[Arizoni]

Sorry about your Z4.
The UCE has hydraulic valve lifters and if there is a problem with them it will be so loud that any normal person would be afraid to even sit on their bike.

I am trying to figure out why my G5's engine is so quiet in the morning when I start it.

While it's about 50 degrees F in the morning and idling it does not have any tapping, ticking or knocking sound at all.  Just the chug chug chug of the exhaust.

When it gets warmed up all of the good old summertime sounds return. 

[Desi Bike]

Oil thins out when it gets warmed up. What ever is causing the summertime banging is something with a very small clearance, thick cold start oil fills the gap.

[ROVERMAN]

I don't have a UCE Enfield but, i can tell you that the clattering noise that seems to be attributed to the lifters is more than likely a design flaw. When i worked on Mazda s back in the eighties we started using "hydraulic lash adjusters" on most of our engines. The Mx5 4 cylinder used inverted buckets and were relatively trouble free, as was most everything on that car. But the "finger" style lifters used in the V6 and larger fours were a nightmare. We had several updates and service bulletins on the death clack from hell but they never fully cured the problem until the engines were superseded by another design.
 One important thing was that despite the noise emanating from under the hoods of these vehicles i never heard of any damage or engine failures as a result of the noisy lifters. Hopefully the factory are aware and will respond with some real action in the future.
Robert & REnfield.   

[Maturin]

I´m constantly wonderig why there isn´t any damages reported by folks who´s engines are clattering. It´s occuring quite often, but there is not power loss, no oil consumption, no bad habits happening as a follower of the noise. Very odd indeed.
Did anyone had a look inside a cylinder head of a clunker?

[aziai79]

I just went in for my first service (at 500 miles, which is what dealer recommended) and let them know about engine clattering sound on my g5 deluxe, which seems to be most noticeable at mid to high rpms of 2nd gear and low to mid rpms of 3rd gear. like other RE owners, noise does not affect performance, but is annoying as hell on any bike, much less a new one.

When I went to pick the bike up, dealer stated that they think they fixed the problem and that it was due to the heat shield being loose. turned bike on and rode off, and while bike definitely ran smoother after servicing, clattering noise was unfortunately still there.

[bebopper]

  This has been mentioned before, but when the top end is disassembled, the right cover removed, and all the gunk blown out of the oil lines, the clatter has disappeared.

[Maturin]

  This has been mentioned before, but when the top end is disassembled, the right cover removed, and all the gunk blown out of the oil lines, the clatter has disappeared.

There are a couple of postings mentioning this phenomenon. However, it would indicate that oil lines are fully or partly blocked by gunk, reducing the head´s oil suply. This could even hamper the oil circuit as a whole, but at least it would jumble oil pressure.
But several mules actually do run clattering for quite a while now, mine clatters for 10´kms and I doubt it would have done that with a blocked oil line. I´d like to mention that I, sometimes, have a lot of fun opening up the throttle. Lot of fun, indeed.
I´m not sure if this could be the reason for the noise.

[Arizoni]

bebopper:  Which oil lines?  The drilled passage that runs from the crankcase up to the cylinder head, the one that connects the hydraulic valve lifters to the passage I just mentioned, or both?

[bebopper]

  Both. The oil port between the cover and block just below a bolt tends to get plugged by sealant, and that can go into the head. This is after the filter. Scooter Bob has advised to use nothing but grease and I found that works quite well; no seeping with hard riding and there was seeping with sealant. Also, you can reuse the gasket since there's nothing to remove from either the gasket or the metal. Everything stays cleaner. But hey, what does Scooter Bob know!!