[AzCal Retred]

Has anyone here used the adjustable cam spindles to reduce their cam "backlash"?

Did you see significantly reduced timing chest noise as a result?

A post from Ace suggests there is no performance benefit, but I was wondering if it helped to tame the clatter a bit. I'm looking at replacing the guides soon, as there is noticeable side to side wear at the tappet head when unloaded. The cam spindles need to come out for this task anyway and it would only be a few bucks more. Any input?

[Adrian II]

The AVL/Electra-X models have these as stock items. I actually replaced them with fixed spindles as it's something else to work loose with the engine vibrations, which you don't want with the engine running. Also reducing the amount of slop/lash between the cam gears can just move it further up the timing gear train between the inlet cam wheel and the first idler gear heading towards the "distributor". That's not an issue on the AVLs with crank-mounted ignition.

You can experiment, but simply replacing any worn-out items as you suggest might be a better course of action. That valve train is ever going to be whisper quiet.

A.

[Adrian II]

Sorry, "that valve train is NEVER going to be whisper quiet". 

A.

[Paul W]

The valve train seems to produce the only noticeable mechanical noise on my 350 Electra, even though it has no distributor or drive gears. The last time I looked there was no slop or backlash anywhere and the tappets are set correctly so I think it is just a characteristic of the machine.

[cyrusb]

Tappets shall Tap. It's in their nature.
 But you can minimize the noise with a closer look at the way you adjust your tappets. Just like the older (and better) Harleys the "Just Free cold" pushrod feel is open to interpretation . Have you ever checked the adjustments after the mill was warmed up? If you do you may find that you can tighten up your cold adjustments a bit. With both the Harleys and the Enfield I have used this method to "Sneak Up" on a more accurate adjustment. Of course I check them more frequently but its worth it and it's easy.
 Also, when checking the adjustments try wiggling the tops of the tappets. My exhaust tappet is loose in its bore and is about half of the noise my mill makes. I have replacements but doubt I will ever install them.
 

[AzCal Retred]

Thanks CyrusB, the "loose-in-the-bore" tappet shaft is where most of the noise comes from on my machine too. I can move the heads a fair bit when they are unloaded & replicate the "rap" sound. The metal-on-metal pounding is RPM dependent, at road speed it seems to find a happy spot & quiet down, and is worst at idle. My cam noses seem to have a bit of wear also. Not a problem that money won't solve though, innit? 

I was wondering though if the adjustable spindles had any effect on total noise, seems like they might.

[cyrusb]

Thanks CyrusB, the "loose-in-the-bore" tappet shaft is where most of the noise comes from on my machine too. I can move the heads a fair bit when they are unloaded & replicate the "rap" sound. The metal-on-metal pounding is RPM dependent, at road speed it seems to find a happy spot & quiet down, and is worst at idle. My cam noses seem to have a bit of wear also. Not a problem that money won't solve though, innit? 

I was wondering though if the adjustable spindles had any effect on total noise, seems like they might.

Well, the gears would not be inclined to produce a tapping sound. Badly meshing gears would produce a whine or whir kinda sound. But since these gears are so lightly loaded (unless you run a mag) I would look elsewhere.  How you adjust the valves can make all the difference .
As an aside, There is so much oil collected down low in the timing chest that most cam gear noise would be muffled. To get back to the tank the returning oil has to make it all the way up to a 5/16" hole behind the last idler. That is a torturous path, with only gear windage and crankcase pressure to help it along.

[Paul W]

I watched Michael Walker’s video where he explained how the distributor idler pinions acted as an oil pump to return oil from the timing case to that return port to the tank. My Electra must rely only on gas pressure and gravity because it has no idler gears, the case is completely empty and redundant above the cams.

It all seems to work very adequately because when I recently took off the cylinder and looked inside the crankcase there was hardly any oil in there, so it certainly isn’t backing up. The oil level in the timing case might possibly sit higher than on some engines, but probably no matter because it’s only acting as an additional oil reservoir.

[Adrian II]

The use of the idler gears for returning the oil was a thing on Redditch and EARLY Indian Bullets, it was Bullet Whisperer who mentioned this to me when talking about hie early racing engines which, for the VMCC/BHR series would have to be Redditch. When he first went to crank-mounted CDI racing ignitions he removed the supposedly redundant idler gears only to find that the oil wasn't circulating properly. Stuck 'em back in, all was well.

Fast forward back(?!?) in time (OK, let me think about that one) to circa 1978 and the Chennai/Madras view was "Stuff that, Raj, why don't we just make a weir in the timing chest so that the oil can simply drop back into the oil tank by gravity?", or something along those lines. As you know, Paul, the 350 Electra was a bit special in going to crank-mounted CDI then TCI ignition, but by then the revised system had also long since been applied to "distributor" models too.

Michael Waller, presumably?  Mick Walker (think Ducati) is sadly long gone.

A.

[cyrusb]

I watched Michael Walker’s video where he explained how the distributor idler pinions acted as an oil pump to return oil from the timing case to that return port to the tank. My Electra must rely only on gas pressure and gravity because it has no idler gears, the case is completely empty and redundant above the cams.

It all seems to work very adequately because when I recently took off the cylinder and looked inside the crankcase there was hardly any oil in there, so it certainly isn’t backing up. The oil level in the timing case might possibly sit higher than on some engines, but probably no matter because it’s only acting as an additional oil reservoir.

Exactly. The windage of the geartrain certainly lifts the oil but crank pressure blows it through to the tank. It really is a crude system, but it works.

[Paul W]

Yes, sorry, I meant Michael WALLER. But my iPad obviously thought otherwise and I missed its incorrect correction!

Productive ticks drives my mood….

[Paul W]

Exactly. The windage of the geartrain certainly lifts the oil but crank pressure blows it through to the tank. It really is a crude system, but it works.

My engine only has the oil tank top breather, no breather on the left side mouth of the crank case. If the single breather blocks, I don’t see how oil can return to the oil reservoir because any blow by will pressurise both it and the timing cover. This would explain why my engine smokes as soon as the breather needs cleaning; I can imagine that oil soon backs up into the rocker covers.