1978 r100rs rebuild

Safety wiring

Mr. Spackled...I could sit here all day writing about the proper way to safety wire and it would do no good. To do it correctly requires practice. I did give two sources for how to do it right. There was no need to insult me.

That said, the previous post does illustrate the proper way to safety wire. The OP said the bolts were drilled only on one side. That is not unusual. The procedure is the same, just as has been said. If one bolt begins to loosen, it will tighten the saftey wire and can not loosen any more. The other problem with the safety wire in the photo is the number of twists on the wire between the bolts. The photo is very clear showing this. If there are not enough turns, the wire will stretch. If there are too many, the wire will be under too much tension and will be prone to break. The proper number of twists varies with the diameter of the safety wire. Again, the FAA procedure book AC43-13 1A and 2 gives these requirements.

I also stated what another post said...I've never seen a properly torqued fastener come loose, provided there is no problem with the assembly that the fastener is holding together. He is 100% correct in his statement.

I do not post anything giving advice or opinions on a subject I know nothing about. As the military A/C mechanic said, I, too, have spent years working on aircraft. My work was limited to agricultural airplanes with a total rebuild of a crashed 1959 Piper PA-18A (a Super Cub designed to be a crop duster also) and have built a Van's Aircraft RV-6.

Mr. Spackled, I believe the you have the better idea...Clean threads, good undamaged fasteners, and Blue Loctite. That is all you need. I was just trying to help someone avoid doing it wrong and having an needless failure on down the road.

You are doing a great job with your restoration. I'm sure it will give you many trouble free miles of enjoyment.

Safety Wiring

Dap_Spackled said:

Whoa, Flywheel Boy. Why don't you explain the better way of doing it.

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Hey, Dap!

First I would like to say you are doing an awesome job on that R100RS rebuild, a model that is very near & dear to me.

It is quite apparent that you are a very capable mechanic and one who strives to do everything correctly. Your work is very clean.

Having said that, I will flatly state that:

The safety wiring job your P.O. did on the flywheel bolts is, without question, the single sorriest attempt at safety wiring I have ever seen, or ever expect to see! It is a total and complete joke.

This absolutely does NOT reflect on you! How could it? YOU didn't do that!

But I have to come to the support of copandengr on this one, having read both his initial post and his most recent one. The gentleman is correct.

I believe I have some basis for an opinion on this as I have spent years maintaining a private fleet of piston and jet warbirds and corporate turboprop and jet aircraft and hold a current A&P certificate with Inspection Authorization. I have safety wired all kinds of stuff for years and continue to do so as part of my daily work.

I looked all over the net for some GOOD examples of how to do this. The references that copandengr posted are fine but most folks don't have a copy of FAA AC43.13-1B at hand.

It CAN be found online (as a PDF) here:

http://rgl.faa.gov/Regulatory_and_G...lar.nsf/list/AC 43.13-1B/$FILE/Chapter 07.pdf

(For safety wiring methods and practices, look at Chapter 7, Section 7.)

Unfortunately, I did find MANY examples/photos of half-assed safety wiring jobs on the net - and most of the crappy ones were posted on motorcycle sites!

Dap - I know this is a moot point in your case because you already explained that you intend (or have already done) to torque the bolts properly and use Loctite. This is just fine.

One of the VERY BEST reference documents I have seen anywhere on fasteners AND safety wiring is Carroll Smith's book, "Nuts, Bolts, Fasteners and Plumbing."

http://www.amazon.com/Fasteners-Plumbing-Handbook-Motorbooks-Workshop/dp/0879384069

It is easy to find, inexpensive and just OUTSTANDING, PRACTICAL material for any mechanic. There is a lot of material in that book that a lot of aircraft mechanics SHOULD know but many don't.

Anyway, keep up your excellent work and don't pick on copandenger - he speaks the truth!

