71 knock/click Burned valve pics

I got the details from Dean today on the engine rebuild. Looks like he did a full rebuild a long time ago on this motor. He knew the previous owner too and I guess he didn't do too much riding at all. The barrels show this as the cross hatch is still very visible. He confirmed the pistons as combat type. Also confirmed the rebuild as a mild stock rebuild with a stock cam etc.

I'm gonna put it back in his hands to see what has happened. I am hopeful its not too much of a fix. I have no problem doing the heavy lifting so to speak.

If that there SLOT going to the OIL RING



Goes Right Across Behind the Oil Ring , joining with opposite Slot ; theyre the ' top falls of over 6.000 Jobs .

Real pistons , the Land behind / under the OIL RING just has HOLES drilled through , about 3 mm dia, so metals continuous behind .
Should be able to see glareing up inside , or just pull out and slip oil ring onto the skirt below .
If the ring rotates ( not stuck ( obviously ) ) , prying it clear with fingernails , you just slip it ( them ? 3 piece ) out enough to drop .
The 3 piece are near unbreakable .

If youre splitting the cases , GO for a notorious Combat ' S S ' camshaft .

So I finally dropped the head off at Dean Collinsons shop this morning. I came back this afternoon to have a chat with him and he took a look a tit right there and gave an assessment...

He pulled the affected valve and noticed that the valve had a piece of the valve guide stuck to it. This came from the severe heat. He also pointed out a substantial amount of carbon build up on the valve stem right where it leads into the guide. He told me that it looks like that there would be a possibility that a piece of carbon broke off and got into the valve stem and this could have caused the valve to not fully close.

I woulda took pics there in his shop but I didnt want to look like a dillweed... I mean more of a dillweed than I already look. I kinda regret it though, his shops cool, he had some nice bikes in there including a real nice Kenny Dreer 880...

I may get the head back next week and then ill continue this saga!!!

Ugh, better ask him to discuss sources of extra carbon to coke up with.

hobot said:

Ugh, better ask him to discuss sources of extra carbon to coke up with.

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Yeah I suppose a question or two would be how the carbon got there!

I was too busy asking him over and over how its not carburation etc. I was convincing myself the carb leaning out was the issue. But he asked me if both carbs are close to each other in adjustment and they are identical... So that being said i will patch it back together when hes done with the head and we will se ewhere that takes me.

These things are just as fun working on as riding. I am also glad I finally ran into Dean as he lives really close. He comes recommended by Bill Bibbiani too. Glad I have someone I can contact when I am in a clutch situation face to face. I can get pretty far with the help of the boards etc but hainvg a shop close by is awesome.

i sat on the side of the interstate for an hour or so about 2 months back with the norton. a single harley rider was the only person to stop out of the hundred or so bikes that went by...

i think i need a friendlier state...

These things are just as fun working on as riding. I am also glad I finally ran into Dean as he lives really close.

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Ugh southerntea not for me trying to solve mystery I'm not trained or equipped for. Having a competent helper-rescuer makes all the difference. Your plot has both thickened up and narrowed down with from Dan's little question and comment. My mechanical fun comes from customizing new stuff and modifying perfectly good old stuff. Once ya get out and about it will seem like half the world once had a Norton but for some reason it was too much for them to keep.

Take a CAMERA , im sure he would be glad to have us all look in side his workshop . :roll: :wink: Might pay to ASK first . 8)

[

Yep, You just had a siezed valve/guide
Possibly not Re-sized after fitting, you know the story..Knock in a new one and ends up a bit tight. But inlet sucking oil and cool air..nornally get away with it.

quote="iceteanolemon"]So I finally dropped the head off at Dean Collinsons shop this morning. I came back this afternoon to have a chat with him and he took a look a tit right there and gave an assessment...

He pulled the affected valve and noticed that the valve had a piece of the valve guide stuck to it. This came from the severe heat. He also pointed out a substantial amount of carbon build up on the valve stem right where it leads into the guide. He told me that it looks like that there would be a possibility that a piece of carbon broke off and got into the valve stem and this could have caused the valve to not fully close.

I woulda took pics there in his shop but I didnt want to look like a dillweed... I mean more of a dillweed than I already look. I kinda regret it though, his shops cool, he had some nice bikes in there including a real nice Kenny Dreer 880...

I may get the head back next week and then ill continue this saga!!![/quote]

Well when I go back I can ask him if he would allow me to snap a pic. I know it could be a yes or a no since the Norton community is rather small and there could be a chance he wants to keep the contents of his shop anonymous or possibly he could have security issues since its his house. My dad told me to ask him about bonneville pushrod tube leaks and hide a recorder in my pocket. heheh it seems the longer the bikes are around the more valuable the handed down tech is. I can only imagine what it will be like in 30 years. It will be much harder to get a professional involved. I guess I better get my own valve tooling.


Going to drop off the cyl barrel for paint removal and light hone today. I have the followers out and numbered.

Got rings and seals on the way too. Bought new exhaust crush seals too.

Nowadays Im more worried about banging up the nice stuff when putting the bike together than anything else.

Hm, hi heat on guild could cause carbon to collect, which brings us back to why the extra heat there. I'm hoping it was just some ring/bore blow by oiling now solved unknown by renewing this to seat well soon.

