Head & barrel cleaning etc.

[steve452]

Need a bit of advice from you guys in the know.

1) Is it necessary to always hone the barrels after a rebuild? The engine is a Z1-B and just over 45 years old but had only done just over 22,000 miles when I stripped it down in 1977. I have reused the original pistons and rings which are all still in spec and look to be in good condition. I have never honed barrels before and am loath to perform a task unless required. I appreciate that the honing will aid oil adhesion on the barrel walls but are there any other benefits? The barrels don't look particularly glazed and have no obvious marks that would cause concern. Any opinions on this would be very welcome.

2) I'm intending to clean the head in my ultrasonic cleaner. Temp will be 80 degrees and I will probalbly run 3 cycles of 20 minutes each with a clean water bath between each. I have a compressor and air gun so will be able to blow out the oil pathways etc. after an initial rub down with the Sporting Life. Can anyone suggest any reason this would not be a good idea (i.e. valve guides dropping out etc), or is it an easy way to get some of the inaccessible gunge out from the threads and fins, which is why I intend to do it in the first place. I do not want to go down the vapour/aqua blasting route as I want the bike to look like exactly what it is i.e. a 45 year old Z1-B, but just cleaned up a bit. Basically I want to retain the patina on the engine as far as is possible.

[zed1015]

You only hone if you are fitting new rings but you may be taking a gamble with the original rings after all that time even though they are in spec etc.
50/50 whether you pull it off.. Fingers crossed..
Cleaning with the process you describe won't be a problem..

[ADRIAN H]

You only hone if you are fitting new rings but you may be taking a gamble with the original rings after all that time even though they are in spec etc.
50/50 whether you pull it off.. Fingers crossed..
Cleaning with the process you describe won't be a problem..

+ 1 Rob is the Guru.

[steve452]

I'm guessing you're alluding to a possible ring snapping. Does the metal degrade that much after 45 years? Up until 3 months ago the rings were still on the pistons and in the bores as I rebuilt the engine in 1980 but didn't carry on with the rest of the bike.

If there is a substantial risk then I'll go the new rings route but we are talking another £200 odd. I do appreciate the cost of a potential rebore and having to buy a ring set anyway, together with piston(s) and the cost of the engineering works, so is a failure that likely?

Obviously I will not hold you to anything you advise as this is my decision. Considering I've already spent well over £5000 on the rebuild so far it's a drop in the ocean but I don't particularly like spending money if unnecessary as I'd rather spend it on fuel for my other baby, a 350bhp Ninja H2 (rather thirsty at the best of times).

Any further comments you have will be much appreciated.

[zed1015]

No! not snapped rings.
Just that the rings could have reduced tension and lost some of their spring due to being sat in the bores for so long and so won't seal as they should.
£200 saved now "could" be £200 plus the cost of gaskets and time later on.
As stated it's a 50/50 chance and you won't know until it's running.

[steve452]

Well! I'd consider that very sound advice. As you say, I won't know until the mill's running so I think to eliminate the risk new rings are the way to go. I think I was just using you as a sounding board as really I had more or less made up my mind to replace them. I have watched a few LubeToob videos on honing and it seems to be fairly straightforward. Any advice on pitfalls to watch out for?

Many thanks for your very speedy reply. Your advice is very much appreciated.

[zed1015]

Getting the correct angle with drill powered stones can be tricky if you haven't done it before (and even when you have)
You need an angle no steeper than 45 degrees which is achieved be controlling hone speed and stroke.
For what it will cost for the hone and stones and then the chance of not getting it right i would take the barrels to an engine reconditioners and get it plateau (cork) honed professionally which will probably cost less.
This will pre bed the bores and allow a better seal from day one.

[steve452]

Rob, many thanks for that. Looking online and researching the various options I'd like to try and do it myself with a Flex-Hone Silicon Carbide tool (I'm all for learning a new skill if I believe it's within my limited capabilities). The tool is self-centering so even I might not be able to f**k it up. It's manufactured by BRM who apparently pioneered plateau honing in the early 60's. The closest I can get to the Z1 bore of 66mm is a 67mm, which will be oversized anyway as their nominal tool sizes are smaller than the actual tool diameter as the tool has to be larger than the bore it's honing. The only problem is the grit size I need. The "Standard" grits they list are 120, 180, 240 & 320. I really don't want to buy multiple tools so do you have any opinions on the best grit size? I'm leaning toward the 320 as it might be the best option for a ham-fisted fettler such as myself. I'll take some before and after pics to let you know how it went.

[chrisu]

You only hone if you are fitting new rings but you may be taking a gamble with the original rings after all that time even though they are in spec etc.
50/50 whether you pull it off.. Fingers crossed..
Cleaning with the process you describe won't be a problem..

^^^ This

[zed1015]

Those ball hones are better for de-glazing than the 3 legged type and easier to use too.
Much less chance of having a f*ck up.
Every shop and engine builder has their own take on the finished grit but getting the cross hatch angle is more important.
Once done, wash out the bores with soapy water not solvent and wipe out with paper towels until they come out clean.

[steve452]

Many thanks. After posting my question re grit grade I got a call from Phil at Pacehigh who are the UK distributors for BRM, and who I'd sent a quote request form off to. He asked a lot of questions about the application, liner and ring material etc and in the end suggested a 240 grit as the most appropriate. He thought a 320 would give a near polished finish which would not really allow the new rings to bed in properly.

So all now sorted. Will post pics when I'm done.

BTW the rotor bolt issue has now been sorted as well. Combination of heat, Molyslip & TC tap went like a dream.

[needaz1100r]

You only hone if you are fitting new rings but you may be taking a gamble with the original rings after all that time even though they are in spec etc.
50/50 whether you pull it off.. Fingers crossed..
Cleaning with the process you describe won't be a problem..

^^^ This

Also agree with this except I wouldn't put it as high as 50% it won't smoke.

[steve452]

My first ever attempt at plateau honing using a 240grit TC Flex-Hone. Before and after pics.

[zed1015]

Looks like you got the hang of that