BMW R7 Motorcycle Engine

[dsquire]

German

This is a beautiful engine that you have so carefully constructed. I am sure that it will be a good runner for you when you have it broken in and fine tuned. Thanks for providing the many photos of your progress as you built this fine engine. It was my pleasure to watch this engine come to life. :bow: :bow:

Cheers *beer*

Don

 

[Lakc]

Good going! :bow:

 

[gbravo]

Thank for your inspirit mails, now I am seeing the exit of tunnel.
In this moment (when I have free time) I am working in repair some few oil leakage in the timing case, adjusting the external covers, finding the best ignition configuration for locate the coils in his place (under the upper engine cover) and obviously tuning the engine.
German

 

[Groomengineering]

Very nice work German! Thm:

Cheers

Jeff

 

[dgjessing]

It's a beauty! I can only hope to someday do an IC engine (let alone such a nice one) .

 

[gbravo]

You only need propose you and work with enthusiasm and lot of patience.
This is my first engine and I am so satisfied with this proyect, that I am working in design my next engine.

 

[gbravo]

When I built the engine for the first time I connected the two spark plugs in parallel with a single coil and as I explained in some previous messages, this system does not work due to the difference in conductivity within compressed combustion chamber and the chamber with lost spark. Then when I got a second coil, I fabricated a new bracket to place both coils at the top of the engine, trying to start the engine with this configuration I was not successful and noticed that the spark plugs had both a lower intensity, so remove coils from that position and put them out of the engine, starting immediately the engine, as seen in the video shown last week.

Now, I try to reassemble the two coils over the engine but be noticed that with the two coils together, exist interference between the magnetic fields, affecting the intensity of the spark. To try to solve this problem, both coils was rotated 90 degrees in order to place both in parallel but had no success, even tried to place a non-magnetic metal plate between the two coils, increasing the electrical isolate in both coils, etc, but none worked.

Finally, although I had some fear of the electrical insulation, I connected a coil over the engine with the plugs in serial, finally achieving an excellent result with the engine running very well with the coil in his place. For this connection, I increase the isolation in all wires from the hall sensor and the primary coil.

I've done several tests with this configuration with very good results, even I have reviewed the effect of electrical noise generated by this configuration, without noticing any interference. I have therefore decided to keep this setting.

German

 

[gbritnell]

Hi German,
It looks like a nice compact installation. So to go over what you are using. It's an S&S ignition with the coil and circuit board separated. The coil is then tapped off of the other ground connection for the second plug. Your Hall wires go to the circuit board which you have mounted remotely. Is that about right?
gbritnell

 

[gbravo]

George,
Yes, is an S&S CDI with separate coil (actually, originally had the coil attached, but I removed it and cut the diagonal ground link, anyway are equal).

The coil was rotated by 90 degrees from the first position so that the primary terminals are at the rear and secondary terminals to the front.

From the CDI card three wires go to the Hall sensor and two wires to the coil. For the wires to the hall sensor I used an old mouse wire, in which I removed the outer cover, leaving the screen to view. This cable, together with a common two leads wire, was introduced in a heat shrink tubing in order to form a single electrical cord with the hall sensor signal electrically isolated from the signal to the coil. This is the wire that you see in the lower right corner of the last photo. Arriving at the rear of the coil, both wires to the primary leave the cord and the shielded continue inside heat shrink tubing to the right side of the coil and connect to the Hall sensor with Futaba connector.

From the secondary each terminal is connected directly to each spark plug.

I also like this solution because it is very clean and compact.

Regards,
German

 

[Admiral_dk]

Your final solution is VERY similar to a full size bike of yesterday and the R7 model range are from yesterday (my youth) - I love it !

I'm very impressed and even more by the fact that this is your first :bow:

 

[Lakc]

Finally, although I had some fear of the electrical insulation, I connected a coil over the engine with the plugs in serial, finally achieving an excellent result with the engine running very well with the coil in his place. For this connection, I increase the isolation in all wires from the hall sensor and the primary coil.

Thats the way to do it! Those systems are hard on hall sensors anyway, so there is no guarantee they will last forever, but as long as the plug wires dont fall off or ground out any failure wont be because of the serial plug connection.

 

[gbravo]

I covered all wires with Nomex (special insulator paper used in high tension transformers and electrical engines) and over this I apply heat shrink tubing.

 

[Lakc]

Thats fine, its about all you can do. I think some of the hall sensor failures occur at board level, not necessarily the wiring. From what I can tell, the commercial and diy designs seem to lack a bunch of components that contribute to circuit "robustness".

 

[gbravo]

OK, I will cross my fingers

 

[gbravo]

Gentelmans,
Finally my engine is finish,

This is the original BMW R100 with R7 engine

and my engine,

From upper left side,

And front view

German

 

[gbravo]

More pictures,

German

 

[gbravo]

And the engine running ....

[ame]http://www.youtube.com/watch?v=2ByWEupWAZU[/ame]

 

[ShedBoy]

Great runner well done :bow: :bow:
Brock

 

[metalmad]

That is just gorgeous!!
Pete

 

[steamer]

That is just gorgeous!!
Pete

Isn't it! :bow: :bow:

Dave