My Vmax performing like a 500cc

[radley]

No you do not have to take the airbox off- follow the wires from the fuel pump and you will find the end plug black 2 prong connector on the right side along the upper frame. You are going to need longer gas line to fit this pump on-There is a way to change the original bracket to the new pump if you are interested.

Ok, i took a peek yesterday and it seems like the fuel line from the pump is oriented differently on my new one, is that why I need extra length? do I need to use anything special or just get the same size fuel line regular hose at oreillys, or is there something particular about a fuel line i need to consider? i noticed on my fuel pump now, that the PO used a couple of zip ties on the one side, still had the bolts on the other. other than that , looks like only 2 top bolts hold the pump in place.. so whats easier, change original bracket as mentioned or get longer fuel line? i'll try and maybe get this taken care of after work today. I remember putting the air box on, it is tricky.... now out of the aribox there are those 2 spouts, one in front, one in back. the one in back goes where?...seems like it connects to a hose that goes to the center of the engine.. the front one is smaller, and I dont htink i ever had anything connected to that, is there supposed to be? the larger one in rear was tricky re-connecting,,, esp with the hoses coming out of the carbs that wrap around and screw into the airbox... tight fit with all those running around...

 

[blaxmax]

Ok, i took a peek yesterday and it seems like the fuel line from the pump is oriented differently on my new one, is that why I need extra length? do I need to use anything special or just get the same size fuel line regular hose at oreillys, or is there something particular about a fuel line i need to consider? i noticed on my fuel pump now, that the PO used a couple of zip ties on the one side, still had the bolts on the other. other than that , looks like only 2 top bolts hold the pump in place.. so whats easier, change original bracket as mentioned or get longer fuel line? i'll try and maybe get this taken care of after work today. I remember putting the air box on, it is tricky.... now out of the aribox there are those 2 spouts, one in front, one in back. the one in back goes where?...seems like it connects to a hose that goes to the center of the engine.. the front one is smaller, and I dont htink i ever had anything connected to that, is there supposed to be? the larger one in rear was tricky re-connecting,,, esp with the hoses coming out of the carbs that wrap around and screw into the airbox... tight fit with all those running around...

You are going to need longer fuel line and what you have on there stock is in mm's. There are 2 different sizes of fuel line also.
You can take your old fuel pump apart and put the bracket from it on your new fuel pump but you have to get the large rubber diaphragm to go through the metal disc-kinda tricky but fold it then pull it through. The 2 bolts on top are the only mounting bolts for it. You can make the new pump fit into the holding bracket but it will not bolt up- it just fits kinda tight and doesn't move with the fuel line hooked up.
On your airbox remove your radiator overflow tank to clearly see the crankcase vent tube and use either your fingers or needle nose pliers to connect to the rear hose on the airbox FIRST before you try pushing down over the manifold rubbers. The nozzle in front on the airbox goes to nothing. It is just for overflow-I ran a hose from it down below the engine for drainage.

 

[wayne z]

I bought one of the 25 or so dollar Ebay pumps that has the end plate held on with screws, for my 85 Vmax. I used the original mounting bracket and end plate on the new pump. Fits and works perfect, same as factory with the plumbing and mount.

 

[wayne z]

just got the new pump here at work.

Do i have to take the airbox off in order to disconnect the plug and connect new one? I had a hard time getting that airbox on. Was tough getting booties onto carbs. we took out the individual booties and slipped them on the carb, zip tied them closed up a bit to fit thru airbox bottom, puleld them through and worked the plastic bottom past the notch... re hooked up the plastic parts connecting the sides, etc.. it was tough.

anyways I'm assuming I gotta do that too. prolly gonna be easier to work around anyways, that everything is a tight fit with the Vmax it seems.

I learned a trick about them booties. Mine were hard and deformed and not sealing well. I heated them with a heatgun and snapped the airbox in place easily then tightened the clamps. Now it plugs back in easily when it's been removed.

 

[radley]

I learned a trick about them booties. Mine were hard and deformed and not sealing well. I heated them with a heatgun and snapped the airbox in place easily then tightened the clamps. Now it plugs back in easily when it's been removed.

Thanks for the tip... I got a heat gun, I'll try that out... soon....BECAUSE....

MY BIKE IS A ROYAL PIECE OF FLAMING POO!!!

So, i got off work yesterday and decided to try to install the new pump I purchased on Ebay. Blaxmax, you're right and I didnt notice the whole thing about switching out the bracket etc, but I first removed the old pump... no biggie there.. then I saw what you meant about taking the bracket off old one, and the whole thing about the big diaphragm having to go over the new bracket center hole... now... your directions could have been a little more detailed to help me out, but I like how you guys make me figure some things out on my own... it's cool....make me struggle a bit....

