What Did You Do With Your Commando Today?

Schwany said:

Not much worry about a Norton tappet being off center. One would have to go out of their way making shims to get them in the center of the valve stem.

Once a soft tappet starts to deteriorate there's no way it won't ware on the valve stem. If one has never had a soft tappet aka adjuster screw start to deteriorate, one would never have seen it.

The valves that have the stellite lash caps on the stem don't show any ware at all obviously, and the stellite is tuff stuff. The lash cap might show a shinny area where the tappet was tapping after 10K miles, but no divot.

Forgot to mention I have no idea if my valves are spinning correctly or not to make the seats last. My seats are the original ones lapped a little every time I take the head off, and I can't see in there while the motor is running anyway.

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My bike has Kibblewhite Black Diamond valves I believe which use their own coating, no idea how this compares to Stellite but well I suppose considering the state of the adjusters. I guess I should be thankful one actually broke otherwise I’d be none the wiser then who knows what damage could have resulted?

Valve stem survived, phew.

I've just run into the same situation with the same style adjusters but only on the exhaust side. I'm going back to the old style adjuster. If the elephants foot style failed after not that great a mileage on a motor that has had a rather gentle life then I think I'll forego the risk of bits of shrapnel.

zotz said:

I've just run into the same situation with the same style adjusters but only on the exhaust side. I'm going back to the old style adjuster. If the elephants foot style failed after not that great a mileage on a motor that has had a rather gentle life then I think I'll forego the risk of bits of shrapnel.

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According to Matt there was a faulty batch of these many years back (my bike was built in 2013, 12.5k miles back). Matt has long since used these with zero issues
Easy fit

Went for a shortish run today as the weather was too good to miss. As usual, plenty of onlookers!
I guess the drake wasn’t so impressed

I’m still hearing that bloody noise @ 3.75k from time to time when accelerating quite hard I’m thinking it’s most likely the slides in my FCRs, is that likely?

Café au Lait said:

I’m still hearing that bloody noise @ 3.75k from time to time when accelerating quite hard I’m thinking it’s most likely the slides in my FCRs, is that likely?

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Only time I definitely hear something inside the 35mm FCRs is at idle. I think it's a pulse of air pushing back or pulling forward on the slides. They have done it since brand new. I'm not concerned about the slides being damaged. I wonder if they wouldn't do it with the balance tube removed and the tube ports plugged. I have not tried that to find out. Some people claim thy have never heard the slides doing anything. Mine are really quiet when the engine is not running.

Long shot guess: If the accelerator pump is disabled it could be lean detonation or what I would call pinging.

Café au Lait said:

Went for a shortish run today as the weather was too good to miss. As usual, plenty of onlookers!View attachment 118836
I guess the drake wasn’t so impressed

I’m still hearing that bloody noise @ 3.75k from time to time when accelerating quite hard I’m thinking it’s most likely the slides in my FCRs, is that likely?

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Have you checked that the vacuum release plate seals are still in good shape?
If not the plates could rattle on the front of the slides - likely to cause a noise.

I’ve not looked no as I’m still uncertain where the noise is emanating from. It kinda sounds like the carbs (that metallic hollowness of the FCRs) but then it’s very audible over the rest of the sounds when opening the taps which I question whether the slides would be that loud. It only occurs at that rpm (3.5-4k) only on hard acceleration never deceleration or idle or even revving at a standstill. Gentle acceleration to that point also never occurs, weird eh? I tried to record it but the wind blast was louder.

I guess I need to get someone familiar with these and the bike in general to take it for a spin and offer an opinion.

Café au Lait said:

I guess I need to get someone familiar with these and the bike in general to take it for a spin and offer an opinion.

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From the horror stories I've read about vacuum plates fracturing, getting sucked in and holding valves open, I'd look sooner rather than later

Café au Lait said:

I guess I need to get someone familiar with these and the bike in general to take it for a spin and offer an opinion.