Thanks for the comments. BTW, with your advice, I just ordered Carroll Smith's book at Amazon. I have a HHHUUUGGGEEE collection of technical reference books on many subjects. My occupation for 36 years has been Information Technology, and I build computers. I have never been a professional mechanic, but I am a pilot. I also have 45 years experience with riding, racing and wrenching in every 2-wheel endeavour except hill climbing (not alot of hills in Florida).

Thanks.

Technical Library

Dap_Spackled said:

"... I just ordered Carroll Smith's book at Amazon."

Thanks.

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Dap,

As you obviously know already, having a good technical library is an enormous help.

I guarantee you will NOT be disappointed in this book!

Charlie

Cylinder Base

When I first pulled this engine apart, there were NO CYLINDER BASE GASKETS. And, yes, this is a '78 R100RS., but I was not the 1st person to have this engine apart I have read everything I can get my hands on from Snowbum, Anton, and others. I know that sometime in later '78, the cylinder base was cut for an O-ring, but this is NOT that model.

I did buy base gasket (a.k.a "shim") from from cycleworks. It is a compression lowering .5mm metal shim (aluminum, I think. I'd have to look again). I am hesitant to use it.

I have also read in several places to simply thin-coat the mating surface of the cylinder base with Threebond 1121. There were other gasket material options also. I have some Threebond 1194, but I will have to do more research to see if that is acceptable.

Has anyone else out there rebuild a '78 R100 motor without cyliner base gaskets? How did you do it?

Unless you're trying to "fix" something, there's no reason to use a gasket of any kind at the cylinder base. This guy has a pretty good visual on application of the liquid sealant to the base...he refers to Yamabond or Three bond 1209. I've also heard the product Permatex Ultra Gray.

http://www.gunsmoke.com/motorcycling/r100gs/sealant/index.html

RS Cylinder Base Gaskets?

Dap_Spackled said:

When I first pulled this engine apart, there were NO CYLINDER BASE GASKETS. And, yes, this is a '78 R100RS., but I was not the 1st person to have this engine apart I have read everything I can get my hands on from Snowbum, Anton, and others. I know that sometime in later '78, the cylinder base was cut for an O-ring, but this is NOT that model.

I did buy base gasket (a.k.a "shim") from from cycleworks. It is a compression lowering .5mm metal shim (aluminum, I think. I'd have to look again). I am hesitant to use it.

I have also read in several places to simply thin-coat the mating surface of the cylinder base with Threebond 1121. There were other gasket material options also. I have some Threebond 1194, but I will have to do more research to see if that is acceptable.

Has anyone else out there rebuild a '78 R100 motor without cyliner base gaskets? How did you do it?

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Dap,

I do NOT presume to speak with authority on the matter but I have had the cylinders off my second RS, a '78 R100RS (thirty years ago) and my current (1977) R100RS and I have never <personally> seen cylinder base gaskets on an RS.

My first RS (another '77 which I acquired in 1979) showed no evidence of having base gaskets either, as in "if they're in there, you can't see them."

The parts catalog (microfiche) doesn't show show any gaskets there, just the small O-rings for the top two studs and the one big one for the cylinder spigot.

I hear Twilight Zone music playing, Dap! I could be wrong but I am not aware of ANY R100RS model/year that ever used anything except the O-rings.

Better get the straight skinny on this from an expert on the topic, which I am not!

Good luck!

Recent experience...

No shim (base gasket) and no large 'O' ring. I have a late production 78 R100S I installed new pushrod seals in. I am the second owner but purchased it with 8700 miles on the clock so what I found is factory. Two small 'O' rings in the recess on each cylinder and a light coat of either Hylomar (factory goop) or something akin to RTV Red hi-temp sealant (what I now use). Put a little engine oil or heavy engine assembly oil on the pushrod tube seals where they sit against the block and the on the tubes on which they are installed so they "respond" during heat / cool cycles. None of my 3 77 RS have base gaskets...One is original.

OK. Now that is the kinda of help I am talking about!

