solo 2350 engines

Hello people,

I have a Ventus CM Self launcher, I was having starting proplems, so we
checked the plugs and the gaps and changed the airfilters.

The filters supplied were two piece and came off because they were two
piece and since that time I have had a loss of revs.

The battery has been replaced and now the engine starts really well all
the time but I still have a problem with loss of revs.

We have since put the old airfilters back on, cleaned them and also
changed the mixture setting.

Running the engine with airfilters off helped in prove the revs, to
6300 but not fully to 6400, and now is only getting 6300/6200.

It has been suggested any rubber from the airfilters that may have
fallen in the carbby would have been burnt up straight away.

While I am at the moment getting a good climb at 6200/6300 I would be a
lot happier if I started off with the 6400 I should have.

Any Ideas about what could be causing the loss of revs.

I have ordered new airfilters, the right ones

Rob