Tighter, tightest, twang.... Cylinder head bolts and ignoring your own advice

Bikermike1411

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So, by about 11pm last night I'd done the valves and rocker float on the Gs. RHS was fine, LHS needed a little tweaking, but both are now nice and close to minimum tolerance, lovely. Feeling good I put it all back together and started her up. Fired up instantly, tickover was sweet....then the oil drop from the LH cover started.

Instant level headed wisdom told me "Leave it alone. The engines warm. You'll f@&£ it up. Do it in the morning."

Tired/excited head said 'tweak the bolts, it'll be fine'

Tweak.
Tweak.
Tweak.
Twang. Shit.

Cue one snapped bolt (which is arguably better than a stripped thread) and another hour surgically removing it (level head said the warm block should actually help, which, after drilling the centre and knocking in torx bit, it did.)

Went to bed pissed off that I'd ignored myself, but mildly happy that I'd managed to save the block and hassle of getting an engineer involved.

So....anyone have a spare cylinder head bolt? Ideally some where near Accrington/Bury/Bolton....




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I hate that , happens to me day before trip , nightmare , what bike is it , I'm not near but could post if you happy to wait , hove to check I did have 4 for 1100-1150 oil head

Val

2 bikes , twice is happy 🤔
 
Hi val,
You might be able to save me here! If you do find those bolts please let me know!



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Yeah no worries, I be home 8 this evening and have look , if all well then get your address and send them tomorrow afternoon. That rocker cover bolts yes ?

Val

2 bikes , twice is happy 🤔
 
Yes, the long rocker cover bolts. Let me know if I owe you anything! :)


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You might want to think why it was leaking, not because it wasn't tight enough obviously!
Get a new rubber gasket as well:beerjug:
 
Tim I have NEVER had to replace an 1150 rocker gasket its usually the spark plug tunnel seal

He's very lucky he didn't just jack the threads out of the head! I've had one or two of those to repair usually after owner checked tappets etc and then it leaked and they thought they would just "nip" the bolts up

BIKERMIKE this might help LINKY

You might want to think why it was leaking, not because it wasn't tight enough obviously!
Get a new rubber gasket as well:beerjug:
 
Tim I have NEVER had to replace an 1150 rocker gasket its usually the spark plug tunnel seal

Yes I agree, I've never replaced one either.
The OP's info was vague, so he can just locate the tunnel seal properly, I always rotate mine each time it's off :thumb
 
I know, I know! It was completely my fault and I was even telling myself to walk away before I picked the ratchet up! I'm a genuine tosser.... ;)

I did rotate the plug tunnel seal, but I'm going to check how well it seats when I get home. The RH cover seal was knackered - rotten with the metal inner rusty and showing through the rubber. I was given a genuine BMW one when I bought the bike, so I replaced the RH one with it. The LH one looked fine, but obviously something was amiss. Looking at it now, the bottom half of it (the non-locating edge) has silicone/instant gasket residue on it. Clearly it's leaked before, so I'm going to order a replacement LH seal tomorrow. And fully clean both surfaces while I wait for it to arrive!


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Tim I have NEVER had to replace an 1150 rocker gasket its usually the spark plug tunnel seal

He's very lucky he didn't just jack the threads out of the head! I've had one or two of those to repair usually after owner checked tappets etc and then it leaked and they thought they would just "nip" the bolts up

Believe me, I know.....


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I've just looked at the mating face of the spark plug tunnel on the rocker cover, where the inner seal sits. It has green residue on it - I'm assuming this is another remedial sealing method used to stop the inner seal leaking too.

Given the previous use of instant seal, should I be worried? I'm ordering the inner and outer seals tomorrow just to be certain, but could there be anything else causing an issue?


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Rusty + gasket seal Yeugh

Ask the folks where I linked you all the parts for a pair of used 1150 rocker gaskets and then you will be sure of what you have :thumby

I've just looked at the mating face of the spark plug tunnel on the rocker cover, where the inner seal sits. It has green residue on it - I'm assuming this is another remedial sealing method used to stop the inner seal leaking too.

Given the previous use of instant seal, should I be worried? I'm ordering the inner and outer seals tomorrow just to be certain, but could there be anything else causing an issue?


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Tighter, tightest, twang.... Cylinder head bolts and ignoring your own advice
So, by about 11pm last night I'd done the valves and rocker float on the Gs. RHS was fine, LHS needed a little tweaking, but both are now nice and close to minimum tolerance, lovely. Feeling good I put it all back together and started her up. Fired up instantly, tickover was sweet..

By 11pm last night i was tucked up in bed , coupla beers, dreaming of open roads................... where as you !
 
The rocker bolts are shouldered - they tighten to 9nms (IIRC), which is very little torque. Most people strip a thread before breaking a bolt - so you did well. I got mine all helicoiled on my old 1150 when i was having some other work done on the bike (done in situ). Dealers had already stripped three out of eight threads and I stripped a fourth... :D
 
Tighter, tightest, twang.... Cylinder head bolts and ignoring your own advice
So, by about 11pm last night I'd done the valves and rocker float on the Gs. RHS was fine, LHS needed a little tweaking, but both are now nice and close to minimum tolerance, lovely. Feeling good I put it all back together and started her up. Fired up instantly, tickover was sweet..

By 11pm last night i was tucked up in bed , coupla beers, dreaming of open roads................... where as you !

Sod. ;)


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The rocker bolts are shouldered - they tighten to 9nms (IIRC), which is very little torque. Most people strip a thread before breaking a bolt - so you did well. I got mine all helicoiled on my old 1150 when i was having some other work done on the bike (done in situ). Dealers had already stripped three out of eight threads and I stripped a fourth... :D

Very lucky mate - although I think the bolt must have bottomed out rather than sat on the flange. Being a long thin bolt it didn't take much to break it.

I've been doing this sort of stuff for years (maintenance, not destruction) and this surprised me. But there again, I knew there was a chance it'd go pear shaped. I should just have been more patient and done it today, then maybe I could have gone out today.....

Anyway, gaskets and o-rings ordered, along with two new plugs. I'll see how I get on later this week!


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I know, I know! It was completely my fault and I was even telling myself to walk away before I picked the ratchet up! I'm a genuine tosser.... ;)

I did rotate the plug tunnel seal, but I'm going to check how well it seats when I get home. The RH cover seal was knackered - rotten with the metal inner rusty and showing through the rubber. I was given a genuine BMW one when I bought the bike, so I replaced the RH one with it. The LH one looked fine, but obviously something was amiss. Looking at it now, the bottom half of it (the non-locating edge) has silicone/instant gasket residue on it. Clearly it's leaked before, so I'm going to order a replacement LH seal tomorrow. And fully clean both surfaces while I wait for it to arrive!


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make sure all the surfaces are DRY.

especially the rubber gaskets.

;)
 
Bollox to that!!!

Get red rubber grease (Brake grease) and coat every thing! Including the Spark plug caps

You could splash out and get an old friends sworn remedy for all rubber maladies "Gummifledge"

I have been coating peoples gaskets and Spark leads in Rubber grease for over 10 years of servicing and have NEVER had to change one

make sure all the surfaces are DRY.

especially the rubber gaskets.

;)
 


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