Hesitation in revs

[Steve6088]

I am in need of advice again. Last week my bike started idling at 2k rpm and the revs were slow returning down. I thought choke was sticking but it dosent feel like it is.

I have turned the tickover right down to ~1.2k again but the revs hesitate on their way back down between 3-2k. I know sod all about carbs so I dont know where to start . The air filter looked a bit dirty, could this even be the cause?

The bikes revs used to drop back down fine

Thanks

[VTRDark]

Start with cleaning/changing the air filter if it's that bad as this will upset the mixture. It's probably worth doing a carb sync as well as these are all easily done. At the same time you may as well lube the choke cable just in case it's sticking and while you at it also do the throttle cables.

What set up have you got? has any carb work been done before, jets, tps, air filter change. As for the revs used to drop back down, don't forget carbs will fluctuate throughout the year due to use, temperature and humidity changes.

If any of these don't resolve it then your going to have to dig a bit deeper and maybe take the carbs off, strip down and clean. You should be able to have the bike idling at 1000-1200 rpm with no fluctuations.

(:-})

[benny hedges]

choke cable might be moving free but it sounds very much like one or both of the choke plungers is sticking inside the carbs.
airbox off jobby

[Steve6088]

choke cable might be moving free but it sounds very much like one or both of the choke plungers is sticking inside the carbs.
airbox off jobby

How do I go about freeing off the plungers? I've had the airbox off already but couldt work out what the choke cables were doing

Start with cleaning/changing the air filter if it's that bad as this will upset the mixture. It's probably worth doing a carb sync as well as these are all easily done. At the same time you may as well lube the choke cable just in case it's sticking and while you at it also do the throttle cables.

What set up have you got? has any carb work been done before, jets, tps, air filter change. As for the revs used to drop back down, don't forget carbs will fluctuate throughout the year due to use, temperature and humidity changes.

If any of these don't resolve it then your going to have to dig a bit deeper and maybe take the carbs off, strip down and clean. You should be able to have the bike idling at 1000-1200 rpm with no fluctuations.

(:-})

Everything is standard. I'll try getting a mechanic to sync the carbs after christmas. Reading AMCQ's guide on here, it sounds like too much of a complicated job for myself.

[benny hedges]

choke cable might be moving free but it sounds very much like one or both of the choke plungers is sticking inside the carbs.
airbox off jobby

How do I go about freeing off the plungers? I've had the airbox off already but couldt work out what the choke cables were doing
.

just follow the choke cables and they lead to iirc a black 12mm plastic(?) nut towards the back of the carb.
the rear cyl choke plunger is close to the tps - you'll find the other easy enough - its on the same side but toward the front of the carb assy.
undo it Carefully lol!!!

pull each out and give it a good clean, and the hole it goes in.
a very light smear of grease or vaseline will help but dont overdo it or you could block the air bleed holes!


this problem could also be a split diaphragm but theyre an butt to do.... check the choke plungers first cos you dont need to take the carbs off to do that

[VTRDark]

How do I go about freeing off the plungers? I've had the airbox off already but couldt work out what the choke cables were doing

You could do them with the carbs in place but it's fiddly and the plastic thread connectors are very fragile. IMO it's easier with the carbs removed especially as the connectors are fragile. If the airbox is off it's not much more work to remove them. Simples.

On the side of the carbs you will see one cable goes into each carb. Note the rear cable goes torwards the rear and over the top of the carb. Undo IIRC the 10mm (scratching head) or is it 8mm nut on the end. Try to do this as slowly and square on as you can. The plastic thread can damage easily. Once these are removed you will see the plungers. Your best bet is to undo the choke at it's mounting point and feed back through between the water hoses, undo the plastic bolts/connectors at the carb end, and remove completely so you can get some lubrication down the cables and a light smear of grease on the plungers. Don't overtighten the plastic connectors when putting back on There are many that have snapped them. One more thing. It helps to pop the rubber bit off where the elbow is, then it makes it easier to turn the bolt around.



For complete carb removal http://www.vtr1000.org/phpBB3/viewtopic ... 22#p223894

(:-})

[NHSH]

+1 from what it sounds like, that would be the problem, you got a complete advice from Benny and Carl, great detailed explanation

[Steve6088]

Cheers cybercarl and Benny

Your suggestions were spot on. One of the choke cables was sticking out and not returning back. Replacing the choke cable with a spare cable I have has fixed it . I had to take the carbs off in the end to do it.

[NHSH]

The greatness of the forum ;)

[benny hedges]

Fetch it round mine if you need the carbs balancing stevo