Anyways so, I first took the bracket off the new pump. this can be removed without disassemble.. then I saw that I had to disassemble old one to remove the bracket...the bracket doubles as the, let's call it "metal washer piece" that is part of the 3 screws that connects to the main pump body, and holds down the red/orange gasket(s) that are between them.... So reference purposes, lets label these parts. top lets call "nozzle piece", next is the black cylinder it sits on top of, lets call that "nozzle base" piece, then there's the "washer piece" that the large diaphragm has to go over, then there are the gaskets then the main body piece.

Ok, so I read Blax's post about fishing the diaphragm through the hole and putting the old bracket on new pump. at first I couildnlt see how it woiuld fit, then I realized that the new pump has that washer piece, with little casted "*******" that fit onto the main pump body piece,...so it will only fit 1 of three orientations. so I removed the nozzle piece, one bolt being yellow (why?), and in doing so, the nozzle base comes loose, pulled that off. The innerds of the new pump look different, there's no small black diaphragm thing as seen in earlier threads and pics... anyways, I realized I had to remove the washer piece, and replace it with the old pump's bracket. I tried to orient the bracket close to what was there such that the pump will mount with nozzles pointing towards carbs. Now, the nozzle piece must be oriented on the nozzle base a specific orientation, I think I got this right...as it looks like there is only one way such that the nozzles are over the chambers in the base... so, does the nozzle base have to be oriented on the main pump body a specific way? I'm not 100% sure I did this, but I think so based on the pic I took before disassemble...

so anyways, took off the washer off new pump, replaced it with old pump bracket, lined up the screw holes and "*******", and gaskets (2 red/orange ones) and tightened it up. i pulled the diaphragm through as well. now I put the nozzle base/nozzle pieces on and tightened it up. I then looked at the old pump pic of orientation of nozzles versus bracket and realized I didnt orient it such that nozzles pointed toward carbs. I then moved bracket piece such that it looked as good as it couild get. Now, the 2 nozzles on new pump, one is larger, one is smaller. I am assuming the smaller one goes to carbs. Larger one goes to fuel filter.
I didnt have too much trouble getting the line on the smaller going to carbs, and tightening with screw clamp. the line going to fuel filter, i had a tough time getting it onto nozzle adequately as nozzle is much bigger, this is a new line that I bought at oreillys b/c I needed more length, thanks blax, if that's what you were takling about. as far as I know, the length to carbs was adequate with existing hose. filter, pump side, outer diameter smaller than large nozzle on pump,, so it was tough getting on there but I think I got it enough, and tightened with clamp. plugged pump in, tightened bracket nuts, new puimp installed with old pump bracket.

Now moment of truth...

I turn key and fuel fills up filter immediately..looking good. Bike starts up. Keep in mind newly rebuilt carbs, haven't set idle, haven't set sync, haven't adjusted A/F screws (out 2 1/2 turns from carb build).

Bike running and I'm hoping to get some miles on. Things soon starting to not look good again.

Bike running and warming up, but I soon have to keep Choke on full. Choke lever at full has bike running at 4K rpm. Lower choke a bit and bike initially slightly revving up a bit and down on it's own. Try to twist throttle and starts to bog out. Fuel filter no longer full and not staying full. It's like I didnt change a damn thing. after a while it was getting real hot, fan started up to help cool down. didnt run it long like that, shut her off and threw in the towel.

choke enrichners snap back into place after I pull choke lever down... maybe that's the way it's supposed to be, but choke lever won't stay down, so I had to hold it with my foot to keep bike revved up and twist throttle to show you guys what happening. videos not real good, i'm starting to get pissed and impatient. Ready to say eff it. I don't know... I just don't know why this bike is ill.

https://youtu.be/sKzNXvwEYzs

https://youtu.be/Lk_-BRn7yt0

After work today I'll drain carb bowls and see how much fuel comes out of each.. after that I'm rolling the bike to the curb and putting a sign that says Best Offer... right next to my piece of sh*t car.

 

[Dorney]

Maybe this has already been mentioned but have you checked the vent line to the tank to make sure it is opened.

Dave

 

[radley]

Maybe this has already been mentioned but have you checked the vent line to the tank to make sure it is opened.

Dave

I sucked up gas via mouth with little effort from the line gas tank to filter. I will blow in there this time (smarter...lol) and listen for bubbles with gas tank cap off. Maybe get a new filter, but when I had it off yesterday, i had no problem moving air through, both directions...seemed uninhibited..

someone also mentioned they stuck some bike cable or something through there to unclog theirs, I can do that too just in case....

