rapido 225 with a jetex 22mm...?

[byron]

is this carb just too small for the kit ?
having problems getting it to run ok above ½ thotttle, better with the choke on, but just seems like it wants more fuel than the carb can deliver...
some other problems on this bike [with crank, now fixed] may have have been masking the poor performance, plus it may never have been riddne hard anyway...
I have got a PHBH 30 I could try... but I'm guessing the owner would rather not spend any more than he already has...
so interested in carb spec if if anyone has a 22mm [through a camlam filter] that works ok with this top end [and a scootrs pipe]...
thanks

[Adam_Winstone]

I and many others have found that 200 atomisers will flood out mid range and higher, resulting in the need to use a weaker atomiser and MUCH BIGGER main jet, which keeps things clean at half and correct higher. If you try fitting the correct main that your motor wants, the 200 atomisers just stop it dead at 1/2 throttle and don't let you progress to the higher range. What is interesting is how air box modifications (still retaining a standard filter) can result in the big increase in main requirement. With some of the high-flow filters now available it is quite possible that the 22 (or reamed 24.5mm) could flow enough for many of our road ported motors to be quite happy to run on, whilst looking and sounding like a standard'ish bike.

I've commonly used Italian spec' GP150 atomisers and once (perhaps twice?) used LI150 atomisers and a big main to release the potential of bigger cc/tuned iron barrels. I am also aware of completely standard SIL IVs coming back from UK dyno sessions using the Dellorto GP150 atomiser, and an iron 225 using te same atomiser after a dyno session with another top dyno centre... both used bigger than standard mains although the standard SIL IV was still only 123-125 with standard airbox and standard clubman.

Adam

[byron]

thanks Adam
useful information
I shall try some different atomisers

[byron]

Adam, you're a star
once again, your knowledge & experience has provided the solution
put a #4 atomiser in, and it was transormed; perfectly rideable now.
cheers

[Adam_Winstone]

Adam, you're a star
once again, your knowledge & experience has provided the solution
put a #4 atomiser in, and it was transormed; perfectly rideable now.
cheers

Too many hours of my life spent messing about with mopeds.... well, that's what my family says!

Do make sure that you spend time making sure that the overlap of progression stages is ok with the main that you opt to run. Testing is the key to getting this right and keeping both you and your motor safe.

"transformed", a good word for describing just how dramatic a change this can make

Glad to help.

Adam