Anyone mention "D" engines?

[firstturn]

Just to let the people know that have been on the look out for me a Monark I purchaed one today.  Long time finding a complete bike.  A close Friend decided to turn loose of his and called.  Thanks to everyone who went the extra mile to try and find one for me.

Ron Carbaugh

[rob w]

Ron,

Monarks never had a "D" engine, the "D" engine came out after Monark had died. Some Monarks had "B/GS" engines.
I don't know everything, but that's what I believe is true, I was wrong once before.

Bob

[OUCWBOY]

Bob,
You were never wrong!?!?!!?!?!?!?!
I have heard that there are a few Monarks with D Motors in them. I don't know if they came that way or not, but check out this web site:

http://www.varberg.se/~igro/index.html

There is a registration page with bikes with D motors.

Donny Smith

[Bryson Williams]

Hi Donny, I was reading your post with great interest.  I looked at the ISDT Monark in the picture.  I counted the fins on the cylinder and counted 7 instead of 6 like on my "D" model motor.  


I was not aware that the "D" model motor came with a 7 fin barrel... I guess it's back to the drawing board for me.  I'm trying to learn as much as I can about the Pentons/Sachs and Monarks.

 I'm also looking for a 175 Sachs motor for my cross-country project this winter.

 Dirk Williams

[OUCWBOY]

Dirk,
I looked at that too, and to the best of my knowledge the D cylinders ALL have 6 fins. I have tried to ask, but have not gotten a reply. It is my understanding now that the Monark did NOT come with a D GS Pro, but maybe with a D GS motor. As you may know, Monark with the B motors used a Sachs standard part for the MX and a different GS part number for the parts for the GS and then only used a Monark parts number for the GS Pro. It's so confusing!

Donny Smith

[Bryson Williams]

Thank you Donny, I'm learning.  I just read something else that kinda strikes me as odd.  In the porting specs from Mark Holloways' Monark page I read that if you do the GS porting that you have to use a special GS Piston.  

 The article states that the rings are pinned differently then the stock Sachs. which I read to say won't hang up in the widened ports.  Any knowledge on this.  I'm wondering what exactly the difference is and where do you find the GS pistons. Will the mentioned GS piston work in a stock barrel.

Dirk Williams

[Bryson Williams]

Thank you Donny, I'm learning.  I just read something else that kinda strikes me as odd.  In the porting specs from Mark Holloways' Monark page I read that if you do the GS porting that you have to use a special GS Piston.  

 The article states that the rings are pinned differently then the stock Sachs. which I read to say won't hang up in the widened ports.  Any knowledge on this.  I'm wondering what exactly the difference is and where do you find the GS pistons. Will the mentioned GS piston work in a stock barrel.

Dirk Williams

[OUCWBOY]

Dirk,
The Monark GS piston part numbers are as follows:

54 mm = 0686 207 035
54.5  = 0686 207 036
55    = 0686 207 037
55.5  = 0686 207 038

The standard Monark pistons are
54 mm = 0686 207 025
and so on.

The GS had different part numbers for the head and cylinder as well. The GS Pro used different head and cylinder but had a special Monark (MCB) Part number.
Wish I had of paid more attention to this back in the day when I was working on these things.
Donny

Donny Smith

[firstturn]

Rob,
  Lets just say you are right about the Monark/D engine comment.  All I will say is when all the smoke clears there will be some Monarks turn up with D engines.  Now to further the problem I can't say what, when or how these engines ended up in Monarks, but as we all know manufactures always have something in the works and will use it in the case of needing to win or help (in this case) a factory stay alive.
  Just my thoughts and I have been wrong before, but at least WE air this history out for everyone to share and who is right or wrong isn't a issue with me.  Thanks Rob for you great input[^].

Ron Carbaugh

[Bryson Williams]

Thank you Donny.  Any idea where to get GS pistons, I have 10 or so Wisco Sachs pistons, I wonder if they are made both ways.  I'll have to dig them out and see.  

I do have one barrel that has been "worm ported, with the extra ports being right below the rings at the rear side of the barrel".  The barrel was semi-ported, however the port work is very sloppy and needs some finese, the piston is .60 over Wisco.

Dirk

[firstturn]

Dirk,
  On the subject of pistons all one has to do is be sure that rings wonn't hang up in the ports.  If you have a cylinder that has this problem and you can't find the proper piston all you have to do is reposition the pin that positions the ring(s).  A good machinist can handle this job or if you have a drill press you can do it yourself.
  The "worm ports" should have no bearing on the ring positioning because of its location.

Ron Carbaugh

[Bryson Williams]

Please explain the proceedure regarding the re-pinnng of the piston.  I'm capable of some things, however I have never done this or even thought about reloacting a piston ring-pin.

How does the existing pin come out.  How is the existing hole filled .  How does the pin stay in place after relocation, I'm assuming you use the same pin taken out of the origional ring-pin location.

Sorry to ask these questions.  My guess is that most of us haven't even thought about this kind of stuff before.  Please educate me/us.

Thank you.

Dirk Williams

[OUCWBOY]

Dirk,
Hopefully Ron will pipe in here soon. I have never done it myslef, but have heard of it being done before so that you could use Sachs cast piston in the aluminum and aluminum in the cast. Kip Kern told me about this awhile back.
I have not seen any GS pistons anywhere and don't know if that was the only difference between them. I wonder if there is any difference in the transfer port openings? But if there were, that could be easily corrected.

Donny Smith

[Bryson Williams]

The rest of the story is that I had Bill Cappel's GS Monark bored for him.  We purchase Sachs pistons from Alan B, and used one in the bike.

Went together no worries, Added a 32 Mikuni, an Internal Rotor PVL and the bike fired on the second kick.  Bill rode the bike about 10 minutes with nothing unusual happening. I'm sure the Barrel was a GS barrel as the porting was a work of art, and measured out proper for a GS. The only measurment that was questionable was the spigot? which was opened up, but not to 28 or 29mm.  

 Anyway I did not cut the intake side piston skirt to change the port timing, and was honestly unaware of two different style pistons. I'm guessing that lots of us are running GS ported bikes with stock pistons.  I want to get it right the first time, not after trashing Bike's.

I spoke with Allen B earlier today. He was also unclear on the two kinds of pistons.  If someone has both kinds of pistons "GS and Regular" could you measure the ring pin differences and share them with the rest of us un-informed guys.  


 Sorry to be a pain in the ass.

 Dirk

[firstturn]

Dirk,
  I am not sure there is a problem running the regular Sachs piston in a GS ported cylinder.  I have my own porting specs and have never used/measured the porting specs on a GS engine.  Unless the ports are elongated into where the ring pins are located there should be no problem.
  On to the pins.  Taking them out normally requires very strong and small needle nose to try and move it so it will come out.  Sometimes you get lucky(I am talking about all brands of pistons now) and the pin holes are in the inside of the piston where you can force the pins out from the inside out.  I have mostly used the same pin going back end except where piston manufactures (Honda) would send me new pins.  Just drill the new hole(position) undersize and gently force it in the new hole.
  Please don't everyone start trying this and ruin perfectly good pistons.  It is just a old trick we used in the past when we had to do so much R & D on our own.  OK OK[].

Ron Carbaugh