 

[blaxmax]

If you can keep it running for one minute while sitting on it touch each cylinder with your hands and see which one is not hot and not getting fuel-you are not running on all cylinders. Have you checked the float levels?
If that pump runs a short while and then shuts off it is working properly --empty each bowl and measure how much gas is in each carb. That video sounds like you are not running on 4 cylinders.

 

[Dorney]

If you can keep it running for one minute while sitting on it touch each cylinder with your hands and see which one is not hot and not getting fuel-you are not running on all cylinders. Have you checked the float levels?
If that pump runs a short while and then shuts off it is working properly --empty each bowl and measure how much gas is in each carb. That video sounds like you are not running on 4 cylinders.[/

Dave

 

[wayne z]

I sucked up gas via mouth with little effort from the line gas tank to filter. I will blow in there this time (smarter...lol) and listen for bubbles with gas tank cap off. Maybe get a new filter, but when I had it off yesterday, i had no problem moving air through, both directions...seemed uninhibited..

someone also mentioned they stuck some bike cable or something through there to unclog theirs, I can do that too just in case....

That was me, talking about cleaning out the fuel feed tube from the tank to the filter. the other poster is referring to the tank vent line that passes down in front of the battery box.
In the line, and with a screw fastening it to the battery box is a little valve that keeps gas from comimg out the vent line if the bike is tipped over. They are VERY bad about getting clogged, mine was, and a spare i found was also stopped up so I got a 3rd used one from Sean and it works. Try running with the gas cap off to see if it has any positive effect.

 

[radley]

Gas levels from float bowls in the pic, also described in video. Front left, bottoms section, back left, next up, back right, top section, front right was empty. I saw this before as well, before carb rebuild...what does that mean?

As far as float bowl level, I did my best in carb rebuild to line up the float curve with the top of the circle that is on the jet block... I didnt record all my every move on the rebuild but as far as I know and would tell anybody is that yes, I set the floats correctly per the rebuild video....

https://youtu.be/gMfn9F3AJxk

Do I have to remove carb rack and take apart the carbs and confirm all float levels? ummm, yeah, just what I want to do at this point..

So, Ok, as far as "tank vent line that passes down in front of the battery box. "... I did try to run it with gas cap off, didn't help but I will try to find that tank vent line and make sure not clogged up... i can try again with gas cap off.

 

[blaxmax]

No, you leave the carbs on to do a wet float check and you should measure the float bowls one at a time or separately so you know if there is any difference between the carbs----Did you try and find the colder cylinder? Maybe try a compression test?
http://www.vmaxforum.net/showthread.php?t=17274

 

[radley]

No, you leave the carbs on to do a wet float check and you should measure the float bowls one at a time or separately so you know if there is any difference between the carbs----Did you try and find the colder cylinder? Maybe try a compression test?
http://www.vmaxforum.net/showthread.php?t=17274

I did measure one at a time,,, see the lines on the bottle? black lines? i think I mentioned this but front left carb, is bottom, left rear is middle, right rear is top, and nothing came out of the right front so that's why there are only 3 on the pic of the bottle.

I'll do wet float check after work today, thanks. Also I can grab a compression tester from autozone and see what's going on with that cylinder... maybe grab that before i head back home after work..

doesn't look like its very accurate though, lol, after reading the wet test.. so float level wet test is really measuring how much gas is drained out of the bowl...? as far as the clear tubing,, doesn't the inside diameter matter as far as the 15-17mm? I gotta read it again, isn't quite clear to me 100%.

havent found colder cylinder, but obviously front right by looks of it probably.... I'll fire it up for a minute and try to check tonight too.

 

[Nubicon]

I did measure one at a time,,, see the lines on the bottle? black lines? i think I mentioned this but front left carb, is bottom, left rear is middle, right rear is top, and nothing came out of the right front so that's why there are only 3 on the pic of the bottle.

Smooth sided container, drain one bowl at a time. Dump it in between. Hopefully all 4 are almost exactly the same.

I'll do wet float check after work today, thanks. Also I can grab a compression tester from autozone and see what's going on with that cylinder... maybe grab that before i head back home after work..

It's a quick test and all of this is for naught if you have some mechanical damage. More knowledge is never a bad thing, especially when it is easily obtainable. If you do a compression test fix that battery or starter. It sounds really weak. Also keep a battery charger on it while you test each cylinder. Lower and lower voltage will result in a decline in compression numbers.

doesn't look like its very accurate though, lol, after reading the wet test.. so float level wet test is really measuring how much gas is drained out of the bowl...?

