Fuel supply pipes to carbs & sticky throttle

[Styler4077]

Hi all,
Trying to trace a stutter when running at a constant throttle.
30mph or 40mph or what ever I'm getting a hesitation and the engine kind of hunts.
So I've taken the tank off tonight, checked all the rubber tubes and they all look good.
Check for kinks (none) just like me
The large pipe on the offside from fuel tank to carb I can blow down but the nearside one seams blocked.

Is that right? Can't think it can be.. Or should I at least hear a hiss?

Second question is in regards to a sticky throttle, it's just slow to return and I can't see why.
Cables look ok, spraying cleaner on the near side spring and am just trying WD40 on the off side spring.
Any one fixed this by spraying?

Cheers

Styler4077

[darkember]

Has the bike been standing for any period of time with the old fuel left in the carbs & tank. The fuel can go off & get gluey. First check you dont have any vacuum leaks. If thats ok then remove the carbs & strip & clean. Remember do one at a time so you dont mix the bits up. To lube the throttle cables its best to remove them off the carb end, dangle them down, then open the twist grip assembly & pour in some thick oil like heavy gear oil & allow it to flow till it drips out the lower ends. Note WD40 is a moisture removal product you will need to lubricate after using it.

[Styler4077]

Don't have time for a strip down as there is a local charity bike show I'm leading a run to tomorrow.
Just mucking about in the garage for an hour or two before bed.

Sticky throttle fixed by flushing cables with WD40 after removing the top of the throttle housing on the handle bar. Will flush again at work during lunch time with some thin oil down the cable as per my WD40 flush.

Will treat her to a fresh tank and some reddex fuel system cleaner on the way to work tomorrow.

Any idea if you should be able to blow down both tubes to the carbs or neither?

Cheers for the reply in any case.

Stephen

[VTRDark]

Trying to trace a stutter when running at a constant throttle.
30mph or 40mph

What revs are you at here. Sounds like a bit of a lean surge maybe.

I'm not sure if blowing down the tubes will help much. You could easily pull the pipe off at the carb end. But if any crap has got in there then you will need to strip the carbs down and give it all a blast through with some carb cleaner or airline. It's only hours work max, and that's putting it all back together as well.

Stick a dollop of grease in the cap at the throttle end and this work it's way into the cables over time and keep things sweet.

(:-})

[Hairy biker]

Any idea if you should be able to blow down both tubes to the carbs or neither?

Cheers for the reply in any case.

Stephen

You will only be able to blow down them if the float needle is open to allow fuel into the carb so it's not nessasarily a problem if one is easier to blow down than the other,unless the float needle is knackered of course and its not allowing fuel into the carb, unlikely but anything is possible

[Styler4077]

Did a run before I can home and it's at a constant throttle between 30ish and any other speed, but only when you are on minimum throttle.
Could be lean but I've not changed the air filter nor the jets and needles.
(I have a Pipercross and Dynojet but can not be bothered even on my dyno)

On acceleration there is no hesitation, at higher rpm in lower gear (30mph) it's just the same a higher gear and lower reves (50mph)
Gotta be some thing blocked on the carbs as its the same hesitation at steady reves and small throttle opening.

Will strip them down and check all the rubber hoses to the carbs along with the carb engine rubber mounts.

Not sure if it's popping and farting more on over run than it ever did, if it is then I could have an air leak.

Thanks for the replys.

Stephen

[flynavyj]

My bike had had an issue where the revs would hang up as engine speed decreased with the clutch in, or in neutral. The hangup was always around the 2k RPM area, and I think it's fuel related...I had also noticed that I had a sticky throttle that was slow to close (but it still closed). My bike had aftermarket bar ends on it, so I thought to take a look at the throttle side unit. What I discovered was that the throttle side bar end weight didn't have enough washers in to space it far enough from the throttle tube...end result was the throttle would hang up when you'd let off the gas...I'm pretty certain however that this is separate from my rev hang up, but was an easy/free fix for a sticky throttle...simply utilized an slightly thicker washer to replace one already installed.

[VTRDark]

You bring up a good point there flynavi. The end of the rubber grip or throttle tube can sometimes rub against the inside of the bar end weight which stops the throttle tube returning. This is usually caused either because the grip has not been slid down the tube far enough or the there is damage to either the end of the bar or the internal weight inside the bar.

As for your revs dropping you will find that setting the TPS on the side of the carbs to 500 ohms and balancing the carbs will help with this issue.
http://www.vtr1000.org/phpBB3/viewtopic ... or#p222504

This will require carb removal.
http://www.vtr1000.org/phpBB3/viewtopic ... al#p223894
Please Note you have the PAIR system on your bike which is not mentioned in the above link.

Or follow the instructions for carb removal in the MCCT guide in my signature.

(:-})