Yogi's take on a Duclos Gearless

[yogi]

Thanks guys 

Zephyrin, very interesting. Do you have a build thread I missed somewhere?

Thanks Dave, I will be on the forum, while I'm gone, but obviously nothing out of my shop to contribute.

[Kim]

Congratulations on the first run there Yogi!  It's looking great!
Best of luck while your away for work.
Kim

[Zephyrin]

Yes Yogi, I've send some pictures on the built here,
http://www.usinages.com/threads/un-moteur-4-temps-sans-arbre-a-cames.82383/
I hesitate to duplicate all this stuff on an other forum, I will simply post on MEM in a short while my finished engine in a new thread since I dont want to occupy your thread further.
I add that you did the good option in increasing the size of the engine;  most of the setbacks and difficulties I had in setting up the ratchet wheel movement come from the tiny size of my engine...
How did you find the correct valve spring stiffness ?

[yogi]

Thanks Kim 

Zephyrin, I'm looking forward to read more about your engine, it's a very interesting build. (I don't know how many MEM members are frequenting your forum, but for myself, I can say: "Je ne pas parle francais") 
As for the valve springs, I just went to my spring stash and found two springs that seemed right. The exhaust spring is not critical, but needs to be stiffer than the intake spring. The intake spring needs to be light enough to open atmospheric. It seemed to work OK on the short test run. I will tune the engine once everything is finished, and the intake spring might need some attention. So, to answer your question: I just went by feel. The intake spring is the lightest spring I had in that size.
I'm glad I enlarged the engine. The fiddly bits are fiddly enough even in the enlarged version... 

[vcutajar]

Congratulations Yogi for a good runner.

Vince

[Zephyrin]

I just went by feel.

by feel, good to see that in a thread full of high level of technics and skill a place is left for that!
it was the first time that I set an atmospheric intake valve, hence the question, and it seemed to me odd, no advance, no overlap and yes, really soft spring !

[yogi]

After being away for a while, I finally made it back to the shop again. 

The work on the engine continues with some governor parts.

The governor weight arms are next.
First, I machined the finished contour. Milling a bit deeper than the thickness of the finished part, to allow for the second side to be finished later.






Unfortunately I didn't have fitting brass stock and ended up wasting a lot of material when I machined the back side off. I have some brass on order, but I just couldn't wait to get back to making parts again. Anyway, not the end of the world, even though I really hate wasting material! 




After cutting the two pieces free, I finished the second side to the final thickness.




The last operation was to cut a round mounting boss, where the wights will be mounted on.
I clamped the square part very gently in a round collet.  That's not ideal, but as long as none of the edges end up in the slots of the collet, and the collet doesn't get cranked down to hard, it works alright. A square collet would be preferred here, but unfortunately, I don't have one.






The finished parts:




I also turned the governor spood:




And the parts together:

[rudydubya]

Nice, precise work, Yogi.  Still following along.

Regards,
Rudy

[zeeprogrammer]

Good looking parts!

The finishes in those first couple of shots are impressive.

[Doc]

Very nice looking usually when I end up with thicker material then I need I mill the profile a little deeper then band saw or slitting saw parts off. I just hate making brass into chips must be the frugal in us! Anyway nice work!

[b.lindsey]

Good to see you back yogi. Lovely looking governor parts too!

Bill

[Dave Otto]

Very nice Yogi!

Its good to see you back in the shop.

Dave

[yogi]

Thanks for the compliments guys! 
Doc, I hear you. Turning all that brass into chips was painful... 

[yogi]

I have a couple more pieces for the governor made.

The wights have a recess to fit around the hub of the flywheel.
The first operation was to mill the recess with the same radius as the hub on the mill.




Then, I moved over to the lathe and finished it to size and parted it off.




Last, drilled and tapped the holes for the set screws. This will also provide a mounting location for springs.




The finished weights:




Next, I made the bracket with the pivot for the arms.

I started on the lathe, turning a ring.






Using the trusty soft jaws, the ring is chucked up in the vise for milling. Have I mentioned, I love my soft jaws? 




Unfortunately, I forgot to take a picture when I milled the slots for the arms. Sorry guys! 

And the finished bracket:




As you can see, the work continues, even tough is feels to me like it's just creeping along, as we get closer to the end.

Yogi

[yogi]

The last part for the governor is the latch.

I milled it out of a brass bar, that was just about the right thickness. It only needed a light surface cut to bring down to the correct dimension. To hold the work, I used CA glue to stick the brass to a piece of aluminum, which I then clamped in the vise. The contour is milled using light cuts, to not put on too much load on the bond. It worked very well, and I think I could have done a bit deeper cuts, as the glue held really well, but I just didn't want to take any chances. After I was done, a bit of heat to release the glue and separate the parts.








The governor finished assembled. There are probably some adjustments and tuning needed, but we'll have to do that with the engine running, so we'll get to that later.








Next, I'll be working on a fuel tank/vapor carb.

yogi