I'll never, never modify an engine again. I'll never, never modify an engine again. I'll never, never modify an engine again. I'll never, never modify an engine again. I'll never, never modify an engine again.
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As you all know, my D's original top end has disappeared into the west coast dark hole and I don't think I'll ever see it again. Sigh!
However, there is good news: I really wanted to fit a nicasil kit and they weren't available when I sent my top end to the "place that dare not say its name." Now they are available again, and, hopefully improved as exhaust spigots used to break off the first ones.
They come sans head and I wanted a squish type head rather than the bathtub chamber stock to the Ds. So I picked up a 125 head from a DL and set to modifying it. I didn't really want to modify it myself but the oil field is firing back up again and all the shops are no longer interested in time consuming novelty work.
So I used the d head gasket as a guide and filed the head's cylinder stud holes oblong to suit. This meant that the combustion chamber had to be offset for best stud placement. Next I made up a head holding fixture for the lathe. This allowed me to machine the combustion chamber to suit the revised stud spacing -- tricky, as the head mating surface has to be held absolutely square. That done, I then had to machine flat the area surrounding the stud holes for the cylinder head washers. Something that would take minutes on a milling machine, took quite a bit longer with a drill press and a dremel.
The oblong stud holes mean that the head can "wiggle" a bit: not good for the precision required for an effective squish band. So the next step is to install dowels to the cylinder so the head is held exactly in position. The head gasket should make this a simple operation.
My last trifling problem is that the 125 DL head is thicker than the stock 150D head. Yup, the cylinder studs are too short: by just a smidgen, of course. I have longer studs on order but I think they will also be thicker which means I'll have to line bore the cylinder's stud holes!
All this to say, I am waiting, yet again, for parts!
PS: I also am cleverly using a Li crank and piston as they are much stronger and better built. However, this means I also need piston shims to center the rod properly. Yup, I am waiting for more parts, again.
PPS: I'll have to mount the exhaust, when I find one -- I have several leads but nothing solid yet -- very securely to make sure the cylinder's exhaust flange stays put.
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I'll never, never modify an engine again. I'll never, never modify an engine again. I'll never, never modify an engine again. I'll never, never modify an engine again. I'll never, never modify an engine again.
Repeat after me...
Moderator: Moderators
...and all of this could have been avoided IF someone that works somewhere which will never get a dime from me again would have just done as promised and shipped YOUR part after charging you for the work...what he has done is criminal.
�Long live vintage motorcycles that are too tough to die...�
- Dustin Kott-
- Dustin Kott-