Crankcase ignition wire rubber grommet pops out

[kawacarl]

I have a "73 125 Six Days 6 speed that the rubber grommet that holds the wires coming through the crankcase from the Motoplat will"pop" out after being ridden for a while with a loud "poof". The grommet is not in very good shape but I can't figure out what is causing this. This is a Doug Wilford built engine that has less than 300 miles on it. It just started doing this when I rode at Hodaka Days last year. Any ideas anyone? Could the ignition side seal be bad?

Carl

Carl Mendenhall

[Larry Perkins]

Carl, might get more response on this in the general discussion section as opposed to wanted/for sale.

[Dale Fisher]

It sounds like you have a good watertight wire/grommet setup, that is until the "poof".  Logic would say pressure is building from somewhere.  The most logical/only source is the crank seal.

Dale Fisher
Penton Owners Group - President/Memberships
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[454MRW]

KTM engines have a vent hose on top of the cover that runs up underneath the tank to vent, both to help keep moisture from forming inside the cover, and release pressure that is built up from heat expansion. You very well could have a seal leaking, but I would recommend venting the cover anyway. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico

[Paul Danik]

Carl,

   Does the engine run properly and idle down as it should? When you take the side cover off is there any oily residue in the bottom of it? Does slowly turning the air adjustment screw in and out have an effect on the engine speed at idle?

   If the seal is indeed bad, it can be replaced without splitting the cases. Also, be sure to use a brand new seal, not a "NOS" item. While the seal is out try check the condition of the crank where the seal lip will ride, if it is rough possibly some cleaning up of the area would be prudent.

   If the engine is running perfectly, and if slowly turning the air adjustment screw in and out has an effect on the engine speed at idle, and if there is no visual evidence of the seal leaking, you may consider putting in a new grommet and see what happens.

Hope this helps.
Paul

[454MRW]

Do these tests Paul suggested with the ignition cover off, as a sealed cover will nullify your test results. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico

[kawacarl]

My mistake for the wrong section

quote:Originally posted by Larry Perkins

Carl, might get more response on this in the general discussion section as opposed to wanted/for sale.

Carl Mendenhall

[kawacarl]

Thanks Paul, I will try these suggestions and post the results

quote:Originally posted by Paul Danik

Carl,

   Does the engine run properly and idle down as it should? When you take the side cover off is there any oily residue in the bottom of it? Does slowly turning the air adjustment screw in and out have an effect on the engine speed at idle?

   If the seal is indeed bad, it can be replaced without splitting the cases. Also, be sure to use a brand new seal, not a "NOS" item. While the seal is out try check the condition of the crank where the seal lip will ride, if it is rough possibly some cleaning up of the area would be prudent.

   If the engine is running perfectly, and if slowly turning the air adjustment screw in and out has an effect on the engine speed at idle, and if there is no visual evidence of the seal leaking, you may consider putting in a new grommet and see what happens.

Hope this helps.
Paul

Carl Mendenhall

[kawacarl]

Thanks for the response.

Carl

[kawacarl]

Paul,

The engine idles down like it should, the air screw affects the idle speed. When I got into it I found the Motoplat base plate was loose.Two screw were backed out about 3/16" and the other was just
loose. There is NO oil around the seal. There is some metal dust that I cleaned out, so I do not see a need to replace the seal.
Since both the base plate and rotor have slots to allow rotation, I assume I should get the base plate to get a rough timing adjustment then fine tune it with the rotor adjustment. Is there a better way?
I have a 5/64 drill bit that fits the aligning holes perfectly!

Carl

Carl Mendenhall

[Paul Danik]

Carl,

   It sounds like you have the timing sequence figured out. If at some point once you have the timing set you ever need to remove the base plate, before doing so you might consider taking a sharp chisel and use it to create a reference point on both the engine case and the base plate where they meet that will allow you to quickly and accurately re-align the baseplate during reassembly. A scribed line would also do the job, but I always just took a chisel and with a little tap created a mark that was easy to realign even in not so great of conditions if need be.

   In all the years of being involved with Sachs engines I don't recall ever hearing of your situation. I would think it would take a bit of pressure to pop that grommet. My gut feeling is that you might consider getting a new seal and having it and the needed tools in your tool box just in case you find the seal is the culprit while many miles from home at an event. Please keep us abreast of any new information on the "poofing grommet".

   If anyone else has any thoughts for Carl please chime in.

Hope this helps,
Paul

[Richard Colahan]

I'm a bit confused here...but then again I'm far from a Sachs/Penton expert...
However, I have dealt with timing external rotor Motoplats on various Huskys for decades.
When you say that the "rotor has slots to allow for it to be rotated", I'd have to ask: Are you sure? Every Motoplat (and Femsa) rotor I've ever worked with has a single key-way that fits over a woodruff key in the tapered end of the crankshaft. It's position is fixed on the crank.
The timing is set by rotating the base plate only. On external rotor systems a small pin is inserted through the rotor "timing hole" to match a similar hole in the base plate. Timing is correct when these 2 line up at a designated piston position btdc measured either with a degree wheel or a dial indicator (example: 2.0 mm btdc).

Can someone clarify for me the rotor adjustment for fine tuning?
Does the Sachs engine NOT have a key-way fixed position rotor?
Always something new to learn, even for us old guys!![?]!
 

quote:Originally posted by kawacarl

Paul,

The engine idles down like it should, the air screw affects the idle speed. When I got into it I found the Motoplat base plate was loose.Two screw were backed out about 3/16" and the other was just
loose. There is NO oil around the seal. There is some metal dust that I cleaned out, so I do not see a need to replace the seal.
Since both the base plate and rotor have slots to allow rotation, I assume I should get the base plate to get a rough timing adjustment then fine tune it with the rotor adjustment. Is there a better way?
I have a 5/64 drill bit that fits the aligning holes perfectly!

Carl

Carl Mendenhall

Richard Colahan
1969 V1225
Upper Black Eddy PA

[Paul Danik]

Richard,

  You are correct, the rotor / flywheel is keyed to the crank. I re-read the post and see that the terminology is incorrect and you recognized that fact and I did not. When Carl used the term rotor he should have said stator, I read what he wrote and envisioned what I thought he meant...  My wife gets mad when I do that with her..

   The base plate attaches to the Sachs engine case and it is slotted and the slots are fairly long. The Motoplat stator then attaches to the base plate, and it is also slotted, but not nearly to the extent of the base plate.

   It is possible to attach the base plate in a position where you can not get the timing set properly by just turning the stator with in the range of its slots. If that occurs the base plate would need rotated to allow for the timing to be "dialed in" using the slots in the stator.

On the Sachs you have to remove the stator to get to the screws on the base plate, as the stator pretty much blocks access to those screws.
That is why I always create an alignment mark on the base plate and the case to allow for a simpler reassembly as I know I can "dial in" the timing using the stator slots if my base plate is aligned with my chiseled slot on it and the case.


Paul

[kawacarl]

Richard,

By rotor I meant the stator. It has the word rotor imbedded in it. It has the three screws to hold it to the base plate and it is also movable along with the base plate.  Sorry that I used the wrong term.

Carl

Carl Mendenhall

[kawacarl]

Paul,

I am using a plunger tool screwed into the sparkplug hole to find the TDC of the piston to get the proper 3.2mm BFTDC timing. To get the 3.2mm, I have to have the base plate adjusted to the extreme CCW movement. Also the stator has to be adjusted to the end of its CCW slots to get the 3.2mm. I always question when an adjustment is put to one extreme or another. Am I missing something?

Carl