jerky pig

Hi lads

Virgin poster here ... and clearly a virgin mechanic too!

When I ease off the throttle a bit, to slow down, and then pick it up softly, the pig jerks hard. This is terribly annoying in city traffic, and also makes it very hard to go smooth, without fiddling the clutch all the time. I've had the carb cleaned, the gas cable lubricated and adjusted, and also the clutch changed, but the issue is still there. Any idea what I can do to resolve this annoyance?

It actually went away after I hadn't driven it for about 4 months, and I really enjoyed a very smooth 100km or so, and then it returned ... odd!

Surely it must be something with the carb? It's all stock, by the way, except for the uncorking parts ...

Thanks a million!

You sure its not your gearing ?, mine was terrible when I got her with SuperMoto wheels on and road sprockets, was really lumpy around town and terrbile to ride, as soon as I went to off-road wheels and 13~53 gearing she was smooth as silk.

Mauser wrote:You sure its not your gearing ?, mine was terrible when I got her with SuperMoto wheels on and road sprockets, was really lumpy around town and terrbile to ride, as soon as I went to off-road wheels and 13~53 gearing she was smooth as silk.

Thanks, Mauser! Hmm, you could be right, but that doesn't explain the ultra smooth ride I had after she had been standing still for months. The previous owner did gear it for better highway performance ... I will have a look at the numbers and post them. What's the original gearing?

It feels really annoying, especially in turns, where ultimately you would like to throttle down, and then pick it up out of the corner, but the jerk is so hard, I'm afraid it will cause the tire to loose grip ...

Stock Gearing 14/48.....   

No rear hub cush drive means they do jerk a bit like this, only ever really notice on road rides.

Maybe it was ok after you didn't ride it for a while simply as you were taking it extra easy (as you hadn't ridden it in a bit)?

Recheck the throttle cable - mine if "clean" but after a load of dust it needs a bit of TLC... Is the cable alignment ok, not tight, no pinch points?

Your problem might not be the same as mine but i have had iddling and smoothness problems with the XR , tryed all sorts and in the end bought the mikuni TM40 carburettor , this have solved my problem and totaly changed the bike , i could not believe that i am riding the same machine it was so different - MUCH better .  

Tsk nowt wrong with the stock carb...mines smooth al low speeds and pulls away in any gear from stationary without missing a beat !!!!

That is correct , some stock carbs are working fine . From what i have heard i am asuming that they do wear quite fast and once the carb is worn the problems will start , big number of XR's have new carb instaled ( tm40 , FCR , Edelbrock, the most common ) so there clearly is something wrong with the stocker . I have spend some money trying to fix the problematic carb , wish i did not waste any and just went for the pumper , if i only knew then what i know now   . In your case Mausie its down to very low usage , if you dont ride it it will not wear   

How is your chain and chain adjustment?

TJE,
sounds to me your idling jet is clogged. Clean carb & install an inline fuel filter, and maybe wash tank too.

Fruity I may have XR650R OCD syndrome, but I do ride my bike when it's dry   but I must confess to cleaning inside the mudguards now and spending time cleaning the fork boots till they shine....I jest you not lol

mines the same and the most annoying thing about the bike...I tried all sorts of things including the suggestions above but nothing made any difference.  Kinda got used to it now.  Hopefully at some point in the future will change the carb but until then....

I have to admitt that my front fork gators are clean , i was suprised how much dirt was inside them i was the first person to clean them by the looks of it   

i found mine was a little jerky down low but fixed it with a leaner main jet.
Wonder if its worthwhile either adjusting your needle (leaner one clip) and trying it or try a main jet swap?
the first one is free, 2nd option will cost you a main.

just my thoughts..

Also check you have the 68S pilot in too, made mine much better.

As was also mentioned check your chain tension too as this can have a similar effect.

not just jerky low down - it isn't dependent on revs, just the action of rolling off and then on again.  I don't believe it is a jetting issue, sure it is mechanical but no idea what else to check.  maybe its just a 'characteristic' of the bike.  
Anyone in Kent in the UK that would let me have a spin round the block to get a feel of someone else's bike?  I know Hew would but I wont be up that way next time I am back in the UK.

Cheers
SkidMark

I'm in the midlands Mark so a bit to far away

Oh, I already know what (ALL!) you guys do - whack it open from closed!
Get a Mikuni TM40, a pumper, it won't be 'jerky' at all.

I am in the North east area Mark if you happen to drive around here   

BuRP wrote:Oh, I already know what (ALL!) you guys do - whack it open from closed!
Get a Mikuni TM40, a pumper, it won't be 'jerky' at all.

Cough , cough .... All ?   

ALL that have jerky symptoms Maddy, the std carb simply is not for whacking open. Nothing wrong with it but it want to be rolled open, not treated like a switch.

Am not whacking it open - rolling it on as gentle as possible and it still jerks...

Well my little my-kuni runs smooth like a butter   

Mad Frosty wrote:Well my little my-kuni runs smooth like a butter   

Still got the standard carb stashed away somewhere...?

SkidMark wrote:

Mad Frosty wrote:Well my little my-kuni runs smooth like a butter   

Still got the standard carb stashed away somewhere...?

Oh scratch that just reread your earlier post.

have you checked the operation of the acl valve?