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It's not difficult to remove the slides - I know you've had the tops off. The vacuum release plate just spigots onto the forward projection on the roller-slide with the seal between them.
The only drama is re-synchronising the two slides - not a biggie.
Cheers

Café au Lait said:

My bike has Kibblewhite Black Diamond valves I believe which use their own coating, no idea how this compares to Stellite but well I suppose considering the state of the adjusters. I guess I should be thankful one actually broke otherwise I’d be none the wiser then who knows what damage could have resulted?
View attachment 118828View attachment 118829
Valve stem survived, phew.

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I had a conversation back in 2016 with Jim Comstock about these Mushroom Adjusters and I believe there was a bad batch made so this isn't the first time I have seen this. I took mine off when I rebuilt my RH10, 850 head and these were fine with about 80,000 miles on them. No pitting whatsoever. I had a Mega Cycle Cam N-R-560 if my memory serves me right. 0.013" tappet clearance with flat lifters. Not sure if cam shafts made the difference. They are glass hard though. I found that out when I put a slotted screwdriver on the slot of one of the adjusters and a small chunk broke off which I had to fish out for with a magnet. Here is a link to that conversation:

concours said:

View attachment 118860View attachment 118861

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Better watch out or the original paint gang will be after you…

Out of hibernation - oil filter change, clutch plates cleaned, battery charged and re installed, chains adjusted , haze polished off bright work , paint waxed , nut and bolt check . Weather permitting, tomorrow will do tire pressure and add oil and first ride of the season. I would do it today but this afternoon is that glorious time that all old men look forward to - prostate exam.

Café au Lait said:

I’ve not looked no as I’m still uncertain where the noise is emanating from. It kinda sounds like the carbs (that metallic hollowness of the FCRs) but then it’s very audible over the rest of the sounds when opening the taps which I question whether the slides would be that loud. It only occurs at that rpm (3.5-4k) only on hard acceleration never deceleration or idle or even revving at a standstill. Gentle acceleration to that point also never occurs, weird eh? I tried to record it but the wind blast was louder.

I guess I need to get someone familiar with these and the bike in general to take it for a spin and offer an opinion.

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I'm guessing you have talked (emailed) to Matt about the sound you are hearing. I would not tear the FCRs apart before talking to him.

If it is pinging which it could be if it only happens on quick WOT events. It could be an accelerator pump timing issue. Fiddly trial and error process but not hard to correct. Might also be you just need to lift the needle a notch (move the clips down or drop in a half step shim under the current clip position). If you are not a tuner, you might want to consider finding somebody that is.

Schwany said:

I'm guessing you have talked (emailed) to Matt about the sound you are hearing. I would not tear the FCRs apart before talking to him.

If it is pinging which it could be if it only happens on quick WOT events. It could be an accelerator pump timing issue. Fiddly trial and error process but not hard to correct. Might also be you just need to lift the needle a notch (move the clips down or drop in a half step shim under the current clip position). If you are not a tuner, you might want to consider finding somebody that is.

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Did 96 miles today, bike went like a dream but numerous noise events although none in the last 20. Cruising at 80 and then WOT to 90 (5k) and everything was buttery smooth both aurally and mechanically.

I certainly won’t be pulling anything apart until I know I’m on the right track. I’ve previously had the carbs out and changed the needles, I’m comfortable with that; that solved a mixture issue which hasn’t returned.

To be honest I really think I’m barking up the wrong tree, just too audible to be from the carbs themselves. I’m now of the opinion it’s from the right hand exhaust output but with my custom earplugs trying to work out from where the noise emanates is tricky. I may well do a short run without plugs once the bike is fully warm, WOT is pretty deafening without them though.

I’m out for another shorter trip tomorrow I may well replace the plugs first as I know they can cause many an issue and then contact Matt.

FTR the sound is better described as a ‘bark’ or like that of a goose’s ‘honk’ and lasts less than a second.

Café au Lait said:

Did 96 miles today, bike went like a dream but numerous noise events although none in the last 20. Cruising at 80 and then WOT to 90 (5k) and everything was buttery smooth both aurally and mechanically.

