Setting up an SU

[Geoff Ryall-Harvey]

If you're having issues with your SU stumbling/leaning out on acceleration you can either buy a variety of new springs from Burlens (expensive) to try and see which one will slow the rise of the piston due to the vacuum created by WOT.... or buy a bunch of M33 stainless washers for less than a pound each and use them as dashpot weights fitted under the existing spring.

[david]

There is an excellent book by Des Hammill on tuning su's.lots of good ideas that work on tuning the needle to suite your engine..

[Geoff Ryall-Harvey]

I can thoroughly recommend that book - has a great section on how to select a needle to suit your particular application.

Unfortunately I lent it out and never saw it again....

You should only need to mess around with springs and dashpot weights AFTER you've got the right needle.