22 replies to this topic

[68+86auto]

Connect the breather ports to the breathers. If it won't idle, adjust the mixture richer. Run it for a minute or so and then check the float bowl levels

[miniGTS]

Float bowls are both around half or just over half full. No more noticeable petrol leaking anywhere. It's running rich, I'm sure, with jets turned out 3.5mm from the bridge but it still sounds like it wants to choke off when I push the carb piston pin a small amount. I'm starting to think a single carb would have been sorted already...

[Lplus]

Float bowls are both around half or just over half full. No more noticeable petrol leaking anywhere. It's running rich, I'm sure, with jets turned out 3.5mm from the bridge but it still sounds like it wants to choke off when I push the carb piston pin a small amount. I'm starting to think a single carb would have been sorted already...

Define a small amount.  The correct lift is 0.8mm.  any more and the test becomes pointless.  what are the plugs like now?

[miniGTS]

0.8mm is hard to measure but I'm sure my small amount is more than that. The plugs are still black but I haven't taken it on the road today. It just dies now when I try to pull away in 1st. I'll try again tomorrow.

[miniGTS]

I wonder if I have an air leak in the inlet/carbs somewhere. So the revs fluctuate quite randomly, could that be out of balance or more likely an air leak or something else?

I've leaned out the jets a bit and turned the idle screws in a bit and got it idling at around 1500 rpm assuming the tacho is somewhat accurate but even there it seems to dip to 1200 then go up. Below 1000 rpm sounds like it just wants to die

[miniGTS]

Adjusted the jets to 2 and half turns out which is around 1.7mm from the bridge and it's running considerably better at idle. I'll take it for a short drive tomorrow and see how it goes. I think it's adjusted much better than before but still needs to be balanced properly. It's idling at around 1000rpm now according to the tacho which may or may not be accurate.

[miniGTS]

But today, it won't run steady when trying to start cold pwith choke out. Revs go high then drop and dies...

[sonscar]

Fast idle screw adjustment?Twins really need balancing accurately,both at idle and on the throttle.Mixture needs to be equally set.Both chokes need to be equal.The adjusters are primitive and need care when setting and checking afterwards.Near enough may not be good enough.Just my experiences with twin SU.Steve..