Topic: Sandcast #97 restoration

[markb]

DOH!!  You're right, there is.  I don't know why I didn't think of that. 

[HondaMan]

DOH!!  You're right, there is.  I don't know why I didn't think of that. 

The early ones (K1-K2 engines, not sure about sandcast) were 3.2x18mm O-rings for the main oil galley. The later ones were 3.5x18. The groove around the dowel there got wider, later.

About the clutch plate tabs: the outer diameter of the clutch basket changed a bit several times over the years. The longer ones work when there is no band around the outer edge, like many pre-K3 engines had. Those shorter-tabbed ones had to slip in under that band.

The shifting improvement thing: look closely at the angle of the "ramps" in the shifter drum(s) and the width of those drums around the fork pins. These also changed several times. Early ramps were straight and pretty "steep" angles, which made for stiffness when hot or when the clutch dragged a little. Later ramps had non-straight ramps, especially around the 1-N-2 shift, to make a more 'notchy' feel to the shift. It's hard to see the difference, but interesting to see how well it worked.

[markb]

Thanks again for the info.  I really enjoy the extra facts.  I will take a look at my shift drums.

[markb]

I carefully compared all four of the shift drums that I have and could not see any differences in them.  They’re all sandcast ones and the change must have come later.  At least I know the one I have in there is correct.

I’m ready to button up the cases but before I do here is a pic of another distinction.  The bearing on the primary drive on the clutch end of the main shaft  is smooth on engines up to 5306.  After that they have a groove.


Finally together!  I had all the bolts sorted and ready to go so it went real well.  Definitely not something you want to stop in the middle of.


I’m sure you guys all know this but you want to make sure you have this cable clamp on before you put the engine in the frame.  You can’t remove this bolt when the engine is in the frame.  Don’t ask me how I know.

[HondaMan]

I carefully compared all four of the shift drums that I have and could not see any differences in them.  They’re all sandcast ones and the change must have come later.  At least I know the one I have in there is correct.

I’m ready to button up the cases but before I do here is a pic of another distinction.  The bearing on the primary drive on the clutch end of the main shaft  is smooth on engines up to 5306.  After that they have a groove.

Yep, the clutch bearings would pull up against the primary gears, sliding right out of the cases, when the bikes were pressed hard (like Saturday night drags). Then the engine made a whining, scraping noise, and grindings showed up in the oil filter. Then you would take the engine apart, and MAYBE find where the bearing was rubbing, maybe not, inadvertently line it all back up and reassemble...then the bike would come back again later, same issue. It took us several 'trips' like this on the first one Jimbo saw in Peoria, to figure out the bearing was walking.

In my imagination, I see Honda installing the retainer later to prevent the side-load from the clutch lifter as an engineering change, inadvertently 'fixing' the above problem. We didn't see it but on the one bike there, though. Jim's smart solution was to add a shim to the other end of the mainshaft, by the far bearing, to prevent the tiny bit of back-and-forth shaft movement that happens from the shaft twist and/or clutch "push". This seemed to fix the bike.

[markb]

Yep, the clutch bearings would pull up against the primary gears, sliding right out of the cases, when the bikes were pressed hard (like Saturday night drags).

Fortunately this one won't be pressed hard or often for that matter. 

[markb]

Here’s a very early distinction.  According to the early parts books the engines up to 219 had an M8 x 80mm bolt at this location on the back of the case.


From engine 220 the bolt was change to a special M10 x 82mm bolt with a flange head.


The early sandcast engine number pads were 11mm wide.  At some point they changed to 19mm.  Notice the square near the number pad.  I’m not sure if that went away with the wider pad or not.


Also the very early cases had no casting dates.

[Old Scrambler]

Thanks, Mark.............great work

That bearing experience happened to my bike after the broken cases (chain) were replaced with die-cast units.  American Honda took my bike from a dealer on Hawthorne Blvd in LA and brought me a smoother shifting and faster bike about 10-days later. They said they wanted to tear-down the motor because it had about 18,000 miles on it in late 1970.   

[HondaMan]

Thanks, Mark.............great work

That bearing experience happened to my bike after the broken cases (chain) were replaced with die-cast units.  American Honda took my bike from a dealer on Hawthorne Blvd in LA and brought me a smoother shifting and faster bike about 10-days later. They said they wanted to tear-down the motor because it had about 18,000 miles on it in late 1970.   

Wow! Did Honda actually swap engines (or bikes) with you! I heard of 2 other guys this happened with, one in Chicago area and one in St. Louis, MO. They were both tourers, and by 20k miles had thrown chains and had filings in their cases. Honda swapped the engine in the St. Louis bike with a diecast engine, and replaced the whole Chicago bike with a new (diecast) bike.

