Here we go! Restoring 576/748

[markb]

Mark
I hope the pic of 1553 with the stand down is correct. It doesn't look repaired unless it was all on the back side like mine was on 576. Don't feel pressured to get 1553 apart on my behalf. I have lots of other things to do like get the motor torn down.

The weld doesn't look repaired at all.  And there's no pressure, from you anyway.  I need to get it torn down so I can get mine repaired too so I can get the frame to the painter.  And I want to check out the cylinder on 1553 so I need to get the motor out but before I tear down the motor I want to put it 97's frame so I can do your idea of putting on the exhaust pipe to check out the location.  I hate to say it but thinking these things through is half the fun for me. 

[Wayne]

Started to take down the engine today. All went pretty well except I couldn't get the head separated from the cylinders. I have been faced with this challenge many times over the years and resorted to methods such as cranking the engine with head bolds loose, introducing compressed air to the cylinders...you get the idea. Anyway, I lifted both the cylinders and head together to see if I could get a better angle at breaking them loose. No such luck and I'm scared to death of doing damage to one or the other. I did remove the 4 philips screws from under the pucks. (I didn't even have to make a narrow socket as I have seen others do for the outside ones. Some Liquid Wrench, tap tap and out they came) Also got the one at the rear. If anyone has any tricks up their sleeve to separate the head from the cylinder I'm all ears.

Update:
I got the head off. Having learned over the years that hammers just break things, I knew I had to find a way to get a wedge between the cylinders and the head. The only area I could see that seemed robust enough was at the rear of the head where the bolt went through to the cam tensioner area. I used utility knife blades for the job, tapping them in gently. It took 3 before I could hear the satisfying sound of the gasket letting go. wheeew!   With my wedges driven deeper I used a hardwood dowel and hammer to gently tap the head from it's dowels on the other side.

I noticed a date marking on the rocker carriers so I took a shot. May or may not be of interest. :looks like 44.5.8 on both carriers.

[kp]

For those that don't know of this type of dating system used by the Japanese bike manufacturers, they used a dating system based on the reign of the emperor in power at the time. Date is 69 May 8 or 69 August 5. I think the Japanese used US system of writing dates.
Emperors reign from 1924 to 1969 (If memory serves and I'm feeling lazy so won't look it up). Always add 1 extra to the reign so 1924 to 1969 is 1969- (1924 +1) = 44years
I' not sure about the 5 and 8 In Oz we would say 69 August 5. You have a different way of writing the date

[Wayne]

KP, I'm just blown away that the dates are still intact after all these years. I'm going to do my darnedest to keep them intact throughout the rebuild. I touched one and it looks like it may have smeared a bit.

[Steve Swan]

This is the 3rd or 4th time i've revisited this topic and it seems to be one of those things i cannot commit to my ever aging brain/memory.

I'm hoping Chris will step in, as i tried writing from memory once before on the BB about this dating system and thoroughly butchered the topic.

The dating system is from the Japanese Showa period http://en.wikipedia.org/wiki/Sh%C5%8Dwa_period and dates the reign of Hiro Hito (Emperor Showa), 1926-1989 - http://en.wikipedia.org/wiki/Hirohito

As KP said, the dating system starts in 1926.  Hoping Chris chimes in.............

I do know this topic is somewhere in the BB.........

[Wayne]

Aside from the system itself guys, is it common to find the stamps on the various engine parts as well preserved as they are on 748? I'm just surprised they haven't washed/worn away over time.

[Steve Swan]

My experience, it is common to see the date marks on engine internals.  It is surprising how well they remain intact and yet how vulnerable they are to being wiped away.

[kp]

The Showa dating system must be (1926 -1)+44. I said 1924. I knew it was something along those lines  . Yes it is amazing about those dates The dates on the set for E894 are 44-5-21 so the US date system is used. Interesting. A lot of the Kawasaki parts use the Showa dating method

[Steve Swan]

In the case of Emperor Showa, what's amazing is the era of history he helped create. He was believed by many to be a divine god.  Sorry Wayne, i am hi-jacking your thread........ 

[Wayne]

No problem Steve. It's all interesting stuff.

Pulled a bit more apart today. I feel and hurt my back the other day so I had to cut it short.   I did get the alternator cover and alternator off. The wiring is like dry twigs! Going to have to do some work to fix that harness up. Just moving it breaks it open and none of the connectors will come apart. They are hard as rocks. Starter is off. Nothing eventful there other than the cable is just so so in my opinion.

Pulled the pistons from their perches. Took a quick measurement. All are well within spec. The only bit of concern is a broken compression ring on #1. It's broken into 3 pieces. I checked the ends for "polishing". No evidence of any even under magnification so I'll rule out tight end gap. I don't have feeler gauges narrow enough to check the ring  side clearance. If I re-use these pistons (which I doubt) I will be sure and do it. I suspect #1 got lean at some time in it's life causing detonation.

