ONGOING RS125 PROBLEMS!

stirlinggaz · World Chat Champion Joined: 22 Jul 2007 Karma :

Hi all,
as some of you are probably bored of hearing, i have been having a few problems setting up my Aprilia rs125!
story so far - took it off the road a few months ago.
shortly after buying it, as it was very noisy & i had problems starting it.
so,
took it all apart,
put a twin exhaust on,
put the proper air box back on etc
anyway, now time to put back on road,
but had trouble starting it,
new plug solved that,
was getting very hot, bled coolant again today,
seems to have solved that!
next problem - last week i tried it with standard carb & was getting up to speed & idling ok,
just getting very hot.
today i put 34mm carb on, with 160 main jet,
started ok,
decided that i would gamble on oil pump being ok!
cos plenty smoke coming out of exhaust!
but it doesnt want to idle, having to keep revving it, or it cuts out,
turning idle screw seems to make no difference?
and also hitting a flat spot at about 30mph which i cant get thru?
if i didnt know better i would say it was the cdi bridge needing cut - but this has been done, so must be a carb issue, right?
so what should i do?
persevere with 34mm carb & try & get it running right?
or stick standard carb back on & change jet accordingly?
& see how it runs & chuck bigger carb away,
anyone any suggestions?
i feel like im 95% there, to getting it back on the road.
HELP!
cheers,
GAZ

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Personally I would say start with it stock and work from there.

The idle adjuster should make a large difference. Are you sure you are not turning the idle mixture adjustment?

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

stirlinggaz · World Chat Champion Joined: 22 Jul 2007 Karma :

hi,
as far im aware,
idle adjustment screw is bigger screw, on side of carb. its spring loaded.
& the mixture scew is the little screw further down & to the left.(a lot smaller)
its a vhsb 34 if that helps.
looking for a decent pic/diagram if anyone can help!
ok,
so time to swap manfolds/carbs & start again!
doesnt take me long now, done it so many times, im getting quite fast!
cheers,
GAZ

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Idle speed screw is the one smack in the middle of the slide.

As I say, try returning it to standard (and that includes checking the reed valves are OK, compression OK, no exhaust leaks, carb back to standard, ignition timing OK, etc) and work from there.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

stirlinggaz · World Chat Champion Joined: 22 Jul 2007 Karma :

stirlinggaz · World Chat Champion Joined: 22 Jul 2007 Karma :

Hi all,
just swapped over carb/manfold,
bike starts ok,
idles ok once warmed up,
gets up to speed ok, better than yesterday!
couldnt really test it cos roads are very icy, no sign of gritters!
dunno if powervalve is working correctly, test that when its a bit less icy!
just ran it with an aftermarket conical air filter as a temp measure,
but once i have fitted a bigger main jet, either a 128 or 130 & fitted air box back on,
bike should be a goer!
perhaps its time to give up on the 34mm carb!
finally feel like im getting somewhere!
thanks for all the advice, you know who you are!
cheer,
GAZ