[Beavs1906]

Hello, I have an Electra AVL 2007 XS so it has a Rev counter. Just below 2000 rpm it has a light random tapping sound coming in about 1800 and gone at 2000 rpm. It’s totally engine speed related. Throttle position doesn’t change the sound or random nature. It sounds like loose tappet but I know they are borderline tight. The primary chain has been re adjusted and is not loose.
I am thinking about checking the cam wheels for excessive end float as there are shims available. So some advice please how would you measure this. Would it be removing the cam followers and lever both cams back and forth through the inspection window with the cover back on  to assess movement. Thanks in advance 🙂

[AzCal Retred]

I had an IB ES350 Bullet with scoring on the idler gear shims from the newer style too-thin timing cover gaskets. I used this material to determine each gear's end clearance:
Sealed Power SPY1 Plastigage ; $5.57 ;  ( Range: 0.009" - 0.020" )
https://www.amazon.com/Sealed-Power-SPY1-Plastigage/dp/B001P277WG/ref=sr_1_17?dchild=1&keywords=plastigage+PL-C&qid=1627537202&s=automotive&sr=1-17

This is found in the Iron Barrel section in the "What's the best way to set shim spacing for gears under the Timing Cover?" entry. There are pictures in there of the "plastgage" methodology used. Hitchcock's has a variety of idler & cam shims available. Get a selection of the standard as well as the "accessory" shims to cover contingencies. I never found an "official" endplay spec, so I shot for 0.007" to 0.015". The SPY1 plastic gage falls right in there. There seems to have been a change in the available timing cover gasket thickness, the new ones being thinner, so my ES350 ended up too tight and did some galling to the endplay washers. On those I ended up honing the damaged units thinner and back to flat by hand on a handy carborundum whetstone, ending up with about 0.008" on one idler and 0.015 on the other.

Pulling off the timing cover is a good idea, lots of things to keep tabs on in there. Check the tappet side play at TDC compression with the valves well slacked off. My 500 has perceptible side play in the tappets just above the cam and is VERY noisy, you could flick them from side to side and see just where the extra "clank" comes from as they slip over center on the cam nose. My ES350 is quiet, for a Bullet, and does not exhibit this side play. The tappets & guides are definitely due for replacement on the 500. Again, Hitchcock's carries all the tools and bits. Take a look at the oil pump worm shaft gear at the same time. My ES worm had some wear and had the high volume pumps installed, so I went back to stock volume pumps.

Good hunting - ACR -

[Beavs1906]

Thanks for your reply, plastgage is a good call, I haven’t used that for 40 years, I used it to check crankshaft and shell clearance during engine rebuilds. Think during winter I will have to investigate the noise, I just like engines to sound sweet. It doesn’t seem to get any worse but I’m sure it could be quieter.

[Beavs1906]

Will check cam followers  at tdc too , that would fit with the characteristics of what I’m hearing. Thanks

[allanfox]

Your Cam backlash is adjustable on the AVL engine, could be that?

https://www.youtube.com/watch?v=TIL-fTzpqHU

Have done mine and not hard to do, lots of info about on this (in manual) and just attached the one above as an exemplar

[Beavs1906]

Thank you Allan. Eccentric cam spindles 👍 the link is a great help. I will have a look during the next week and report back what I find.

[Beavs1906]

There was no detectable backlash between any of the cam lobe gears with the engine cold. I suspect there would be a little more with hot thinner oil and the crankcase hot. I’m sure it’s ok and a valid check out of the way.

 I also used a small dot of blu tack to try to gauge the cams end float and estimate it to be between 0.003 to 0.006 looking at the amount it had compressed with temporary fitting of the cover so again I would say it’s ok.