Author Topic: GB is not OK, again!  (Read 3993 times)

Online Greybeard

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Re: GB is not OK, again!
« Reply #90 on: 14.06. 2018 22:59 »
The engine started, sounding just the way it should.

Online metalflake11

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Re: GB is not OK, again!
« Reply #91 on: 14.06. 2018 23:16 »
You did replace the 'spacer washer' with a cork I presume GB?
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Offline stanwhite

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Re: GB is not OK, again!
« Reply #92 on: 15.06. 2018 00:28 »
When I was young, foolish, and damn'd quick, me and my 850 Norton went to Holland, and I decided to run it around the Zandvoort circuit

I really gave it the beans... And then a horrible noise. Just like Greybeard's...  I came into the pits gently, and the noise went away. Subsequent investigation back home revealed that when I had got it good and hot, a valve guide had come loose!!

The trouble is, that will be hard to find, When the head is hot, and the guide loose, it makes a hell of a racket, because it is moving within the head,

 This could put a lot of strain on the followers, as they are now trying to ram the guide back in place?

I noticed someone said that the pipe was a little "blued" on one side. My GF pipes are only "light straw" at most. Check ignition timing, carb mixture, and if there is a problem leading to overheating, fix that first, and ride very gently. See if all is OK then.

 If it is, I am guessing you will then have to have the head off, and check the guides. Check for evidence of one valve stem being cleaner along its length in a different position to other valves.

All the foregoing could be "brown smelly stuff"  as a result of that being 45 years ago!!!!

Head experts, anyone?

My Norton? They gave me a new head, under warranty. Hope your head is not drastic.

 Cheers,

 Stan.

Online metalflake11

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Re: GB is not OK, again!
« Reply #93 on: 15.06. 2018 00:55 »
When I was young, foolish, and damn'd quick, me and my 850 Norton went to Holland, and I decided to run it around the Zandvoort circuit

I really gave it the beans... And then a horrible noise. Just like Greybeard's...  I came into the pits gently, and the noise went away. Subsequent investigation back home revealed that when I had got it good and hot, a valve guide had come loose!!

The trouble is, that will be hard to find, When the head is hot, and the guide loose, it makes a hell of a racket, because it is moving within the head,

 This could put a lot of strain on the followers, as they are now trying to ram the guide back in place?

I noticed someone said that the pipe was a little "blued" on one side. My GF pipes are only "light straw" at most. Check ignition timing, carb mixture, and if there is a problem leading to overheating, fix that first, and ride very gently. See is all is OK then.

 If it is, I am guessing you will then have to have the head off, and check the guides. Check for evidence of one valve stem being cleaner along its length in a different position to other valves.

All the foregoing could be "brown smelly stuff"  as a result of that being 45 years ago!!!!

Head experts, anyone?

My Norton? They gave me a new head, under warranty. Hope your head is not drastic.

 Cheers,

 Stan.

Not a bad shout that Stan, more common in ally heads, but certainly a fair possibility!

I recommend 20 minutes per pound, and twenty for the head at regulo five, then check for a loose guide.
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Offline stanwhite

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Re: GB is not OK, again!
« Reply #94 on: 15.06. 2018 01:04 »
At which point do you baste it? *smile*

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Re: GB is not OK, again!
« Reply #95 on: 15.06. 2018 08:09 »
G'day GB.
If it sounds good cold and makes the noise hot I'd have money (or a kiss) on a loose guide as mentioned by Stan.

The cam pinion buts to a shoulder on the camshaft, the cork between the pinion and breather should have crush to push the pinion against the outer bush, no more end float. If the cork is omitted the shaft can flop around like a cock in a sock, then a lobe can work on two followers and all hell breaks loose.
Cheers
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Online Greybeard

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Re: GB is not OK, again!
« Reply #96 on: 15.06. 2018 08:42 »
You did replace the 'spacer washer' with a cork I presume GB?
Yes Bob.

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Re: GB is not OK, again!
« Reply #97 on: 15.06. 2018 08:59 »
Guys, the blue on the exhaust is historic. When I returned yesterday I felt the oil tank. It was just warm. The engine did not smell or feel very hot. During the ride I pulled in the clutch to see if the engine was tight; it just kept running beautifully.

I will check valve guides.

This business with one of the tappet adjusters going in much further is crazy. Logically, either one pushrod has been shortened, but they all have their rounded tips and all were straight, or one of the new SRM followers was shorter than the others, but I'm sure they are identical, or there is something very wrong with the camshaft, or that rocker arm is bent, but it doesn't appear to be.

Needless to say, I'll be taking the top off and inspecting things very carefully, AGAIN!!!

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Re: GB is not OK, again!
« Reply #98 on: 15.06. 2018 09:09 »
G'day GB.
If it sounds good cold and makes the noise hot I'd have money (or a kiss) on a loose guide as mentioned by Stan.

The cam pinion buts to a shoulder on the camshaft, the cork between the pinion and breather should have crush to push the pinion against the outer bush, no more end float. If the cork is omitted the shaft can flop around like a cock in a sock, then a lobe can work on two followers and all hell breaks loose.
Cheers

While I was reassembling the cases with the new camshaft I noticed there was about a 1/16", 2mm of endfloat. I found a thin washer to put behind the pinion but removed it when I read that the breather cork controls endfloat.

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Re: GB is not OK, again!
« Reply #99 on: 15.06. 2018 09:35 »
G'day GB.
If it sounds good cold and makes the noise hot I'd have money (or a kiss) on a loose guide as mentioned by Stan.
I'll start the engine today. If it's quiet I reckon you may have it.

Online RoyC

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Re: GB is not OK, again!
« Reply #100 on: 15.06. 2018 10:12 »
If it is the guide or even from the wrong coletts hammering the one tappet, it could have very slightly straightened that one rocker, especially with the loud bang that you heard.
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Online Greybeard

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Re: GB is not OK, again!
« Reply #101 on: 15.06. 2018 10:40 »
I've just gone and started the bike. The rattle is still very evident :( Doesn't mean a valve guide is not loose. I'll be checking them.

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Re: GB is not OK, again!
« Reply #102 on: 15.06. 2018 11:27 »
Happy 1K likes. The most liked man on the forum. *yeah*
Feel better now?
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Online Greybeard

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Re: GB is not OK, again!
« Reply #103 on: 15.06. 2018 13:09 »
Happy 1K likes. The most liked man on the forum. *yeah*
Feel better now?
Cheers

Really? All those bribes have paid off!

Online Greybeard

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Re: GB is not OK, again!
« Reply #104 on: 15.06. 2018 13:20 »
I took the tank and rocker covers off this morning to discover that the drive side Inlet tappet had about 1/4" gap! I must have got the pushrod on the edge of the cam follower when I last adjusted it  *red*.

I found that to get both of the Inlet tappet gaps correct I had to thin the locknuts on my bench grinder! Why both of the Inlet tappets are so far screwed down I do not know.

I did consider fitting the locknuts below the rocker arm but my fingers are not as clever as they used to be and I felt sure I'd drop the buggers down the pushrod tunnel!

I've put the bike back together and started it. It sounds GREAT! After lunch, I'll be out for another ride.

I'D LIKE YOU ALL TO CROSS ANY PARTS OF YOUR BODY THAT YOU FEEL ABLE TO CROSS. ITHANKYOU!