Z750 Twin Forum

I think the head is stock height - ie no machining. I will check it against another I have. I want to arrive with a CR of around 9:1.

Yes, I see what you mean about the plug entry. 

On ALL of my headwork I have always radiused the hole were the threads break through into the combustion chamber. The main reason is it reduces the possibility of a hot spot. I also carefully index the plugs, that is probably taking things to extreme - but it was something I learned from a master head work guy in the 1960's and I have always done since then !

My pal with the garage workshop space is calling to see me tomorrow - I hope it is good news for the move. After all the health and other problems from the last 2 years, I really want to start the main build.

It is possible that KK and myself will convert some extra heads to twin plug. I will need another one for the 40DCOE Weber engine.

Final chassis part arrived today ..........................

Michael, what are your latest thoughts on ignition ? There will be 2 engines - the original Weber version and the "Glemseck" supercharged version.

My pal has 2 hospital appointments next week - after that we start moving my project into his garage / workshop.

Hi TJ,

I have got my Sachse ignition box repaired, after discussion at half price.
Haven't tested it yet.
Hope it will do it's job this time.
The seller states I have used a wrong ignition coil !?!
Well ...
It includes 9 preset, but selectable ignition curves and a rev limiter at 7.000 or 7.800 rpm.
https://elektronik-sachse.de/shopsystem ... -twin.html
Some members of the Z750Twin community are using it without any issues.

My other favourite is Ignitech from Czech Republic.
http://www.ignitech.cz/en/vyrobky.htm
Full programmable box, cheap, but the "mechanical" part of timing sensor is not included and needs to be done by ourselves.
There is an instruction how to do that, but I prefer a complete "bolt on" set for that.

Hope this helps.

Best regards,
Michael

As ever Michael I thank you for your input. 

I will check both sources. 

I have decided NOT to go with the 860 conversion, as it's not really necessary with a blower ! I can spend that money on ignition and other parts that I need.

Is there a link for what your twin plug head man used for his ignition ?

Hi TJ,

Martin did the twin spark plug conversion.
As far as I know he uses a stock ignition out of a LTD model (CDI).
That is pointless and virtually maintenance free, but needs swap of the rotor and minor changes to the cabling (CDI box needs more cables than point ignition).
It doesn't have a rev limiter !

Cheers, Michael

Some progress now [ Michael !!! ]. The ramp is now installed in my Pal's garage and the chassis, wheels etc will be round there next week. The plan is to get the rolling chassis assembled as soon as possible as he is away in the US for 3 months next Spring. While he is away I will be working on the 2 engines in my shed - my original [ 1976 ] with the 40DCOE Weber conversion and high level exhaust - and the Glemseck blown engine in the spare frame. That will be making up blower mounts, manifolds and also the blower drive. I also have to make patterns for the under frame fuel cell. Imagine the style of a Moto GP belly fairing - that will be my fuel tank ! The Manx Norton 5 gallon "tank" is actually a dummy - just a cover. Underneath will go all the electronics and timers etc as well as the Nitrous Oxide solenoids / pumps.

Hi TJ,

that is good progress !
Now get the parts over there and grab a key to the garage for the months he is away, that will give you freedom to install the engines and have a test run on his premises

I am heading forward to restore two B-Twins in more or less stock condition during this winter.
Two or three engines are on the workbench as well.
My Racing-Twin needs some updates too, but it is on a good way.

My son Nils wants to race next year for the first time with a bike on a racetrack.
He has experience with Karts on racetracks and he is a very good bike rider, even he is only 19 years young.
He is enthusiastic and skilled
I am going to buy a BMW F650 single, grab the engine, carbs, ignition, high level downpipes and some other parts and dump the rest at ebay.
The engine has to go into an Aprilia AF1 (125cm³) aluminium frame with single sided swingarm and USD-fork.
Will be an ultra-leight-weight racer at approx 140 kg and 48 HP
Any chance for me and my Twin at approx 190 kg and 50+ HP ?
I'm afraid no

Ok, hope to meet and see you, sprint-racing at Glemseck 101 in 2018 !
Don't forget to ask for reservation if you want to attend the sprints

All the best,
Cheers, Michael

Michael, unfortunately I will not be able to use the garage while my pal is away. He has a very complicated security system. 

However, I will not waste my time - I can work on the 2 engines in my shed.

The F650 is a power unit I have been looking at with interest  for some years ........... ah well, let me get one project finished first !

Hi TJ,

I / we had no big choice in regards to that engine.
It has to be slim and the Aprilia AF1 has the drive chain right(!) hand side and the rear swing arm is mounted through the engine case.
It's stock 125cm³ engine is a Rotax as well, hope the F650 engine will fit in there or can be modified to match that setup.

I am looking forward to see you finishing your Twin projects and meet you at Glemseck 2018 !

Cheers, Michael