Jerky feeling at 60mph

[NeilwithYellowVTR]

Hi guys, just wondered if anyone knows what a likely cause is of a problem I've been having with my VTR lately.

Bought it a couple months back and never test rode it at speed.
But what i've noticed is that at speeds of around 60mph it gets a little jerky - almost feels like the petrol is trying to splash out of the tank..it seems pretty fine above 70 but in-between it seems pretty jerky at times. Doesn't happen all the time but often.

Grateful for any assistance, I'm a total mechanics newbie.
Cheers

[MacV2]

Hi guys, just wondered if anyone knows what a likely cause is of a problem I've been having with my VTR lately.

Bought it a couple months back and never test rode it at speed.
But what i've noticed is that at speeds of around 60mph it gets a little jerky - almost feels like the petrol is trying to splash out of the tank..it seems pretty fine above 70 but in-between it seems pretty jerky at times. Doesn't happen all the time but often.

Grateful for any assistance, I'm a total mechanics newbie.
Cheers

Carb fart...do you get a kinda clunk felt through the tank...Quite a commom trait, big carbs...big carb farts...

[NeilwithYellowVTR]

Yes I do. |Is it normal? Fixable?
Cheers

[MacV2]

Yes I do. |Is it normal? Fixable?
Cheers

Well you could get it on a dyno & see if they can tune out the issue but as the VTR carbs are the biggest ever fitted to a road bike, there has to be some compromise some where...have a read through this... viewtopic.php?f=31&t=28922

& this... viewtopic.php?f=31&t=18430

& this...viewtopic.php?f=31&t=29429

& this... if running different pipes & jets... viewtopic.php?f=31&t=14214

It's a complex old thing this carb malarky...

[NeilwithYellowVTR]

Thankyou Mac Ill have a good read..

[Chris58]

Thankyou Mac Ill have a good read..

Good Info there for sure.

usually carb maintenence will help with things like this.

Also very easy to check the slides are operating properly if you have it apart. Just take off airbox lid and use your fingers to move slides up and release together. If one is sticking then it wont give the proper mixture in the mid range.

hope this helps

cheers

[NeilwithYellowVTR]

Cheers Chris ill investigate!

[Stratman]

Having owned my VTR for 18 years, I can honestly say that I have never experienced the carb blowback etc. IMHO, if everything is standard and clean/synchronised etc then it will run perfectly smoothly at all revs. My idle speed is around 900, not the 1200 that some recommend as that is too high in tight turns off the throttle without slipping the clutch.
Before paying out to go on a dyno, check that all is standard and in good fettle then start from there.