Well I just got back from the metal shop. Adams Mettalizing, they do lots of car and harley stuff. Good guys and they know their cyl bores.

The guy there looked at my cyl barrels and noticed that the hone would not clear up a issue in the left side. There must have been a small bit of moisture that got in there a long time ago as it looks like a stain. The guy told me that needed to be bored to be gotton rid of and it likely was a issue. (not related to the valve burnup) I did see the stain and thought it wouldnt be a big deal and just to have the pros make an assessment on it and go with that.

So looks like I am going to be looking for pistons now. The plot always thickens.

im 20 over now so I guess its safe to say I am going to go to 40 over...

Plot thinning out if bore fault and guide issue both on same side. Maybe enough oil got in to both mildly detonate heat up to point of coke up to point of jam up?

Whoever does the cylinder boring should tell you what size over pistons to buy not the other way around. It is unknown how deep this "stain" goes.

Russ

batrider said:

Whoever does the cylinder boring should tell you what size over pistons to buy not the other way around. It is unknown how deep this "stain" goes.

Russ

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Well they suggested I go to .040 when I was there this morning. They didnt bore it before suggesting but the guy had a close look and made that assessment. I will be hopeful its cleared out when I get it back. If its not I guess it was a bad diagnosis!

Not sure that a re-bore will prevent valve's from burning...but i am not to old to be taught.
A stain in the cylinder and just a stain,just requires a glaze bust and new ring's :?: When you said didnt think it would clean up...did they try?
Staining and cylinder water attack from standing would have shown up as smoke on your first outing? Gradual failing like you had is just a valve sticking problem.
Tipical over reaction, a friend a few years back was convinced his harley FXS had a bigend knock, striped the motor..nothing wrong...but just in case the micro play in one rod was the cause he had the engine rebuilt...turned out in the end to be a hydraulic tappet stuck!!

If the marks are visable ( hone ) over the stain, its unlikely its soft there . ALSO pistons & finished size are matched for clearance .

If it is the horrible slotted ones in it , theyre SAFE to 6000 . Might pay to save the loot for future use , perhaps .

john robert bould said:

Not sure that a re-bore will prevent valve's from burning...but i am not to old to be taught.
A stain in the cylinder and just a stain,just requires a glaze bust and new ring's :?: When you said didnt think it would clean up...did they try?
Staining and cylinder water attack from standing would have shown up as smoke on your first outing? Gradual failing like you had is just a valve sticking problem.
Tipical over reaction, a friend a few years back was convinced his harley FXS had a bigend knock, striped the motor..nothing wrong...but just in case the micro play in one rod was the cause he had the engine rebuilt...turned out in the end to be a hydraulic tappet stuck!!

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Yeah no doubt the issue with the cyl and the valve burning are absolutely not related.... I just discovered the stain and wanted to do "due diligence" and clean it up.... I like to make all things right while its out. The metalizing guy did not attempt to clean it up with a hone but instead took a look at it and gave me his opinion based on the stuff he has seen come through the shop. They are pretty old school and been doing it a while, I was convinced he has seen it before since he noticed it right away.

I am hopeful he gets it right when they get the pistons and everything in one place. Of course murphy can always strike!

The bike really didnt do much than a small puff on cold startup and it had awesome compression (before the valve issue).

The last time the motor was rebuilt head off and valves out was in 1993! So I guess it was bound to happen? I got the history on the bike and the P.O. let it sit for a LONG time. When I gfot it it also had a few things messed with wrong, front fender was backwards, some repaint on the cyl barrels, headlamp was mounted without the spacers, wrong exhaust brackets, cable ran wrong etc. So I knew there was a few things but nothing huge. Just looked like the P.O. was a tinkerer but not a stickler for the details Stuff that irritates me but I am sure I will find more going forward. So far these things are just annoyances unlike bad machine work or screwed up permenant stuff which would make me puke.

Ok, Your decission for a re-bore was down to the "lads" Its just a few dollars more,and one bore life less, Doubt you will be wearing the cylider out in your life...could be wrong .
I used to add a spot of castrol R to my fuel, Thinking the cylinder got a light oil on stop starting..and the slight wiff of "R" was FAB!

Never had any probs, but i never had a bike that i did megga miles on...no doubt some lads here will express their views....but remember since lead was replaced with ...what ever? A bit of upper lube in my book is a must today with modern pump p*ss. or Lead replacement :?:

Did lead in OLD fuel coat the inlet valve stem, food for thought?

john robert bould said:

Ok, Your decission for a re-bore was down to the "lads" Its just a few dollars more,and one bore life less, Doubt you will be wearing the cylider out in your life...could be wrong .
I used to add a spot of castrol R to my fuel, Thinking the cylinder got a light oil on stop starting..and the slight wiff of "R" was FAB!

Never had any probs, but i never had a bike that i did megga miles on...no doubt some lads here will express their views....but remember since lead was replaced with ...what ever? A bit of upper lube in my book is a must today with modern pump p*ss. or Lead replacement :?:

Did lead in OLD fuel coat the inlet valve stem, food for thought?

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Ill ride it till I have to rebore, mthen ride it till I have to re sleeve I guess.... Took 2 hours to get the head and cyl off and as long as I dont have to do it 3 times a year I will be happy! If it was a track bike ugh I guess it would be tinkertown for me!!!