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[Thack]

My theory is that the lifters require more oil pressure than the UCE oil pump is able to deliver. This is almost certainly because the UCE has a roller big end, which is effectively "wide open" to oil and thus it's almost impossible to build up any significant amount of oil pressure in the system. I don't know this to be the case; it's simply a tentative idea based on the way the tappets seem slightly quieter when the oil is cold (and thus thick). I also note Deanobats' comment, which makes me even less certain about this!



Note: there is nothing wrong with the UCE's lubrication system. Apart from the tappets (maybe), it doesn't require any more pressure and in fact the oil flow is copious - no less than 9 litres per minute at 5500rpm. Compare that with the 2.4 litres/minute of the AVL, and the measly 1.2 litres/minute of the original engine.

[jefrs]

I have one of the new C5s. I wouldn't call the tappets noisy but they're certainly not quiet. Hydraulic tappets or not, it's a pushrod engine and you get a constant sewing machine chatter from it. It's regular and sounds happy, not loose and clattery. The noisy CGT may need the cam backlash eliminated, this is inside the case and a service job with oil; I think I read somewhere this is recommended for the EFi 1st main service ca 3,000 miles (not the 300 mile run-in service). As oil get hot it gets thinner, so you get a little more noise perhaps; the motor is air cooled.

[Rattlebattle]

I didn't know that the UCE engine has a roller big end, though I'm glad it has; roller bearings don't need much of an oil supply. Nobody else used to use the weird double bush big end - there's a reason for that.....The workshop manual clearly shows three separate oil feeds, one of which is to the hydraulic tappets. In this case, given roller bearings and valve gear won't need high quantities of oil to survive, I would have thought that there is plenty of pressure for the hydraulic tappets. In my experience they are usually noisier when cold because the oil has drained down, but the RE system is a bit different. You don't normally need to store the lifters upright to prevent oil drainage as the oil flow fills them up quickly when the bike starts - hence the rattle if you don't use the vehicle for a few days. FWIW my Classic is the only bike I have on which I don't wear earplugs - no need for a fruity exhaust pipe.

[Thack]

Rattlebattle writes: "In this case, given roller bearings and valve gear won't need high quantities of oil to survive, I would have thought that there is plenty of pressure for the hydraulic tappets."



You are right that they don't NEED much oil, but in this engine they get lots! I think you are suggesting that RE could have placed a restricter in the feed to the big end in order to develop a higher oil pressure for the tappets. I would agree, but they didn't, unfortunately.



As an aside, I'm not as much of a fan of roller big ends as you are. Nobody is suggesting going back to that floating bush thing, but most Japanese bike engines use plain big ends. The problem with roller big ends is that the relative speed between the conrod and the crankpin is not constant. It speeds up and slows down twice per crank revolution, so the roller bearing is constantly being forced to accelerate and decelerate. This can lead to skidding of the rollers, which is undesirable and leads to more rapid wear and failure.



Furthermore, when they do fail it is almost always catastrophic, with bits of bearing being liberated around the engine.



Putting aside racing engines, and just looking at engines that are designed to last well, how many car or bike engines have roller big ends?



I'm not saying roller big ends can't work. Of course they can! And when it comes to two-strokes they are your only choice. But they do have that theoretical shortcoming. So long as you keep the oil clean, a plain bearing can last almost forever. When they do wear, it is never sudden or catastrophic.

[jefrs]

Most of the initial start up clatter on the UCE will be the automatic decompressor, not the hydraulic tappets. The clicking noise that goes away after a few seconds. Push rods are always going to make some noise, running quietly it is a happy chutter, open the throttle and the exhaust barks. The push rod cams are down at the bottom and the backlash can be dialled out, reports from India indicate they can by noisy from new, not set up well.

[Rattlebattle]

Modern engines are built to much finer tolerances and are mostly liquid-cooled. They have proper oil filters (and often coolers too) to pump much higher quantities of oil round at high pressure, possible because modern construction and sealing methods allow this. Hence plain bearings rule becuase they need a supply of cool oil under pressure. But I doubt that the RE UCE tolerances are very tight or consistent, being hand assembled to a greater degree than most and the engines being air-cooled. Harleys use roller big ends too and they last well enough. Back in the days of British singles the vast majority of big singles ran roller big ends quite happily for many thousands of miles. There are thousands of these still on the road and despite the theoretical disadvantage of roller bearings I have NEVER heard of one wrecking an engine, on a road bike, because there is usually a warning before they destruct. BSA, Norton, Ariel, Velocette etc all used roller bearings and racked up huge mileages; only RE used the weird double bush. I don't believe that current RE technology regarding oil pump delivery and oil filtration is good enough to run plain big end bearings.

[Thack]

jefrs writes: "Most of the initial start up clatter on the UCE will be the automatic decompressor, not the hydraulic tappets."



Yes, but I don't think that is what the OP is asking about. I've removed the auto-decomp from mine.



"The push rod cams are down at the bottom and the backlash can be dialled out, reports from India indicate they can by noisy from new, not set up well."



I've heard that, too. On mine I've spent ages getting the lash to as close to zero as I possibly can without making the gears whine. Also I've spent ages shimming the cams to limit their endfloat, including grinding down the shims to achieve an endfloat of only 1 to 2 thou.



Unfortunately none of these adjustments made any difference to the noise.

[Thack]

Hey, Rattlebattle, don't think me rude, but have you owned many Brit bikes?



I ask because my experience of them is not as you describe: no way did many of them clock up "huge mileages" - people rarely did huge mileages in those days anyway. The modern trend of long distance touring on motorcycles was really quite rare back in the '50s and '60s. Even in the '70s, when I started riding, bikes almost never got anywhere near to clocking up mileages comparable to cars of that era. Lots got used for short journeys to work, and for modest leisure work.



Also, despite the rose-tinted glasses many people see the past through, Brit bikes were NOT reliable or durable! Especially not when compared with modern bikes and the very early Japanese bikes from that era. The main brands I and my mates owned were Norton, BSA, Triumph, AJS and Matchless. Trust me, they were crap! Compared to modern engines the mains and big ends were tiny - far too small to be durable or reliable. We were always blowing up and rebuilding the damn things.



The Norton Commando had so much whip in the crankshaft it would knacker the main bearings in a trice. They fixed it by fitting special bearings with barrel-shaped rollers (called "Superblend"). That is the quality of engineering we had to put up with!



Obviously we can all point to exceptions - bikes with bearings the size of cotton reels which still survived tens of thousands of miles. But they aren't representative of the everyday experience back then.



By the way, the fact that HD use roller big ends undermines my half-baked theory that the roller big end on the UCE prevents the necessary oil pressure from being built up for the hydraulic lifters, because I understand the lifters on our UCEs are an HD part anyway.

[jefrs]

I agree with Thack. I've been around british bikes since the late 60s. They make all sorts of weird noises. Get used to them and they'll tell you what's wrong. Imo my bike is chattering away making happy noises, all is working correctly as it should. I reckon the motor has run in and now the gear box is settling in nicely. Putting a roller on the big end does mean one good thing, that it's a roller is neither here nor there - they've redesigned the bottom end.

[papasmurf]

I have to agree with Thack, longevity was a rarity "back in the day."

Most British bikes from the 1960s still used and running have had a massive amount of internal re-engineering and modification, that can't been seen.