idling issues

[jonesm]

hi im new this site just wondering if anyone could help??
just got me a 1998 VTR firestorm 1000 second hand with 42,000 on the clock, bike rides beautiful with no major issues , not knowing the service history i did the plugs ,oil,filters , the idle is set at 1,300rpm but it fluctuates between 1,300 and 2,000rpm when reved it doesn't miss a beat or backfires , i've checked all the simple things like the vacuum hoses fuel lines changed the plugs and cant find a fault , only thing i did find when disconnecting the tank is that the petcock is leaking and wont turn off , would this caused and idle issue if it wasn't getting enough fuel to one of the cylinders or getting too much fuel to one of the cylinders ? so before i pull the carburetors apart and try to clean and balance them does anyone have any ideas to try before going to the extent of pulling things apart thankyou

[8541Hawk]

If the petcock is leaking, then being it is vacuum actuated, you are most likely also dealing with a large vacuum leak.

Get the petcock sorted and see if the issue goes away.

[jonesm]

Thankyou for your reply I will be ordering a rebuild kit today was just throwing it out there hoping somone had the same issue and it was an easy fix

[popkat]

Sometimes the diaphragm in the fuel tap can get stuck, put a piece of hose on the vacuum and suck blow hard a few times to see if it will shut off, you hear it click, leave the fuel lines on or you'll get fuel every where, remove them after a few goes and see if it's any better. If it works strip the tap and give it a clean, should be ok then.

As to your other problem, check the chokes cables haven't pulled out of the holders in the carbs by someone previously not fitting them properly, you'll need to pop them off for this, then balance the carbs, while you have the carbs off fit a permanent take off for the front vacuum it will much easier to attach your gauges.

[jonesm]

Thankyou popcat I apreciate your help I will try this today before I order the rebuilt kit, as for the carbs I will cheak out the choke cable as your mentioned I'm thinking it is a carb issue more than the petcock or a vacume problem, but I'll get the petcock sorted first than attack the carbs thankyou for your advice

[VTRDark]

jonesm Leave the 8mm tap on and if fuel comes out the spigots when you pull the fuel hoses off then there is an issue with the petcock diaphragm. Do as pokat says there in case it's only sticking. If it continues to leak then it is a faulty diaphragm. The 8mm tap is only there for emergencies when things go wrong, hence the rubber guard folded up under the petcock. It's there to try an prevent fuel from hitting the hot link pipe. Under normal circumstances you should be able to remove the fuel hoses from the tank/petcock without turning it off.

(:-})

[darkember]

Sometimes the diaphragm in the fuel tap can get stuck, put a piece of hose on the vacuum and suck blow hard a few times to see if it will shut off, you hear it click, leave the fuel lines on or you'll get fuel every where, remove them after a few goes and see if it's any better. If it works strip the tap and give it a clean, should be ok then.

As to your other problem, check the chokes cables haven't pulled out of the holders in the carbs by someone previously not fitting them properly, you'll need to pop them off for this, then balance the carbs, while you have the carbs off fit a permanent take off for the front vacuum it will much easier to attach your gauges.

While the carbs are off do the TPS as well.
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=29429

[jonesm]

thanks all i did take the tank of and disconnect the petcock i think the manifold inside was stuck as soon as i blew into the vacuum valve it clicked i did that few times put it back on the bike and didn't leak at all when the tap was turned off but it still did not fix the idol issue, talked to a local mechanic he things by the sounds of it it could be a vacume hose or an inlet around the carburetors that's leaking and told be to buy brake cleaner and spray all around the all the hoses and manifolds one by one, he said its highly flammable and would get sucked into the engine and the revs will go up and would be able to tell if its a hose if i cant find anything next step is to get him to do the carburetors pull them apart clean and balance them,

[VTRDark]

put it back on the bike and didn't leak at all when the tap was turned off

It should not leak when On either, well apart from a teaspoons worth.

As for the vaccum, there is only one which runs from the rear cylinder by the carb inlet rubber (manifold ) to the spigot towards the rear of the petcock behind the left hand side fuel line.
http://www.vtr1000.org/phpBB3/viewtopic ... se#p282579
The front cylinder vacuum take off seen from the right hand side of the bike should be capped off unless someone has run a another vacuum line for balancing purpose, scottoiler or something.

Instead of spraying around the carb inlet rubbers, why not first try tightening up the clamps in case they are loose.

(:-})

[jonesm]

hi cybercarl , so you saying i should be able to disconnect both fuel hoses and it shouldn't leak when its turned on ? ill check that today when i finish work i would have thought that if the tap is on the fuel will come out same as other bikes i have had in the past but this is my first twin so im new to the twins and there setups, i shall check the The front cylinder vacuum also and i did go through all the carb inlet rubbers they where loose but when tightened up i'm not sure if it made much of a difference the idling was still over the place but it didn't seem as bad that's why he suggested to spray just in case it is a split rubber or a vacuum leak, thankyou for your reply and i will be sure to check The front cylinder vacuum when i get home i'm just hoping its something very simple like a $2 hose before i get into taking the carbs apart

[VTRDark]

so you saying i should be able to disconnect both fuel hoses and it shouldn't leak when its turned on ?

That's right because it's not actually a tap for switching off the fuel in the sense that you think, Ie to remove the tank. It's for emergencies only if there is a failure and fuel starts coming out the bottom spiggot.
http://www.vtr1000.org/phpBB3/viewtopic ... 51#p387301

The front vaccum should be capped off as standard. It's the rear your mainly concerned with as this runs from the petcock. I only mentioned the front as someone may have run a hose from it for balancing or running a scottoiler or something. You would have to check this for leaks too if it's the case.

(:-})

[jonesm]

thankyou very much you learn something everyday i appreciate you advice and will check everything that you have mentioned and get back to you thank you