VF700J interceptor issue

so i see where Timbox has a thread pulling these carbs off, but i'm not sure i need to go there yet.

Last Sept i drove this bike down the road about 3 miles. it started fine, took off great, ran up to i'm guessing 7000 rpm up and down the gears no sweat. it would start to stumble around 7K and it seemed eirily like my xj700 i had, before i replaced the battery - to frame wire, which fixed everything. so that's what i thought it needed.

So my brother in law passes away (his bike) and passed it to me. Three weeks ago now i tried to drive it home.
Started right up again, warmed up, revved up seeminly ok, i coast it down the driveway and head for home. After i get to second or third this thing just wont rev up past about 5000 rpm. it gets there and just stumbles, falls flat on it's face. it will still idle fine, revs to 4 or 5 no problem, just wont GO. i'm on a highway with a 50mph speed limit and i need to get this pig off the road. which i do and trailer it home.

So i read on the V45 site like one thing re carbs. that site is really bad. no posts on anything it aint nothing like this one. one guy said he had good luck just dumping Seafoam into the gas Run it long enough to get into the carbs, and letting it sit a couple of days. i tried this and nothing. tried it again after i dumped the rest of the seafoam into the tank and let it sit the last week or so and still nothing. it starts great (i did buy a new battery before i trailered it home), idles perfect, revs up to 4 or almost five no problems. then just wont go past 7 for nothing, even got hot and spewed antifreeze onto the engine last week. i didnt let it get that hot this time. i didnt think it got that hot from looking at the gauge for it to do that btw, but i didnt want it to happen again.

i see a place for new carb boots, rebuild kits, and a guy who will rebuild them for $300 kit included. there is also a great picture tutorial on removing and rebuilding them BUT!!!! can anybody tell me what else to look at, look for, try out or offer any idea on wtf is causing this thing to do this??? i have not checked the plugs, the fuel pump is working, it clicks about every 2 seconds when i am trying to rev it. the air filter is brand new and unobstructed, gas is flowing well, i almost think it could be ignition. HALP!

 

fuel filter would be something to look at.

 

i agree! it would actually be something to look at before posting any questions online. so i guess i shoud have lead with that.

on this rig the fuel filter is right next to the fuel pump i said i checked. changing the filter was the 3rd thing i did after 1-replacing the battery and 2-checking the airflow.

getting back to the fuel pump, it seems it should be pumping harder when it's at 4000 rpm trying to get up to 7000, a LOT harder. but it just keeps going at the same pace, about one click every two seconds. the filter is see thru, and it's staying almost full the whole time, not getting sucked dry, so i kinda ruled out the fuel pump.

 

If you remove the hose after the filter and pump that goes to the carb with ignition on it should fill a small jar in about 30 seconds.

 

Could be a few things... I do think lack of fuel is the issue with a second thing being the diaphragms may not be working as they should. If I remember right, you should be able to prime the carbs by turning the ignition on and then flipping the engine cut off switch on the right bar. That should make the fuel pump "click" every once in a while without turning over the engine. It is a hit or miss thing but a great way to Prime the carbs.

Myself I would have to pull the carbs no matter what. I would not feel comfortable or reliable riding the bike without knowing what the inside of those carbs look like. For me it is a given to take a look at any used older bike I get, never know what is in there and damage from sitting.

If you do pull them please take your time and if you have a heat gun use it on the boots. There is a very slight angle with the carbs coming out and going in that is the golden angle. It seems it is most critical just as they are going in. Within a 1/2" or so is the take your time and do it right moment. I have done several of these bikes and my first one I cracked the air box top by not taking my time and using something way too big to pry that carbs in place.

There are some great Youtube vids out these using ratchet straps and also how to bring the life back to those old boots.
http://v4musclebike.com/forums/showthread.php?t=13477

Good luck with that her, I hope it works out well.

 

thanks timbox, i was going to pm you till i saw your post. i know my pump squirts gas out when it's not hooked up but i never measured it yet. i figure the carbs are primed if it's been running and warmed up.
Would you rule out any coil issues? i found the tutorial at v4Dreams.com/maintenance btw Not looking forward to pulling carbs and pulling apart square o-rings. i kinda figured it might come to that so definitely will try to fill up a small jar in 30 seconds. pretty sure it will. i've got really small jars around here. small jars, large jars, in between jars.

thanks to all the above.

