Gilera Runnewr VX jetting

Hi guys,

After managing to get the VX running and getting it through an MOT, i'm now riding theVX around and it's so much better than the old Speedfight i was on.

anyway next problem, now i'm not entirely sure what cc engine is in it but it's goes well, i'm guessing that it's not the 210cc engine that it was sold to me with having in it, anyway not that disappointed but i'm having issues with jerkiness...

if i slowly but progressively open the gas then the bike will pull ands take off fine but if i open the throttle fully from pull off i get full acceleration for about a second then the only way i can describe it is a jerk and then back to full power again, quite frightening in the snow and ice. (one it's done the jerk then it's fine all the way to 70mph+) so it's just a momentary jerk then off again.

I'm having a guess at it being the jetting in the carb.

what size jet would be reccomended for a 180 engine on a standard Walbro carb?
" 210 engine ?"

thanks in advance for the advice.

Oh and where would i jet a new main jet for a walbro carb?

 

I think hes looking at the fact that the engines been changed but the carb may be off a 125,

check the air box is tight and has no leaks. standard 200vxr main jet is 118

 

Thanks for the replies guys! :good:

As said the bike runsd a treat and runs smooth if i open it up from a standing start but it i slowly roll on the throttle and then open it up fully it then jerks (the only way i can explain it is like when you floor an automatic car it kicks down and changes gear - that kind of jerk) the clutch doesn't slip the revs dont rise abnormally just a momentary jerk and then it's off again.

I did buy the carb secondhand so maybe i'll strip that down at the weekend.
Also got some new rollers to go in, so i guess i'll do all that in one go.
will also do an oil change, check transmission oil and clean filter as this is the first week i've really run the bike since i got it (see other thread - http://www.scootershack.co.uk/viewtopic.php?f=6&t=17555)

cheers again lads. :mod:

 

Sounds like transmission problems, the main jet controls full throttle only.

Its likely to be your clutch, if you pull off at full throttle the clutch is gonna bite fairly hard. To be honist I remember my old VXR180 having this slight jerk. And they all make a little knocking sound when you come to a stop, the rollers knocking around.

If your that worried, have the clutch re-built or get a new clutch, get fresh rollers and a fresh belt, grease up torque drive, clean everything.