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[Deanobats]

Perhaps some of you can help with filling in some gaps in a conversation I had with the mechanic servicing my bike? I was having a front fork sorted under warranty (see the diatribe on 'pinch bolts' somewhere in the archive). Anyway, said fork was replaced, and the mechanic said that everything was fine, there was just a bit of a rattle in the engine. Now I've never noticed a rattle in the engine beyond what might be normally described as 'oh they just do that' or 'it's character', but as he mentioned it I started worrying. Initially he asked if I had "ever revved it from cold?" Now, I'm a sedate sort of person, and I don't recall ever revving it, from cold or indeed at any other temperature. He then continued "you know you've got hydraulic tappets?" I nodded wisely - this much I did know. "Well..." he continued "sometimes you get a little bit of oil in the xxxx..." Now at this point, I confess that my attention drifted. This was partly because I was trying to recall what I knew abut hydraulic tappets so that I didn't appear to be a total numpty, but mostly because a rather attractive young lady happened to be walking past at that precise moment wearing a skirt just the right side of decent. He continued "it's an easy job, you just remove the xxx cover and push hard down on the xxx and you'll see the oil come out and it'll be fine." Then he added "job's a good 'un" for good measure. I should of course have asked him to repeat it so that I actually knew what he was talking about, but my 'don't look like a total idiot' protection mechanism kicked in and I didn't. I just rode off with the rattle that I hadn't noticed before but which now worried me. If I had to specify what the rattle was, it seems to come from the general area of the rocker cover and to only be there when accelerating.

[nigelphoto]

Could I just ask is this a Watsonian era RE Dealer? They do tend to know what they are talking about but IMHO the recently appointed Dealers (post 2013) know naff all about Royal Enfields. They are probably a lot better with Hyosong, Ringadingdong, Twistandgoso and other Chinese scooters than motorcycles. I shouldn't worry about noises - for instance a lot of people get carried away with 'tappet noise' when its just the auto decompressor which makes a bit of a clacking sound at low revs.

[jefrs]

The only such adjustment on the EFI (with the hydraulic tappets) is the back-lash adjustment on the two cams that lift the pushrods. Hydraulic tappets are supposed to have oil in them. It would appear that you got the "added BS" explanation.



Doing the back-lash is relatively simple but does entail removing the RHS cover. The Workshop Manual does describe the job, albeit poorly. The manual is available online here and elsewhere (to 2010 models) http://www.midlandbullets.co.uk/pdf%20f ... 202010.pdf



I have not done the cam back-lash on mine as it sounds sweet (ok, that means a bit like a sewing machine) but it is listed as a routine service job. It looks like one to do with an oil change, only if it needs it.

There are dealers who know how to do a proper service. Whereabouts?

[jefrs]

Oops, the link looks corrupted



http://www.midlandbullets.co.uk/pdf%20f ... 202010.pdf

[Rattlebattle]

I'm with Nigelphoto on this one; I'm convinced my supplying dealer, though good at tuning bikes on a dyno, doesn't really understand the idiosyncrasies of RE bikes. I have no idea what your mechanic means; hydraulic tappets need to fill with oil. As far as I know you can't bleed them down and anyway that would increase, not decrease, the mechanical chatter. The question I would ask is whether or not YOU have noticed any increase in mechanical noise. If so, then that would need investigation. Although hydraulic valve lifters are supposed to quieten valve noise, in practice many have found them to be noisier than the adjustable pushrod variants. This could be manufacturing tolerances. Unlike some American motors the hydraulic lifters in RE depend on close tolerances and accurate assembly, up to a point, as there is no provision for adjustment beyond the limit of the lifter. By this I mean that some American motors with hydraulic lifters actually have adjustable pushrods too, to allow the hydraulic lifters to operate at their best. Without these it's all down to assembly and accuracy, which is why some rattle more than others. FWIW mine have always been very quiet, but some I've heard have been noisy. So, if yours have always been the same I'd just ignore the mechanic and have it serviced somewhere else, or do it yourself.

[Deanobats]

Thanks for that, I did wonder what he was on about to be honest as I knew there should be some oil in the tappets for it to work anyway. I can't say I've noticed anything unusual in the way of noise to be honest, it's always sounded a bit rattly but in a good 'it's working nicely' sort of way. It's only when someone points something out that you start to notice it. It's just about out of warranty now so I'm much happier about servicing the thing myself, that way I know that filters get changed if needed and the right sort of oil (at the right quantity) goes in.

[jefrs]

The word, "hydraulic" surely indicates there ought to be oil in a hydraulic tappet or lifter.



These things have been commonplace in car engines at least since the 90s. They are heavier than mechanical tappet adjusters, which probably accounts for some increased noise.



Squeezing the oil out will just result in it refilling. They're generally reliable and trouble free. When stuck hard by the push rod they go solid and open the valve, when the valve is closed and pressure from the push rod is removed they relax and draw more oil in to fill the gap. Like a shock absorber, you can push oil out by applying slow pressure; this happens if the gap between rocker and push rod becomes tight. In other words they maintain optimum tappet clearance.

[jefrs]

The cam back-lash adjustment won't alter the lift of the push rods. What it does is correct the valve timing, but it may also make operation quieter by removing some slack in the system.



One possible cause of excess top end noise is a loose head stay link/bracket. Another point of excess racket, the exhaust flange bolts might want attention. Both of these are of the self-loosening kind.

[Leon Novello]

Some car engines with hydraulic lifters, when started after a long rest, will rattle until the oil reaches them, advising not to rev the engine until the rattle goes away. This will be noticeable in motor oil commercials showing how fast their oils reach them. For the record, I didn`t know Enfield engines could be revved. DOH!

[Rattlebattle]

Yes, the old Ford CVH engine was prone to rattle on start-up if left a few days. REs don't really rev, they just gather speed......