who knows their vfr inside and out,vacuum lines inparticular

[badger4543]

hey guys i picked up this vfr a while back. ive been putting it back together finally BUT i have left over a rather large bit of vacuum line/breather hose it has a T peice in it.. currently the bike is running but breaks/bogs down at 4500-6500 im thinking this left over hose may have something to do with it. ive put new plugs and air filter, ect. i remember removing it but the hell if i can remember where its come from.. any help would be awsome thanks..

http://imageshack.us/photo/my-images/36/zo32.jpg/

[28hodge]

I think that is just the breater/drain hose from the airbox cover, but as i have no airbox cover on mine as its a track bike dont take my word for that, i doubt it is the cause of your bogging tho.

Is the fuel vacumm hose from the rear right inlet to the fuel tap well connected and in good condition/free of kinks, this acts as a fail safe for the bike, if the bike is not running and the fuel tap is left this stops fuel from leaking into the carbs/engine if your float valves are knackered.

If its old or incorrectly fitted you'll get fuel starvation issues, this could be causing your bogging.

If this all seems ok, have you got the rubber flap fitted, they need to run all the parts of the standard induction system really otherwise you will get running issues at various wind speeds etc.

[badger4543]

ill double check the vac line to the fuel tap.there is already a hose off the side of the airbox..

[CMSMJ1]

the vac lines do not have any t pieces

The t pieced line is an airbox drain definitely

[Neosophist]

didnt look at the pic but its the drain.

the drain that runs from the top of the airbox is for fuel acutally.. if you look at the top of the airbox theres a "dish" with a hole in it that runs to the pipe, under the tank theres a drain for when you spill fuel around the filler cap, this drips onto the top of the airbox and down that drain pipe.

the T piece pipe routes upto the tank breaether and then down each side of the bike.. check the service manual first few pages for diagrams of how it routes..

vaccum hose is small, breather hose has large OD, maybe 12mm?

what are your carbs setup as, is the rubber flap in place, usually issues sounds like

[VFRkieran]

Sounds like a similar problem I had, couldn't for the life of me figure out what this hose was for with a t piece in the middle, turned out it was just supposed to connect to the fuel tank breather hose. The bike will run fine without it unless of course it's blocked up.

On the vacume hose side of things if you don't know when it was last replaced then it's definatly worth doing, it can look fine but in fact be completely shagged when the bike is running.

[badger4543]

awesome as thanks for the info.
is the vacuum line a special type of line? is it solid not soft like most cars, im aware of the small one of the tank tap is there any others i should be aware of,

and not sure what the carbs are set at as i never got that deep into the bike im pretty sure itll be stock as i knew the family who owned it before me but it did sit for 3 years before i got it, does carby cleaner additive work like the stuff you add to the fuel?

another question regarding the tank breather how does it connect to the thing that screws into the tank? i haven't had a good look and a play yet but the silver bolt type thing with that usually has a hose hanging out of it can you reconnect the hose to it?

[VFRkieran]

Vacumme hose can be bought very cheap from Rick oliver find his stocklist in one of the sticky threads on here and have a dribble over all of the awesome bits he sells at decent prices.

I wouldnt worry about the carbs for now, get the fuel hoses replaced and give it a good long run to see if anything gummed up in the carbs clears with a good thrash, i havent got any experience with fuel addititives so cant answer that.

The tank breather is just a clear hose that pushes onto the nipple thats screwed into the tank, can be taken on and off as much as you like.

[badger4543]

so i think i fixed it.. one issue was tank was low on fuel turned to reserves and fixed half and i think the other half was i had the vacuum line on the wrong part of the tap i think i might have had it on the blow not the suck side of the tap.. i took it for a ride and was 100 times better but im not sure just how snappy the throttle should be. it does seem to have a little lack of throttle response but like i said im not sure how snappy it should be..

[Neosophist]

so i think i fixed it.. one issue was tank was low on fuel turned to reserves and fixed half and i think the other half was i had the vacuum line on the wrong part of the tap i think i might have had it on the blow not the suck side of the tap.. i took it for a ride and was 100 times better but im not sure just how snappy the throttle should be. it does seem to have a little lack of throttle response but like i said im not sure how snappy it should be..

if its been sitting for 3 years id follow cammos carb guide, get the carbs checked and cleaned and setup back to stock and go from there.. amazing how they can get messed around with over the years.