400 restoration project

[husskifan]

THANKS BARRIE THIS IS VERY HELPFUL SO FAR

[Go Go Diablo]

Barrie - those are good points explaining about how to maintain the position of the ignition plate. When I work on those Hirth motors, I mark the position of the plate by using a sharp chisel and laying it across the seam between the plate and the housing, a slight hit with a hammer stamps a nice clean alignment line.

I also always replace spark plug wires and plug caps. I have found 7mm spark plug wire with a metal core (not a carbon core) work very well and the caps I use snap on to the spark plug without removing the barreled cap on the plug.

The Hirth motors have a mechanical advance on the inside of the flywheel. A spring loaded mechanism that turns the cam slightly with centrifugal force. Do the JLOs have that too?

[snocatpete]

Good morning Barrie and Bruce. Just reading your posts and Bruce I agree with you on the chisel trick. I too use a very sharp small chisel aligning both parts very precisely. But this seems to me that this is just a good reference point if you know that is the right location for the timing plate. Eg. if the engine was running prior to taking it apart and assuming that the plate was in the right location to begin with. But what if you receive an engine all in pieces and where someone has removed the stator plate without marking it? How would one know where the right spot is where it should be tightened down? Have either of you guys come across this problem and used the procedure in the book to figure out the right timing location? Have you set timing using the procedure recommended by the engine manufacturer using the dial indicator and a multimeter to set the timing? Also I agree with you Bruce on the spark plug wire. I don't fool around taking the old one out, I simply cut it off and remove it from the fan wheel housing and then install a new one on reassembly. I also use a coper core wire and I buy them in a set of 4 and the part no I use is standard #403W then I cut them to length. Also when installing it in the coil, I use a caliper to measure the depth of the coil then I transcribe that onto the end of my sparkplug wire with a pen and as you know, the spark plug wire is screwed into the coil, not pushed in. My pen mark on the wire is my reference to know that I am completely seated in the coil. But prior to installing the coil wire I install a dust boot on the end of the wire from an old spark plug so once it is in I can slide it down over the coil making a good seal between the wire and coil. This particular jlo engine does not use a mechanical advance. Its basically set it and forget it.
Coming back to timing, timing is as you know is pretty important. Too far advance makes it hard starting and rough running engine and so on. Too far retarded and you aren't getting a good burn and you are low on power.
I have also noticed some talk about points and condensers on the forum lately. I go by the rule of thumb that if you are changing points you change the condenser as these two work hand in hand. I recently overhauled an engine and the points were completely burnt black which is a tell tale sign that the condenser is not doing its job. The way I change the condenser is that I unsolder the wires (obviously) and then I have a special tool to support the stator plate and then I drive the old condenser out using a large punch or old socket approx. the same diameter. To install the new one I clean the body of the condenser with scotchbrite and then if you look carefully on the stator plate at the condenser you will see 3 indentations so what I do is slightly file them out using a round file then I clean the inside of the base plate where the condenser goes, super clean, then you should be able to push the condenser in with your finger then I get it to where it should be located then I take a punch and I reswage those three indentations ( ever so slightly) just enough to lock the condenser in place. the reason those pieces should be super clean is because the condenser has to make a ground to the body of the stator plate. I think I read some where that someone had hammered on the condenser - huge no no. It is a very light duty piece of tin. I think I will stop here seems like I am blabbing on and on now. Really enjoy following along on your rebuild Barrie, it is going to be a nice machine when you are done.

[Go Go Diablo]

Some very good points too Pete, Seems I'm still learning little tricks on the forum here. Like the comment about scribing the plug wire and the dust boot. Good stuff there.

The Hirth motors are a bit different in regard to condenser installations and yes, I have reset the timing and there is a procedure for this I should explain some day. But this is a good Hus Ski post and I'll save those comments for another day.

Keep on my friends!

[Barrie2777]

Although dust and dirt is a common enemy to electrical stuff, if the plug wire is seated in the bottom of the coil connection it will probably have a dust proof seal. I think the bottom of the coil "hole" is tapered therefore making a tighter fit the more the wire goes in.

[snocatpete]

Totally agree with you Barrie. The chances of moisture or dirt getting behind the flywheel and down onto the coil are slim to none but when I have it apart, I put that dust boot on it just as extra piece of mind plus I think that dust boot being so tight on coil and the wire it also helps to eliminate any vibrations that can occur from a single cylinder engine so less wear on the coil wire and the screw insuring a nice contact between them.
I am including some photos of the dust boot part that I use

[snocatpete]

I also mentioned about changing the condenser and then filing it down and installing and reswaging it. And also cleaning the body to make sure it had a good ground.
After stating that, I thought I should do some research to back this up. So the photo with the literature explaining how to do this is from a Bosch book. The second photo is taken out of a Hus ski service manual and I posted this photo which really shows the 4 ground connections on the stator plate
I am also adding this picture showing the construction of a condenser just for fun....
anyway, I am going to stop talking/posting now as it feels as though I am taking over the 444 restoration topic here!

[Barrie2777]

With that pesky stator plate out of the way, you can unbolt the crankcase bolts which holds the two crankcase halves together. Two long bolts at the top, four short ones elsewhere.

[Barrie2777]

I have skipped a couple steps. You can see in the photo that the cylinder head is removed and the cylinder is still in place. This is because this particular engine that I am rebuilding came to me like this. What you cant see is that the piston and cylinder has seen so much water that the two are practically welded together so I have to dismantle this engine with all those parts attached together. Normally you would remove the five nuts holding the cylinder head in place and pull it off. Then remove the four nuts which hold the cylinder to the engine base and lift it off.

[Barrie2777]

The studs which hold the cylinder to the base protrude about 1-1/4" . Fortunately for me, this engine seized with the piston at almost the bottom of its stroke. I was able to force the rusted bearing to rotate enough to lift the cylinder above the studs. With this accomplished, I could then separate the base.