 

For the coils I would have to check if the bike will go above 7k RPM when the bike is just started and take her out. That will not give the coils enough time to heat up before the wires start to separate or error. If I remember that used to happen to one of my shadows some yrs ago. Once the bike got warm it would cut out and or die. It was the coil but only after it warmed up.

As far as the carbs go, just take your time, don't think it will be simple but have all the right tools. Take a look all around the carbs when you start to pull them as there seems to be a few things that might hand you up. I think the water temp gauge on the upper right side of the water hose coming from the radiator is also attached to the air filter box.

Just taking the air box off the top of the carbs has two hidden screws that will take a long Philips screw driver to get to. I don't know if you have to brake your carbs all the way down. If you don't have the correct tools and a impact screw driver then don't try to take the cabs off the connecting air box. I have had success just taking the cards down as far as I can with them still connected to the air box.

Do the cold run with the coils to see if you can get above 7k rpm and then look at the carbs.

 

that wont hurt the engine? and if it was one or two coils, it seems like i'd have the rest firing. this thing just totally tanks at 5-7K

 

Didnt work there timbox. i did get it to go to 6000 for a half a second, then the rest of the time it wouldnt go past 3000. i gave it about a minute to get the oil flowing.

 

So if the coils were cold and it still stopped at or about 5-7K you can maybe rule them out. I would still test them, easy to do. If "you" have never cleaned the carbs "you" really don't know what shape they are in. That is up to you and how comfortable you feel about digging into them. If there was some dirt in the bottom of the carbs and it was running nice until you got on it, that alone could have sucked the sediment into the jets.

For the test you don't have the engine on a load? Load being in gear and you riding it. I only ask because on your first post you said you were riding when this first happened and now I don't know if it is doing the same thing on the center stand or if you are riding again.

If you are just revving the bike up on the center stand and can't get it to go above 5-7K then you are looking at cleaning the carbs. There could be a vacuum leak too but I think you would see more issues around idle. Are you having stumbling, back firing and popping going on?

How did the pump test go with filling up the small cup/bottle with fuel?

 

ok. the fuel pump filled this bowl up in no time flat. FAST. today i started it. before it warmed up i gunned it. went up to 7-8000 the first flip. (i didn't leave it wide open), then the second flip bogged after 3000rpm. tried reving it, wouldn't go past 3500. damn!

 

So what does that tell you?

 

seems like it's telling me i have to take the carbs off. but i'm not a bike mechanic. i'm used to only having one carb to screw with. i was able to take my maxim into a shop to do that a couple three years ago. now that guy has died, and the shop is like any others, telling me if your bike is this old they wont work on them. so it's on me this time. i took the carbs in and out of the Maxim the first time, had to buy new boots for one side, don't remember which, but they didn't make the boots for the other side. it was a bitch.

 

Well you think the Maxim was bad...you have just stepped up your game. I will not do another Magna or Saber because of the carbs. I have done enough now that I can get them out in 30 or so mins. Watch as many vids as you need to and talk to the folks over here http://v4musclebike.com/

They really know what they are talking about with the V4's and should be able to help some too. This site is GREAT too, but the other site is just for the V4's. Good luck.

 

thanks, i was needing a good site!

 

I was reading about the v and it was recomended to tap on the tci to see if it starts to fire odd test but I sounded like they do that with results

 

welp, wtf not? i haven't pulled the tank or fairings yet so....where is my hammer? thx!

 

tried to tap the "tci". its under the tank. it basically ran out of gas before i could tell anything. it was barely running and able to idle, and there i am tapping on it and blipping the gas. not like an Maxim. mileage is 30,000 and the plugs looked pretty good although a little gassy. i looked at them after my tci experiment. it's looking like a carb pull is in the cards. sad face

 

well popping off the carbs was a snap! wow, easy! i pulled off the bowls and they are full of crap. looks like sawdust but i assume it's dried up gas. so off to Billysoutback.com for a $300 rebuild which they need anyway. i'll check spark when it gets back. jeeze! $40 just to ship at the P.O.! Oiee!

 

I am glad you went for it and they came off nice for you. Check those boots on the carbs to make sure they are not cracked. I put a little PB blaster on them to keep them oiled up for the install. On our carb bikes if things are not running correctly with the engine, always check them carbs. Now would be a good time to check the gas tank for floaters, rust all that good stuff. I know above someone mentioned a new fuel filter, great idea.