[MoMo]

Thanks, Mark.............great work

That bearing experience happened to my bike after the broken cases (chain) were replaced with die-cast units.  American Honda took my bike from a dealer on Hawthorne Blvd in LA and brought me a smoother shifting and faster bike about 10-days later. They said they wanted to tear-down the motor because it had about 18,000 miles on it in late 1970.   

Wow! Did Honda actually swap engines (or bikes) with you! I heard of 2 other guys this happened with, one in Chicago area and one in St. Louis, MO. They were both tourers, and by 20k miles had thrown chains and had filings in their cases. Honda swapped the engine in the St. Louis bike with a diecast engine, and replaced the whole Chicago bike with a new (diecast) bike.

Mark, also happened with a friend of mine who was touring cross country on a 69 750.   Broke down in the middle of nowhere Utah and Honda replaced the motor...Larry

[HondaMan]

Thanks, Mark.............great work

That bearing experience happened to my bike after the broken cases (chain) were replaced with die-cast units.  American Honda took my bike from a dealer on Hawthorne Blvd in LA and brought me a smoother shifting and faster bike about 10-days later. They said they wanted to tear-down the motor because it had about 18,000 miles on it in late 1970.   

Wow! Did Honda actually swap engines (or bikes) with you! I heard of 2 other guys this happened with, one in Chicago area and one in St. Louis, MO. They were both tourers, and by 20k miles had thrown chains and had filings in their cases. Honda swapped the engine in the St. Louis bike with a diecast engine, and replaced the whole Chicago bike with a new (diecast) bike.

Mark, also happened with a friend of mine who was touring cross country on a 69 750.   Broke down in the middle of nowhere Utah and Honda replaced the motor...Larry

Yeah, Honda was real guarded about the early failures, very afraid to 'lose face' in the marketplace. It led to a lot of folks 'spreading the word' that Honda was committed to the bike's success in those days, which was a completely new 'thing' coming from Japan back then.

[MoMo]

Thanks, Mark.............great work

That bearing experience happened to my bike after the broken cases (chain) were replaced with die-cast units.  American Honda took my bike from a dealer on Hawthorne Blvd in LA and brought me a smoother shifting and faster bike about 10-days later. They said they wanted to tear-down the motor because it had about 18,000 miles on it in late 1970.   

Wow! Did Honda actually swap engines (or bikes) with you! I heard of 2 other guys this happened with, one in Chicago area and one in St. Louis, MO. They were both tourers, and by 20k miles had thrown chains and had filings in their cases. Honda swapped the engine in the St. Louis bike with a diecast engine, and replaced the whole Chicago bike with a new (diecast) bike.

Mark, also happened with a friend of mine who was touring cross country on a 69 750.   Broke down in the middle of nowhere Utah and Honda replaced the motor...Larry

Yeah, Honda was real guarded about the early failures, very afraid to 'lose face' in the marketplace. It led to a lot of folks 'spreading the word' that Honda was committed to the bike's success in those days, which was a completely new 'thing' coming from Japan back then.

Agree,  they were on a mission to cut into(and dominate) the market.  Did a darn good job at it, didn't they?  I can't remember how many 750 cases I replaced,  warranty reimbursement time for a flat rate mechanic was horrible but after doing several I was able to get close to the time....Larry

[HondaMan]

Thanks, Mark.............great work

That bearing experience happened to my bike after the broken cases (chain) were replaced with die-cast units.  American Honda took my bike from a dealer on Hawthorne Blvd in LA and brought me a smoother shifting and faster bike about 10-days later. They said they wanted to tear-down the motor because it had about 18,000 miles on it in late 1970.   

Wow! Did Honda actually swap engines (or bikes) with you! I heard of 2 other guys this happened with, one in Chicago area and one in St. Louis, MO. They were both tourers, and by 20k miles had thrown chains and had filings in their cases. Honda swapped the engine in the St. Louis bike with a diecast engine, and replaced the whole Chicago bike with a new (diecast) bike.

Mark, also happened with a friend of mine who was touring cross country on a 69 750.   Broke down in the middle of nowhere Utah and Honda replaced the motor...Larry

Yeah, Honda was real guarded about the early failures, very afraid to 'lose face' in the marketplace. It led to a lot of folks 'spreading the word' that Honda was committed to the bike's success in those days, which was a completely new 'thing' coming from Japan back then.

