Won;t run without choke

hello all new to this, I have a DB Motors Pirat 50 running a Morini S6s
50cc 2 stroke engine, it's a kids race bike. Till now I have managed to
sort all problems it;s thrown my way. Basically the bike runs fine on
the choke revs all the way out to about 14500 and 11bhp..but take the
choke off and it won;t run past idle if it runs at all.
I have so far changed the plug, drained and replaced fuel, stripped the
carb and also cleaned the air filter. Nothing seems to have worked.
Any suggestions?
thanks in advance for any help offered.

 

Sounds like either too much air or not enough petrol. Check
for air leaks in the seals around the airbox to carb and carb
to engine. If it's not that it sounds like you need to use
bigger jets in the carbs.

Have you done any work on the engine (porting/new exhaust/
filters/etc) without setting up the fuelling? This could
throw out the air/fuel mix.

 

Are you absolutely sure that you have the choke in the right position? It
sounds like you might have it the wrong way round - runs fine in one
position (= choke off?) bogs in other position (= choke on?). If the choke
position IS correct then you either have an air leak or fuel starvation
(partially blocked jet in carb?).

Tony

 

Shot in the dark, here, but is there an idle-speed adjuster? If so, wind
it up a bit.

Just my £0.02 worth.
--
| Wik -UKRMHRC#10- 2003 R1150GSA -DC#1 -'FOT#0 'FOF #39 - BOD#12 BOB#12
|# You don't believe me | "Experience is the worst teacher.
|That the scenery | It always gives the test first
|Could be a cold-blooded killer. | and the instruction afterward."
***** human response from wik at blueyonder dot co dot uk *****

 

The chokes the right way, it's a pull up type choke not lever. No
possible way it's wrong way.
Have stripped carb out and no dirt found but cleaned it/blown jets thru
anyways. Think it may be air coming in somewhere weakening the mixture.
Thanks for all advice given so far will post back when I find a
solution