I have a 250 Rev three and the response (pick up) of off idle is very very soft.  It there anything that can be done to improve?  It does not feel weak in that it will pull tall gears at low revs but the engine just winds up very slowly.  A GG200 has significantly quicker response.

 

This is a 2008 with later 250 top end.  Timing is on the advanced side. I have run a 28 mm Keihin and 26 mm OKO and it is the same.  Jetting richer and leaner does not alter the response much.  I have also run Boysen dual stage reeds and OEM Beta reeds but it still feels the same. 

flywheelweight?

 

There is no flywheel weight. 

I am not 100% sure but I think that the ignition system on your model of Beta should advance quite a bit at just over tickover and then fall back at higher revs. Check the ignition advance by marking the flywheel and using a strobe.

Sometimes these ignitions fail by sticking at full retard (the starting setting) and if this happens it gives exactly the symptoms you describe. better to compare your bike with a known good Beta (no flywheel weight) than a GG.

Does it have the flywheel on the primary side? You can see it through the sight glass.

I don't understand the statment about a site glass.  This has the standard plastic cover over the flywheel.

 

I'll try it with a strobe.  If it is an advance problem, is it the CDI unit that is bad or could it be somthing else?

The site glass where you check the transmission fluid. Beta uses two different primary gears on the crankshaft. One has a flywheel integrated with the gear.

Near certain the timing advance electronics will be in the CDI unit.

 

As a general rule bikes with a timing trigger have any advance electronics in the CDI unit

 

Bikes that use the change of polarity in the source coil as the timing trigger either have no advance or at times have the advance electronics in the HT coil.

Yeah the CDI box has a uController in it. I've noticed the twin trigger coils which I assume is the engine speed sensor to set the advance.

My only Beta comparison is a 2014 Evo 300 Factory.  Throttle response is much much better on the 300. 

 

I'll try a timing light and see if there is any advance.  A CDI is $255 US so a bit expensive to try.

I ran a timing light on it and got a very odd result.  Idle is about 15 degrees BTDC.  Reving up the engine pushes this up to 20 degrees BTDC where is stays.  Could this mean the CDI is locked in full advance mode?  Does anyone know what this should be like?   

 

I have to run rich to avoid pinking when just creeping along.  I checked this a long time ago on a 97 Techno and got 6 degrees at idle, 20 at mid range and 25 to 30 at full scream.      

That's not a lot of range.