarification?

The lines off the bottom of the tank snake down to the left side of the oil pan. They are vents and drains. One is the internal vent (smaller), the other is the overflow (larger) that comes from where you put fuel into the tank - Basically the small hole under the fuel cap.

You DO know all this is in the downloadable service manual, right?

 

Yeah, I actually have a hardcopy of that and the Haynes manual... and I snoop around on the parts sites to get to what they don't tell me.

My problem was that in most of the systems, they only show a portion of the hoses (which is how I know I have the water lines hooked up correctly), or include CA instructions (hard to decipher) AND/OR include the PAIR stuff. I would be better off if I had no PAIR hoses, but one of my sets of carbs did, so I have a bunch of hoses left over and and awfully confusing time working out which was needed which was PAIR and which was CA. I think I have it straight now, it's just been awhile since I was ripping things apart and couldn't quite remember. If you look at the hoses on the attached pic, my brain just hurt figuring it all out. Especially since most references to the hoses in the manual were for maintenance purposes- as in they were already attached where they should have been

Thanks for the help... I think I have it all covered now!

 

SOOOOOOOO, after ripping that damn thing apart a half dozen times, (swapping out carbs to diagnose an issue) redoing every vacuum line, becoming very intimate with my carbs both inside and out.... it all came down to a misplaced vacuum line to the bottom of the petcock (PVLIR)... Thank you 7 moore .. again you bail me out.. so I guess I owe you at least a pallet of beer..... and extensive help on your jeep.

Ill drop off your carbs on Saturday ...

 

Zombie thread, but man did this help me with a little problem I was having. Totally went stupid and hooked the Vac line to the bottom fitting. Explains why I was getting dodgy fuel issues... Shop manual doesn't help if I don't look at it..

 

new question along this line. I hadn't ridden the bike for 7-9 months. It was running ruff on the low idle side so I pulled the carbs to clean them. My son has done them before and did them again. He said the jets were pretty well clogged. I put them back on and now it wont start unless the choke is all the way out and then still wont accept any throttle. Just stops. My son say it sounds starved for fuel and check the fuel lines and the filter. I see the filter is internal and doesn't seem to be recommended unless it's a high mileage bike. Mine only has 17K miles and its a 99.
What would be the suggested thing to check for these symptoms? I have no problem pulling the petcock and checking.

 

Make sure it is not PVLIR.

is the vacuum line going to the correct port on the petcock? Connect it to the back- not to the bottom of the petcock.

 

I have a question about what I think is a vacuum line off the front carb. In the photos from 7more7, it has a screw inserted in it. I assume my problem is that I didn't have it hooked to anything. Where is it supposed to go? The only thing in the area that looks like it can take a hose is the thing attached to the bottom side of the air box. I think that's the PAIR gizmo. It has something coming off it that looks like a hose should go on it but it is solid. If it goes there the hose would be closed off.

 

If you have a hose coming from where the hex screw as in 7's first photo then it should be plugged or capped off. If you are not the first owner and found it this way, the PO must have installed the hose for ease of carb sync.

 

It's in his second photo. It "T"'s off what the diagram calls the air cutoff valve. Its a black plastic piece that you can also see in his photo. Someone has put a screw in the end of the hose closing it off.

 

I took a chance and hooked that tube to the blank post that effectively closed it off.
Put it back together and it started right up. Now the problem is it needs full choke to start and shuts down the instant I try to add any throttle.
Thoughts anyone?

 

I'm having the same issue but I just replaced my se value or choke valve. My se valve broke where it connects to the carburetor after I replaced it the bike only starts if the choke is pulled in completely please help sounds like we had the same issue my vacuum lines are definitely connected right under fuel tank