Author Topic: cylinder head  (Read 2937 times)

Offline 0116harley

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Re: cylinder head
« Reply #15 on: 26.12. 2011 20:23 »
Hi everyone back to work on the bike soon. Im gonna make my own rocker cover gaskets as suggested, Is it a good idea to use a gasket sealent as well, as i find no matter how hard i try these always tend to leak a small amount of oil from the covers
cheers neil
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Online RichardL

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Re: cylinder head
« Reply #16 on: 26.12. 2011 22:23 »
Neil,

Some info here about leaks at the rockerbox joint and a clever way to avoid them.


http://www.a7a10.net/forum/index.php/topic,2912.msg19879.html#msg19879

Richard L.
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Re: cylinder head
« Reply #17 on: 08.04. 2020 20:15 »
well you bsa chaps while I have had lots of time to do things I have lightened two inlet rockers this afternoon for the berger build,  weighed at 95.2 and 91.2 g they are now 82 and 80.3g , I don't want to take any more off. musky or any of you racer chaps out there has this been worth doing and is there enough weight  been taken off, any way to the point about rocker arm angle, I took the covers off betsy the beezer to check clearances and then discovered this thread *computer*. I looked at the inlets and one valve was open , the adjuster tappet screws nearly fully out and the angle shocked me *pull hair out* I looked at the exhausts and adjusters about right in the middle and open / closed angle ok. the bike runs fine --- well it will it's a beezer. then the penny dropped, the barrel has been skimmed the two faces of the head and the rocker box, if only I had had a computer years ago I would have been edumacated on this topic. I just wondered why it doesn't really effect the exhausts as such, is it because they are longer arms and the inlets are little stumpy's *dunno* thick me *bash*
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Online muskrat

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Re: cylinder head
« Reply #18 on: 08.04. 2020 21:02 »
G'day berger.
At half lift of the valve the adjuster should be dead in line with the valve stem. If one adjuster is out along way compared to the other it could be the pushrod is sitting on the edge of the cup.
Cheers
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Re: cylinder head
« Reply #19 on: 08.04. 2020 22:50 »
hello musky built it back up in a hurry a couple of years ago ,  they are both in the cups, done lots of miles like this and I just looked again and took a feeler to the rocker arm and I can't get a 2thou between spring keeper and rocker arm even though I can set tappet clearance .rocker is possibly just interfering with keeper, this is the result of losing about 45 thou from top of barrel all the way to the rocker box  [ be warned *problem* ]. or I have picked up a couple of longer push rods not realising when in that rush to get it done *bash*  it has to come OFF!!! *pull hair out* *pull hair out* if I find the push rods are proper it has to be the vast  skimming in which case I will be making a thick copper gasket set for it *work* but why are the exhausts perfect *conf2* I will find out tomorrow, ps is  10 or 12g off rockers about right or is more lightning needed.
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Online berger

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Re: cylinder head
« Reply #20 on: 09.04. 2020 12:22 »
just before I attack this rocker box here is a piccy of inlet valve, I am still on my old phone so piccy isn't too good but you can see how close rocker arm is to valve spring keeper, you can just blow air through the gap I tried my new phone for this but I need to drastically reduce and I haven't mastered that yet, thick me *computer*. following is a picky of the exhaust which is normal, I haven't mastered putting more than one piccy in the same thread sorry, thick me *computer*
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Online berger

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Re: cylinder head
« Reply #21 on: 09.04. 2020 12:24 »
exhaust which appears normal investigation needed me thinks *work*
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Offline RDfella

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Re: cylinder head
« Reply #22 on: 09.04. 2020 12:36 »
Is the valve seat badly recessed? That's let the valve stem come higher and have same effect as a too-long pushrod. Arm is only close to collar because tappet adjustment is almost right out.
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Re: cylinder head
« Reply #23 on: 09.04. 2020 14:49 »
RD fella I thought about valves aswell, i'm trying to scratch my brain cell as to how it was after I built it up from scratch when I had oil pipes on wrong and this latest time when I just did top end in a desperate hurry after it locked up coming away from bulldog bash, I am on it now and who can tell me the difference between rocker spindle thrust washers 67-60 six of and 67-61 two of is it the thickness because I have just measured some spares and there isn't a definite conclusion  cheers
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Online berger

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Re: cylinder head
« Reply #24 on: 09.04. 2020 17:36 »
think I have it, I rebuilt it the last time with four push rods that came with loads of bsa bits saving mine for the berger build. the inlet tappets have taken a bit of a hammering *bash* I will change those, and the valves have survived. so this is what I have found all valves sit in the head with only 5 to 10 thou difference in the height of the top of the stems.  the inlet push rods I fitted are 8 and 1/8th long . the ones I had in for years are 8 and1/16th. the reason the exhausts looked ok is because those push rods were just 9 inch, my old ones are 9 and 1/16th, the bit longer inlet push rods plus about 3/64ths taken from all surfaces of barrel / head etc has combined to create this problem *problem* now I think I will have a cuppa tea and stop scratching my brain cell. I live and learn again ,
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Offline Swarfcut

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Re: cylinder head
« Reply #25 on: 09.04. 2020 19:19 »
Bergs. Yes, no, maybe.....

 In my archives I have          A7        Inlet  Push rod   8 1/16"         Exhaust Push rod     9"

                                          A10       Inlet                8 1/2"           Exhaust                 9  1/2"


 See how this stacks up with official published data and what you actually have.

 Swarfy.
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Online berger

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Re: cylinder head
« Reply #26 on: 09.04. 2020 19:55 »
swarfy one thing for sure my old inlets are correct and I will put the 9" exhausts in , very strange the other sizes , the exhausts at 9/1/16th have been in and never changed while I have owned the bike up until I changed all 4  saving mine for the berger build, its a mystery to me but I am pretty sure my original inlets will sort the job, I will find out in the coming days cheers
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Re: cylinder head
« Reply #27 on: 13.04. 2020 20:01 »
said I was thick , lost the plot somewhere. it hit me straight away when building up the two rocker boxes regarding the spindle washers *doh* two are smaller hole size *red* , amazing what you forget when the pubs more important *beer* . so now I have the berger build box done and have also got the lovely jubly home made gaskets fixed to the underside of the rocker box that is going on tomorrow with the old CORRECT push rods, and of course two different tappets because the others were a bit fed up, after being at the wrong angle. still confused as why the push rods I had put in were 8/1/8th inlet and 9/1/6th exhaust *conf2*
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Re: cylinder head
« Reply #28 on: 14.04. 2020 19:05 »
betsy has now got her lid on *yeah* the photo just about shows the difference 1/16th of an inch makes on push rod length regarding angle of inlet rocker, on a previous post I could only get fresh air through the gap of rocker arm and spring keeper and found it had made a mess of the two tappets - valve tops were ok they must be well ard *bash*.I have learnt a lot with putting in what I thought were A7 push rods on the previous top end build.
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Online Rex

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Re: cylinder head
« Reply #29 on: 15.04. 2020 09:29 »
Five minute job on a mill. Goop of some sort may work but doing it properly will last forever.
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