Thanks, guys. No Gasket; just Goop.

and fwiw- other than head differences on the large valve S or RS models, the motor construction for all /7 vintage bikes are pretty much identical (not getting involved with cam differences here); no real need to distinguish between RS or other models.

Flash-Forward

I started this thread quite awhile ago, and I did not have the time to finish it.

I thought I would now post some pictures of the '78 R100RS as it stands today. I could say this is the final form, but we all know that is impossible. As I stated in the beginning, this was a rebuild, not a restoration.

I have all the parts and components to put this bike back as the '78 R100RS that it is, but I have chosen to build a daily rider in a standard R100 format. The bike runs great ----- with a few quirks that I will comment on in a later post.

WOW, nice bike.

Nice

The photos are great. You are to congratulated for the beautiful work you have done. May you enjoy many trouble free miles of fun riding it.

Sa-Wheeeeeet! ....Beautiful job, Dap.

Quirk

Thanks for the gracious comments.

Now, let me explain the quirk I am experiencing; and, hopefully, someone has experienced something similar.

This bike has a NEW Dyna ignition and NEW coils. However, the coils are for a 1964 Volkswagen Beetle. Experience and friends tell me they work superbly for the $19 each I spent. The timing is spot on --- statically and dynamically.

When the engine is shut off by the ignition switch, there is a PUFF or a firing of a cylinder. I guess you could cause it a backfire or a momentary single cylinder firing as in a "dieseling". A friend suggested that switching off the ignition causes the Dyna to dump the charge and fire the coils one last time. If I stop the engine with the kill switch, there is no immediate backfire thru a carb. However, I can then wait a few minutes and shut off the ignition ---- sometime without a pop, other times with.

Most of the time, it is just a "puff" or small backfire thru a carb (and which carb may vary). However, this AM, I noticed that the left carb had "slid" to the end of the short intake manifold track. There had been one instance very early on where shutting off the engine completely blew off the right carb.

I am suspicious of wiring, but I have no idea where to start the diagnosis.

backfire

Hey Dap- really nice job on bike! not really sure what may be causing misfire but I own a stock '81 RS and it does the same thing. I like the idea that the coils may be discharging when ignition switch is turned off. If this is the case then whichever intake valve is open may be seeing the fuel mixture between it and carb igniting, causing backfire. What I found that solves problem is shutdown procedure. I too shutdown with kill switch, but if I then return kill switch to run position and then turn off ignition I sometimes get backfire. I almost always get pop if I shutdown with ignition switch. But if I use kill switch to stop engine and then turn off ignition with kill switch still in kill position there is no backfire. I usually return kill switch to run position after I"m off bike. This may give fuel charge sitting behind open intake valve time to dissipate, although that's only a guess. Anyway that's what works for my bike, maybe it will work for you. Good luck and again really cool bike.

Michael
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78 R100S 81 R100RS

Bravo!

Very nice job. The more of these we can keep on the road, the better.

Road Trip

Well, let's see how well I have done on this re-build. I leave this week on a 2000 mile road trip from Florida to Hunter Island, SC and the USMC Recruit Depot at Parris Island. Then to Chimney Rock, NC with a continuation to Danville and Roanoke and Staunton, Virginia. Next stops will be Ashville, NC and Atlanta, GA. The Ga. Mountain Rally in Hiawassee, GA. Birmingham, AL and the Barber Museum. Lastly, Panama City, FL and around the gulf coast back to central Florida.

I certainly hope the bike holds up. Hell, for that matter, I hope I hold up too.

ENJOY.....

Road Trip

Dap_Spackled said:

I certainly hope the bike holds up. Hell, for that matter, I hope I hold up too.

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"Grasshopper",

If you have done your work with the correct attitude (and it looks like you have). The Road Spirits and the Gods of the RS Clan, will guide your journey ;-).

AND if something untoward should happen the "Airheads" are here .

radar