Agree,  they were on a mission to cut into(and dominate) the market.  Did a darn good job at it, didn't they?  I can't remember how many 750 cases I replaced,  warranty reimbursement time for a flat rate mechanic was horrible but after doing several I was able to get close to the time....Larry

Well, then, you beat me: it STILL takes me 2 days at least!

[MoMo]

If my foggy recollection works the time was 18.5 hours, which is two days of work Mark so after 40 years of experience you're right there   No way I could get close to that time at 66, I used to bust my butt back then and really made awesome money for a 20+ year old...Larry

[750K]

Subscribed, this build thread is so great. I don't know much about early 750's let alone sandcast models, so all this info makes for great reading. I love this forum!

[sanxa_]

What a great read - incredible work markb!

[HondaMan]

If my foggy recollection works the time was 18.5 hours, which is two days of work Mark so after 40 years of experience you're right there   No way I could get close to that time at 66, I used to bust my butt back then and really made awesome money for a 20+ year old...Larry

I think I'm getting slower, or maybe just enjoying it more? It takes me 3 days now.

[NobleHops]

Sorry for the blah blah, but as a noob I just discovered this epic thread and read it in its entirety tonight. I have learned a ton and you have raised the bar for sure. Thank you so much for all the effort that went into documenting this project and answering all the questions so patiently along the way. Much respect.

[markb]

Sorry I haven’t posted anything for the last month.  I’ve been busy but I managed to get a few things done.  I was working on my polishing and I found a guy who does great work.  He does the brushed look, just like I want it.  So I gave it to him to finish up so I could work on other things. 

The first thing I did was get the shift linkage area and drive sprocket reassembled.  The countershaft bearing holder was different on E100, it’s the one on the left.  You really have to make sure the small oil passages aren’t plugged up on this guy.  I soaked it in acetone three times and blew them out with compressed air until they came clean.


Here’s everything together.


I got stalled for a while because I couldn’t find the double spring washer.  I figured I would just buy a new one but they don’t exist anywhere anymore.  Fortunately I was able to locate mine.

E100 didn’t have a 16 tooth sprocket but I tracked down a nice replacement.


I didn’t install the oiler.  The hole in the shaft is plugged to disable it.  I have the NOS parts in case me or the next owner decides they want it to be that correct.

[markb]

On to the pistons.


I had sets that had different numbers on them (2, 3, 5).  These from an early sandcast have 2’s. 


I’ve never had much luck installing the cylinders by pushing the rings in with my fingers.  Seems like every time I do it that way I always hear a click on the last push and have to pull the cylinders off to make sure I didn’t break a ring.  One time I did.  I’ve used hose clamps too and they just barely cover the rings and are a little touchy so for me they just work OK.  So I made up a set of ring compressors.  It’s just an improvement on the hose clamp idea which I have done before too.

Here’s one of the compressors in place.  I snug up the hose clamp and back it off one turn and they slide perfectly.


Ready to drop the jugs on.  By the way, those are all new stock studs.  I was thinking of using APE's but decided to keep everything correct.

[MoMo]

Clever design and very simple ...Larry

[iron_worker]

Agreed. I like it a lot. Might be a neat thing to sell and make a few bucks.

IW

[markb]

Now for the cylinders.  The first thing I do is put some spacers under the center pistons to hold them straight.


Here I’m ready to slide the cylinders over the pistons.


And here’s the cylinders in place.  The compressors worked pretty well.  It’s a little tedious getting them out before you go the last inch.  But for me no worse than trying to coax the rings in with your fingers.  The only downside was the outside diameter of the ring halves was a little small so I had to be careful not to let them slip into the cases.  If I were to do it over I would definitely make them bigger.  Other than that the cylinders went on real smooooth.

After that it didn’t take long to get the head on and torqued down.  As you all know torque the 8mm nuts (in correct order) before the 6mm screws.  I’ll let them sit a week or two and then break them loose and retighten.


One interesting note here.  Sandcast engines up to 1106 have the special 6mm cross hex flange screw at the rear of the head as well as the four under the cam towers.  After 1106 the rear one is changed to a hex head.  E100 came with special “8” flange hex heads so even though that’s not what the parts book says, that’s what I’m putting back.


So that pretty much catches me up with my posts for now.  Not much for the last month or so but at least it’s coming along.

[jerry h]

Beautiful engine!  I like your ring compressor idea.  Always learn something by stopping by.  Fantastic write up.

[Garage_guy_chris]

awesome thread. These early sandcasts are something else. I thought my K4 was a lot of work = foot in mouth...   I have to admire the time and patience that has gone into this bike. Cant wait to see the final product.