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badboyshane
11-26-2013, 06:01 PM
http://www.apriliaforum.com/forums/images/misc/quote_icon.png Originally Posted by badboyshane
hi can you help us, ive just restored a rx for my son its got a standard engine de restricted a arrow exhaust new phbn16ns carb

our problems are it wont pull away up hill but when hits power band it flys, till you get to 6th and the revs drop right off
its also got a habit of going to a false neutral when it hits power band in 5th , i cant tell you the revs as its the Rx racing with the trial tech speed o

any help be much appreciated

regards Paul and Shane

Zav
11-26-2013, 06:38 PM
It's too highly geared aka sprockets

I have same bike and I had same problem except I got a 12mm carb so have less power but I endded up using 11/56 sprockets absolutely flys but only tops out at 50 mph but seeing as you have a bigger carb ild try 12/48 gearing see how it does if it still struggles and won't pull in 6th go to 11/48 and if that don't work you have a serious problem


Btw can I ask what main jet your using as I'm changing to a 16mm tomorrow and need a good idea of where to start

badboyshane
11-26-2013, 06:44 PM
hi yes thanks for your help we found the 105 the best jet , we putting an 11 front sprocket on tomorrow
thanks again

Zav
11-26-2013, 06:46 PM
Thank you

And it's okay and as for the false neutral it's a worn gear selector in the engines gearbox mine does same when I change from 5th to 6th

badboyshane
11-26-2013, 06:50 PM
yes jet fine 108 bogged loads and 102 she wouldnt pull
our bike goes in gear ok but when you hit power band in 5th it comes out of gear its fine in all other gears

apriliamandan
11-27-2013, 03:33 PM
Should have 120 main jet if you have a phbn16ns ​carb.

Zav
11-27-2013, 03:37 PM
I tried a 120 today and it ran like crap so put a 110 in was bit better and ended up at 108 that's with techngas exhaust and podfilter and is a perfect colour

The exhaust on the rx mx sx change the jet needed due to the exhaust on its own as the supermoto exhaust make less power than rs style exhaust that's why everyone who really tunes them uses rs exhaust and custom fits them

badboyshane
11-27-2013, 03:49 PM
bogged like hell with 110

badboyshane
11-27-2013, 03:51 PM
if we change to a 70cc BB can we keep the same carb

badboyshane
11-27-2013, 06:23 PM
if we chane to a 70cc will we get more low down power ie pulling away

badboyshane
11-28-2013, 02:16 PM
1st part done changed front sprocket alot better now i think it needs a new clutch as it only bites when lever is almost all the way out or is that normal

Zav
11-28-2013, 02:23 PM
Yeah you can keep same carb dans dad is running 2 am6 bikes on stickyparts 70cc kits and 16mm carbs and tecnigas exhausts and you will gain a bit of low down power if you get a mild kit

Use the adjuster on the clutch lever is the metal cycle just after the lever turn it out a bit

apriliamandan
11-28-2013, 04:42 PM
Yeah you can keep same carb dans dad is running 2 am6 bikes on stickyparts 70cc kits and 16mm carbs and tecnigas exhausts and you will gain a bit of low down power if you get a mild kit

Use the adjuster on the clutch lever is the metal cycle just after the lever turn it out a bit


Yup, way more low down power, enough to pull wheelies in first without too much effort. Can be in the 6th gear at 20mph and pull right to 60mph without any gear changes. Both kits are pulling 13:53 sprockets. Indicating around 65-70mph in good weather conditions. Both have been very reliable.

Im running a stickyparts 70cc (120) on my RS with stock crank, stock 16mm carb with just uprated clutch and race pipe. Performs great.

badboyshane
11-28-2013, 05:05 PM
thanks guys for you help

badboyshane
11-28-2013, 05:18 PM
is the polini sports race clutch and good

apriliamandan
11-29-2013, 01:48 PM
is the polini sports race clutch and good


One of the best. Personally, If you're getting a mild road 70cc kit, then I'd suggest you buy new stock clutch plates with uprated springs. Much less cost involved and will work fine.

RS_Patrick
11-29-2013, 03:54 PM
This should have gone in the Tech section...

badboyshane
11-30-2013, 12:27 PM
sorry Patrick we new to all this

badboyshane
11-30-2013, 07:21 PM
how do you adjust the mixer screw ours is fine except 1st it seems to bogg a little but ok once you change up

badboyshane
12-02-2013, 12:40 PM
just a thought my Rx has the trial tech speed o is it possible to fit cable speed o and rev counter like on the older modals

thanks all