o2 yamaha ox66 150 low speed miss

[leadhead715]

)@ ox66 150 txrz has low speed miss between 1100- 1900 rpm. New filter in vst & main, New plugs, fuel pumps (vac) last season fresh fuel, compression equal all cyls. Over 2000 rpm no issues to 5200rpm. any ideas?

 

[leadhead715]

also noticed what sounds like vac leak by mechanical pump area. Any ideas I missed?

 

[leadhead715]

pulled both mechanical fuel pumps, both failed vac. leakdown test. Replaced and running good . Pumps only 10 months old. Yamaha factory parts.

 

[johnnygjr]

You wonder how they stay in business.