View Full Version : Starting problems - Moto 6.5

09-27-2002, 10:24 AM
Anyone help with cold-start problems on my Moto 6.5? This model has the same Rotax 650 single motor as the Pegaso.

Cold start has always been a full-choke, no-throttle exercise, the motor slowly fires up. Now it will not fire on full choke, can smell petrol, so switch choke off and s-l-o-w-l-y the motor eventually gets going. New plug - no improvement. No obvious signs of carb trouble, all looks OK.

Is this normal for the Rotax engine? Any help appreciated as it goes so well when it's warm.....

micah apriliaforum com
09-27-2002, 10:57 AM
Use the performance model of the ignition timing resistor, set idle mixture screws about 1/2 turn richer (further out). Problems should go away quickly. For more tech search the Pegaso forum as this has been an ongoing issue with many good threads. The Moto 6.5 is a pretty cool street ride, I saw a lot of them in Amsterdam and Barcelona...

09-27-2002, 11:43 AM
...for the rapid, relevant and interesting response

09-29-2002, 08:13 AM
On checking, the resistor is the correct one (10k ohm) and the carb (Mikuni BST40) does not seem to have any adjuster screws, apart from the throttle stop.

Any further suggestions very gratefully received as the bike continues to be a pig to start when cold, and the local garages are less than helpful.


micah apriliaforum com
09-30-2002, 09:50 AM
The idle mixture srews may be hidden underneath little aluminum caps...which you must drill out. They are normally located at the underside rear of the carb at the point where the carb joins the manifold.

10-01-2002, 05:36 AM
..for the detailed info. I'll investigate and drill carefully!

All the best,

10-01-2002, 05:52 AM
...problem now solved. Half a turn makes all the difference, and the screw was exactly where you described (without a cover). Just need "midwives fingers" to adjust it!
Thanks again..

micah apriliaforum com
10-01-2002, 08:57 AM
There is actually a special tool for adjusting the carb mixture screws....but the easy way is just to remove the carbs and adjust them on the bench....usually one half turn further out is all that is needed.

10-28-2002, 07:30 AM
In case you pick this up - thanks very much for the tip you gave me, the simple carb adjustment has made the bike very much more useable, now it is a friendly creature at low, pottering-about, speeds - absolutley vital for a town machine. Spot-on.

micah apriliaforum com
10-28-2002, 12:12 PM
Glad to hear all is well.

Jamie p
04-22-2019, 01:19 PM
Hi i was wondering whee the cdi is located on a aprilla sr 50 ditech racing?