H2C Idle - over run?

[Nigel Thorpe]

Hi. Just got one of the H2C's going after some work - carbs etc. Starts fine and idles OK. If I push the revs up to 2500 or 3000, then let go, it takes 15 seconds or so for the revs to drop back down to the idle. Would anyone have an idea why please? Thanks. Nigel

[Wolfie]

Have the Carbs been balanced as per the manual? It may be that just one is pulling the others along.

On my own, I found that lowering the tickover just a little helped it drop quickly back down although there is still just a slight delay.

[Nigel Thorpe]

Hi wolfie. Sent the carbs off to tangoman, who went through them. Set all of the slides even when off the bike and marked the knurled throttle stop screws so I could increase/decrease the tickover evenly over the carbs. With carbs back on the bike, set the throttle cables to sychronize the slides opening. Air screws are 13/4 turns out. The choke cables, or should i say 'fuel enrichment', were each adjusted at the carb to give approx 2mm of slack with the valve closed. Idle is around 1500 at present so will try reducing it when i next run the bike. I wonder if a sticking 'choke' valve may cause the overrun - if it isn't closing properly.

[TallyB]

Maybe oil the throttle cable as the bike has been sitting a while.