No. Wet testing measures how much fuel is in the bowl under fuel pump pressure before the needle stops the flow. This is where the 17mm measurement comes into play. This video illustrates the type of setup you'll need to check it out, even though he's testing something else.

https://www.youtube.com/watch?v=URf9HlaAnto

This diagram shows how it works. The clear tubing allows you to see exactly where the fuel is inside the carb because liquids seek their own level. Your carbs have a raised notch on the side just behind each diaphragm cover. That's the mark you want to be 17mm from with the drain open and the key cycled on until the pump stops.

as far as the clear tubing,, doesn't the inside diameter matter as far as the 15-17mm? I gotta read it again, isn't quite clear to me 100%.

All that matters is that you can safely couple it to the drain line without leaking. Keep the potential for disaster low!

havent found colder cylinder, but obviously front right by looks of it probably.... I'll fire it up for a minute and try to check tonight too.

Good luck, it'll be worth it when this thing accelerates right. unk:

 

[VMAXXIMUM]

Radley, I also had trouble understanding the wet float check. If you still don't understand it 100% give me a call and I'll be glad to clarify any confusion.

Christian
401-439-2609

I'm up til midnight so don't worry about the time. I live on the east coast so I'm at least 2 hours ahead of you.

 

[radley]

heres a recent vid....with the what cylinders are hot question.

back left got hotter faster, others not quite as hot in amount of time running..

https://youtu.be/HuYS5_V9F9s


maybe sync has to do with this, but the left rear was about twice as hot as the rest of them....

 

[blaxmax]

You need a carb synchronizer-Your carbs are out of sync.
You should set your a/f mixtures screws 2 1/2 turns out then sync the carbs.
Have you had the spark plug wires off? Check and see if the front 2 wires (closest to the radiator) are going to the opposite cylinders. The coil on top of the cylinder on the left front needs to be plugged in to the right cylinder and visa versa.

 

[radley]

You need a carb synchronizer-Your carbs are out of sync.
You should set your a/f mixtures screws 2 1/2 turns out then sync the carbs.
Have you had the spark plug wires off? Check and see if the front 2 wires (closest to the radiator) are going to the opposite cylinders. The coil on top of the cylinder on the left front needs to be plugged in to the right cylinder and visa versa.

I made a manometer for when I first rebuild carbs 2 summers ago, probably not quite as precise as others a guy can buy for what,, 100 bucks.. lol like i' haven't spent enough on my vehicles recently.. anyways I will do my best to sync the carbs.

when I rebuilt them, I did, at leaet what I though, set the A/F screws 2.5 turns out. I'll double check that first. one concern though, i know when you screw those A/F screws in, you are depressing the spring, and the turns get tougher... I hope I don't go too far and break the A/F screw.. 2 of mine were broken when I took apart carbs and rebuilt them.. ordered all new ones so they should be set right, but again, I'll double check..... Also gotta find that sync screw thread, have it somewhere too.. i think the ONE sync on left side syncs left front and left rear...then there are 2 on right side.. I think the rear one syncs right front with right rear, then the forward sync screw syncs the 2 pairs together....right?

I had the spark plug wires off when I replaced the spark plugs couple months ago along with all fluids etc.. did them one at a time so no way they got crossed... unless they were when I bought the thing 17 yrs ago. didn't do much in my younger years, dindt know much or have ppl around me who did..

 

[blaxmax]

I made a manometer for when I first rebuild carbs 2 summers ago, probably not quite as precise as others a guy can buy for what,, 100 bucks.. lol like i' haven't spent enough on my vehicles recently.. anyways I will do my best to sync the carbs.

when I rebuilt them, I did, at leaet what I though, set the A/F screws 2.5 turns out. I'll double check that first. one concern though, i know when you screw those A/F screws in, you are depressing the spring, and the turns get tougher... I hope I don't go too far and break the A/F screw.. 2 of mine were broken when I took apart carbs and rebuilt them.. ordered all new ones so they should be set right, but again, I'll double check..... Also gotta find that sync screw thread, have it somewhere too.. i think the ONE sync on left side syncs left front and left rear...then there are 2 on right side.. I think the rear one syncs right front with right rear, then the forward sync screw syncs the 2 pairs together....right?

Your sync description is correct.

 

[Dorney]

Your sync description is correct.

Blax you can correct me if I'm wrong but the left front doesn't have adjustment it's what you set the rest to. Also the right front adjustment is for the right front & right rear is for the right rear.

The A/F screws shouldn't turn that hard that you feel there going to brake.

Dave