I certainly won’t be pulling anything apart until I know I’m on the right track. I’ve previously had the carbs out and changed the needles, I’m comfortable with that; that solved a mixture issue which hasn’t returned.

To be honest I really think I’m barking up the wrong tree, just too audible to be from the carbs themselves. I’m now of the opinion it’s from the right hand exhaust output but with my custom earplugs trying to work out from where the noise emanates is tricky. I may well do a short run without plugs once the bike is fully warm, WOT is pretty deafening without them though.

I’m out for another shorter trip tomorrow I may well replace the plugs first as I know they can cause many an issue and then contact Matt.

FTR the sound is better described as a ‘bark’ or like that of a goose’s ‘honk’ and lasts less than a second.

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It's not something silly like the front brake pads rattling is it
I had this happen with a a pair of six pots on a special I was working on
It sounded like the noise was coming from under the tank at certain revs

baz said:

It's not something silly like the front brake pads rattling is it
I had this happen with a a pair of six pots on a special I was working on
It sounded like the noise was coming from under the tank at certain revs

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I doubt it as it can occur in any gear not just one wheel rotation speed but I’ll take a gander, thx

As this last winter approached, I noticed that I had a growling sound at idle. A growl or a grinding sound is not a good sound for an engine. It's usually the sound of metal on metal, and since it was happening at idle I thought it was most likely the followers and the cam given that their oil film is weaker at low rpm's.

At first I tried an endoscope camera to look inside the crankcase, which doesn't actually give a good enough camera picture to do a diagnosis. Eventually I bit the bullet and I pulled the head and barrels to investigate my growl and found 2 followers that had some surface pitting starting to form on them. One was very minor and I thought the other might be rough enough to be the source of my growl so I resurfaced all of them

The cam lobes weren't perfect, but looked ok, so I took a chance with them since I've seen a lot worse. Upon reassembly and a few subsequent test rides, the growl is gone (for now) so I think my diagnosis was right... If it comes back quickly this coming riding season, I'll open it up again and change the camshaft and probably get a new oil pump... but I don't ignore odd noises coming from the crankcase.

Odd engine noises have a cause. If it's coming from inside the crankcase my advise is to have a look... I would take the primary cover off and run the bike. It would be a lot less of a pain in the ass if your noise turned out to be a primary case noise rather than a crankcase noise.

Before I pulled the head and barrels, I'd also take the timing side cover off just to make sure you don't have a problem in there because that could also be a much easier fix than a crankcase issue.... Ultimately, it sucks to have these kind of issues, but if it turns out to be a crankcase noise, you'll probably have to take a look inside at some point.

Café au Lait said:

Did 96 miles today, bike went like a dream but numerous noise events although none in the last 20. Cruising at 80 and then WOT to 90 (5k) and everything was buttery smooth both aurally and mechanically.

I certainly won’t be pulling anything apart until I know I’m on the right track. I’ve previously had the carbs out and changed the needles, I’m comfortable with that; that solved a mixture issue which hasn’t returned.

To be honest I really think I’m barking up the wrong tree, just too audible to be from the carbs themselves. I’m now of the opinion it’s from the right hand exhaust output but with my custom earplugs trying to work out from where the noise emanates is tricky. I may well do a short run without plugs once the bike is fully warm, WOT is pretty deafening without them though.

I’m out for another shorter trip tomorrow I may well replace the plugs first as I know they can cause many an issue and then contact Matt.

FTR the sound is better described as a ‘bark’ or like that of a goose’s ‘honk’ and lasts less than a second.

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Honks?

I don't think I've experienced a 3.5-4K honking fit from my Norton. The reed breather will honk getting the pistons just over TDC when the engine is stone cold, but that is the only time my engine lets out a honk.

You'll figure it out.

Richard Tool said:

Better watch out or the original paint gang will be after you…

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LOL, sokay. I had to de-rust the inside, and now blast the outside prior to pressure testing.
I have pics somewhere, before the strippers came