I have picked up some float valves to install this morning and the seller had a plausible theory on what might be happening. He thought the emulsion tubes or 'needle jets' might be worn and letting fuel get past on a closed throttle causing the flooding at high engine speeds.

Happens a lot on the old 900 Kwaka's apparently.

So my problem now is parts availability. I have seen the NSR carb kits on line from cruzinimage

Admin: eBay link removed as per forum policy.

but have my doubts on quality. Can anybody point me in the right direction for a supplier?

or Keihin parts list for the TA21a?