I said IF as I'm leaning on going to the first OS. It just makes sense to be when you have gone this far, to start with a perfect bore and a nice new set of slugs.

[hondasan]

The way it was explained to me by a guy in the UK (who has been riding Hondas for FIFTY years now) was that the system is related to year of reign of the Japanese Emporer. Apparently his reign commened in 1925 (year "0"), hence 1969 is the 44th year of "his" reign, with the month / day numbers appearing in US date order.
So, just add 25 to the year number....Date of the carrier in question is 44.5.8, which becomes 1969, May 8th.
I have found these "showan" dates on quite a number of engine components now, including cylinder barrel top fin, clutch baskets, cam carriers, inside valve covers,... Not always on the same parts within different engines though. Just today found them on a set of rear brake shoes in a '71 750K2 ("46" being the showan year in that case).

Whilst the ink is reasonably robust, must be to have lasted 40+ years so far, solvent cleaning will certainly take it off.

Happy New Year to you all - Chris R.

Having posted the above, KP very kindly did some research and established the facts wrt the dating sytem...

In fact, Hirohito's reign was from 25 December 1926 to 7 January 1989, with 1926 (all 6 days of his reign during it) being year 1, 1927 being year 2, etc, until we get to 1969 which is year 44.
The simple ruse of adding 25 to the year number works, but not because that is the year of his accession. Detailed explanation of the way the Japanese calendar system works can of course be found in great detail on the internet for those who want to know more. 

Thanks again to KP for setting the record straight.   - Chris R.

[ashimotok0]

I  spent the last month searching for the silicone coated, woven glass, braided sleeving (three sizes) for the alternator harness, oil pressure switch cable and the points sub loom for the Sandcast / early K0. I finally have samples and its a pretty good match the original in white. The only gripe I have with it is that the silicone coating is only a thin coat so I have treated it with non-acetic acid based white silicone compound and it is now closer to the original. I have also sourced clear heatshrink for the ends of the alternator sub harness. I appreciate that the ends were originally wrapped in clear tape of some kind but the heatshrink looks pretty good, even though  normally hate the use of heatshrink on wiring looms. I found that the Yamiya harness is not a good replica of the Sandcast/early VIN K0 and the same for the earth cable. I have done a post mortem on the battery earth cable too and replicated the multi  strand inner/braided outer for the earth cable which turns out a round section rather than the 'flat' look of the Yamiya harness (which also  has incorrect crimped terminals too instead of soldered, as original). Samples of my 'experiments' are being sent to ChrisR this week - If Chris thinks they look OK then that's good enough for me!! The only thing I am re-using is the black thin walled rubber tube fitted over the white braided glass sleeve on the alternator sub-harness.I am sure this can be found but people don't want to sell you a foot of it (as I have found with the glass braided sleeving!!)

I am also experimenting with renovating the original coils on the bike ( stripping back plastic to replace HT leads and then creating a mould to reform the plastic covering (MAD I KNOW!!). I am determined that my K0 will have as many of the original electrical parts on it, refurbished as best I can. I can't see the point in paying top prices for repro stuff that is not even faithful to the original and also  it generates a great deal of satisfaction doing it.


http://www.yamiya750e.com/index.php?main_page=product_info&cPath=37_99&products_id=485

BTW my coloured wiring on VIN 1010382 is printed 'Sumitomo 1969'

Cheers and a Happy New Year to you all!!

Ash D

Steve- I only put this here because of Wayne's comments on the alternator wiring. Please move as you deem fit!!

[kp]

Wow!  I'd be interested to see how this all turns out. Thanks for the update Ash. KP

[Steve Swan]

As an aisde, Yamiya does sell the alternator harness.

[Wayne]

Took a few more bits and pieces off my motor. Still a bit sore from my fall so I'm going slow. I tackled head stud removal as I have decided to follow Mark's lead and install APE studs. After reading horror stories about removing this pesky studs I firsted squirted on some Liquid Wrench and let them soak overnight. Next day I just clamped on the vice grips and the first one came loose with little effort! I thought, this can't be! Sure enough, one after another, Liquid Wrench, tap, tap with a light hammer and they came free with just vice grips. As always, my luck ran out when it came to the last four, front and center. At that point I introduced some heat from my heat gun. After a couple of tries I got 2 more. I'm now down to the 2 front inside studs and I can't seem to budge them. I have tapped on them with my hammer, rang them hoping the harmonic frequency might loosen their hold, heated them multiple times with my heat gun, used opposing vice grips, vice grips and a wrench on the stud double nutted. No luck!  

I read about bending the studs and removing them that way but that makes me a bit nervous. I'm getting a good bite with 2 vice grips and I have always had a good feel for when things will twist off. I don't want that to happen.

I'm thinking what I might try after letting them soak again for a while and freeze my Vice Grips. After heating the case I'll clamp my frozen Vice Grips to the stud. Perhaps we'll get enough shrinkage on the stud to help things along.