150d vibration

[Abbo]

Hi all just after some idea of where to look next , I've got a 56 150 d which has always had a bad engine vibration at Higher revs. it happens in every gear and in third the vibration comes in at about 35 mph , I have rebuilt the engine as it had very bad whine and have fitted some upgrades as follows- new crank , varitronic system , alloy barrel kit , new bearings etc . on reassembly I checked the fly wheel run out and this was true and also checked the clutch basket and this was also true. The engine whine has disappeared but the vibration is still there. As I've only ever ridden series 3's are these engines prone to vibrating ? Or has anybody come across this and managed to fix it .
Many thanks

[missing lynx]

my ld was the smoothest lambretta I've ever ridden does it vibrate when at a stand still or only when it's moving? also did it vibrate before you did all the engine work?

[Abbo]

It vibrates when revved in neutral and did before all the work

[Scooter Paul]

Have you tried it without the engine cowlings fitted? Could it be this or is the vibration deeper in the engine as in something running out of true?

[Abbo]

Definitely deep in the engine , I'm using a bsa cylinder head so I'm running with no cowlings at the present , apart from the crank and clutch bell I can't think of anything with enough mass to vibrate this badly , I also changed the engine mounts but still the same. I thought If there was a problem with piston weight then every owner with the alloy kit would complain of this .

[Rob Miller]

If you are using a higher compression cylinder head, this will increase vibration. My D has a squish head and it does vibrate. Don't forget the D doesn't have all that heavy bodywork to dampen vibration that the LD has.

[Abbo]

The engine was vibrating in its standard set up, how bad is your vibration ? I was thinking of fitting bar end weights to lessen have numbness in my fingers!

[Rob Miller]

Yes I have been considering the same solution, but having ridden it for over 500 miles on the Derbyshire 150 weekend I think I can live with the vibration white finger.