cylinder head

[0116harley]

Hi all
Need a bit of advice on this one, ive got a cylinder head i want to fit on my A10.The problem is there are some deep marks which looks like someones had a go with a file, the deepest mark is at a guess about 15 tho deep.Asked at the local motorcycle shop about this they suggested to use a metal glue.Not sure about this.               cheers neil

[Beezageezauk]

Yes Neil,

It's sometimes referred to as Plastic Metal.  Apply it like putty and after it sets you can file it to shape.

The instructions often say that it can be drilled and tapped but I've never been brave enough to go that far with it.

Read the instructions before you buy it and satisfy yourself that it's fit for purpose.

Beezageezauk.

[wilko]

J B weld is your friend, nothing else will do!

[t20racerman]

Alternatively, strip the head and get 15 thou skimmed off the head surfaces.
Also, don't use bought in gaskets as they all seem to be rubbish - buy some 0.8mm gasket paper and cut your own. Make them a bit wide and trim to size after assembly with a sharp blade.

[bsa- bill]

Also, don't use bought in gaskets as they all seem to be rubbish - buy some 0.8mm gasket paper and cut your own

Yep, I totally agree with that

[0116harley]

Thanks for the advice guys. Think i'll get the surfaces skimmed seems more of a permanent fix
cheers neil

[manosound]

Unless you are worried that you might not be judged a 94 at the next Concours d' Elegance, in my opinion the skimming isn't worth what it's going to cost. After all,  the objective is to hold in the oil, and JB weld would serve that purpose. Hell, maybe even a thick slather of Permatex would do. Back to the JB Weld, it's black and should not show up on the painted cast iron head. Anyway, unless you do the vibration-damped head steady (described elsewhere on the forum) , chances are you'll leak a little anyway. Finally,  maybe you won't have to remove the valves.

Richard L.

[chilblayth]

yes  i agree !  jb weld or similar will be fine i think , i remember a head repair on an xt500 where someone had been porting overenthusiastically and gone through into rocker area , oil was being sucked into the inlet port !!!!!!    looked like a james bond smokemaker       turned up a alloy base plate secured it with ARALDITE    and it was perfect      these modern epoxy adhesives are really  good 

[BSA_54A10]

The magic goop is Davcon.
It was designed for temporary repairs in places like ship engines and mining equipment.
Not cheap but works perfectly.
I have used epoxy putty sold as a radiator repair for fixing holes in crankcases for years and it works very well .
SR500's have a bad habit of popping the brake lever toe through the case if they fall over.
I had one repair last for 11 years of abuse as a courier bike.

[beezermacc]

I definitely would not skim the top of the head. This will alter the angle of attack between the rocker arm and the valve stem. It may not make a lot of difference but its surprising how one thing leads to another.........

[muskrat]

 G'day all,
             JBWeld would be my choice. But if you do remove the guides to skim the head I'd be replacing them as well. And the amount taken off the head and/or box can be compensated by using a thicker copper gasket from Lanni. http://www.coppergaskets.us/MCExamples.html
Cheers

[bsa- bill]

Well it will do that to some degree right enough beezermacc, as will using thicker gaskets, a compression plate, skimming the other side of the head and changing the camshaft or using reground followers.

Going off at a tangent here but thinking about compression plate (surely that should be decompression plate) will it have the effect of softening the cam

[0116harley]

Thanks for all the feedback on this. Change of plan,never used j b weld or any kind of metal glue before. So i'm gonna give it a go. It does save all the hassle of taken the guides out. Maybe a good idea to wait till the weather warms up. As i should imagine this stuff dont work that well in freezing conditions. And the wifes getting fed up of bike bits in the house (women i'll never understand them).
cheers neil  

[rockthedog]

yes jb weld did it for me been ok for last 5 years now

[manosound]

Neil,

Test a small amount (say 1/2 teaspoon) of the JB Weld on a piece of cardboard set to cure outdoors. Being a two-part filler, low temperature should not prevent curing, just make it take a long time, but probabaly a lot shorter than waiting for the weather to change. The manufactturer suggests a heat lamp to speed things up.

Richard L.

[0116harley]

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

[manosound]

Neil,

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


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

Richard L.