Good afternoon,
All the parts on our bikes are getting on a bit and many show the signs of a hard life and a bit of abuse. So it is with an A65 cylinder head I am fitting. How many time the head bolts must have been torqued down and undone. Perhaps over torqued or not torqued enough. So a series of photos following the repair and fettling of the head bolt surfaces on the head. On this head all of the head seat were worn and not level.
Head 1 Distortion of the bolt hole and cracking of the aluminium.
Head 2 Cracks filed out and a bolt in place to show distortion.
Head 3 With the head secured to a pillar drill a drill is used to centre the head.
More to follow.
Dave.
Head 3a End mill used to level the seats - it can be seen how bad they are once cutting starts.
Head 4 All of them needed doing - as the cutter remove material the unevenness can be seen.
Head 5 Looking a lot better for minimal material removal.
Dave.
Head 6 I am hoping the damaged one will look like a good one when finished.
Head 7 Even this one was not good - bolt to centre the head.
Head 8 Still a bit to cut.
Dave.
Head 9 A couple of old cable adjusters to hold a 'mould' in place.
Head 10 After applying the HTS-2000 - the bolt kept the hole open.
Head 11 After tidying with the end mill - not too bad?
I did not try to repair the hole but now the bolt is pulling down square it is a lot better than before.
This was my second attempt as my propane torch would not get the head hot enough so I had to get a 'Map' gas torch which burns a bit hotter so I am confident that it has worked this time.
Enjoy the photos.
Dave.
:) :) :)
Looks good Dave. You are definitely a couple of stepa ahead of me with this "stuff". Proof that it works and doesn't need all the kit that welding does.
Brill.
Mike 8) 8) 8)
My concern would be that using an endmill to spotface you dont get a flat face as there is relief on the cutter.
unless of course you have reground the cutter square
Hi,
Not being an expert in milling I enquired re the use of the cutter and it being 'flat' and the surfaces that I now have are far better than what was there before. The cutter looks square and although maybe far from ideal from a strict engineering viewpoint it looks quite good to me. The 'special' BSA washers from SRM sit perfectly on the new seats so I think it will do. If not I will know next time I have the head off and get it done properly. However, this could be several thousand miles if all goes well.
Dave.
Quote from: DAVE BRADY on 27 Jun, 2020, 21:11
Hi,
The 'special' BSA washers from SRM sit perfectly on the new seats so I think it will do.
Dave.
I take it the 'Special' washers are thicker Dave?
Morning Ian,
Yes they are a bit thicker and according to SRM they are to a BSA standard so that they do not distort. I would imagine that some of the damage that the head had was caused by incorrect washers. I have always just used what just seemed to be a thicker washer and I have some that are definitely not flat anymore. Hence proper ones from SRM along with new bolts.
If the washer is not up to the job then I suppose that this could result in ever so slight movement wearing the head and distorting the seats.
Hopefully now with flatter seats, proper washers and new bolts the head will be good for a while.
Dave.
Hi,
The washers in question are part number 02-0861, 0.750" O/D, 0.380" I/D and 0.380" thick. They are used to further improve the head gasket seal.
Best wishes...
Hi Bess,
The ones that SRM supplied are not as thick as 0.038" but probably half of this. I do have some of the thicker ones but they seem to lift the bolts and therefore reduce the amount of thread going in to the barrels. I think that they may be hardened to resist distortion.
Dave.
Hi,
Sorry should have read:
Part number 02-0861, 0.750" O/D, 0.380" I/D and 0.092" thick.
Best wishes...
Quote from: Bess on 28 Jun, 2020, 11:27
Hi,
The washers in question are part number 02-0861, 0.750" O/D, 0.380" I/D and 0.380" thick. They are used to further improve the head gasket seal.
Best wishes...
There's a service sheet identifying this.
Evening All,
Just an update on the head repair. Just over 200 miles covered so re-torqued the head bolts. The repair that I did is still looking good. I hope that I do not have to take the head off for some time so I am now confident that it will last.
Dave.