Erratic tickover

[YorkieDave]

Just bought an NC21 off a mate which was used as a track bike.
Has stood idle for the last three years and I am putting it back on the road. Lights, indicators etc.
The problem is the tickover. Once the bike is warmed up (choke off) the tickover is all over the place.
I can set it with the throttle stop screw to a comfortable 1000rpm but every now and again it will race up to 3000 without me touching it. A good blip of the throttle brings it back down but sometimes it will then stall.
It also seems to take an age to return to tickover after a right good handfull of throttle (in neutral and on the stand) compared to inline 4s I've owned in the past.
Any thoughts???

[dobbslc]

Air leak on carbs somewhere.

[skinnydog0_0]

Yer likely carb leak, but I would get the carbs off and give them a very good clean as they are likely gummed up if the bike been stood for a few years.

[YorkieDave]

Thanks Guys

[Neosophist]

probably best to replace the rubbers as they will be so old.

[YorkieDave]

Assume you mean the seals between carbs and inlets?

[speedy231278]

Yup.

[YorkieDave]

Cheers

[Ben_OB1]

Also make sure your carb linkages are all well lubed, as they can bind and cause the carbs to lose sync and operate very erratically at tickover. Only requires a squirt with WD40. Made an amazing difference on my bike.

Ben.

[YorkieDave]

Cheers Ben