Hi guys

[OllysSpeedShop]

Recently built a Honda ZB50 clone and the Chinese engines are junk so I purchased a very used Honda C50E engine. Once I removed the stuck piston with the help of a sledge hammer I stripped it down, replaced the crankshaft with a 12v one to run a lightened flywheel and converted the stator to full wave. Replaced all the JIS hardware with caphead hex.

Unfortunately the head was ruined so I replaced it with a generic e22 head with miniscule valves compared to the C50 one, was actually quite surprised to see such huge valves on a small standard engine.

In case you're wondering why a 50 and not a 90, I'm limited to a moped licence for now.

[PeterT]

Well Olly, your off to a flying start Welcome

[loadedtoad]

With regard to the licensing are you sure it's classed as a moped in the UK.
Capitano on this Forum has done some thorough and up to date research on the subject and from memory the C50E engine you are building is not classed as a moped engine.
I personally don't mind what you do regarding this stuff.
I put YB100 engines into a FS1Es and 400cc barrels onto RD250s, Honda 400T engines into the the 250 version back when we could ride them on L plates.
We knew we where taking the P*ss but didn't care back then because the plod had no chance of finding out or even catching us
Nowadays it's a lot different just don't want you to innocently get caught out.

[OllysSpeedShop]

With regard to the licensing are you sure it's classed as a moped in the UK.

I appreciate your concern. I go by the pre 2013 definition of a moped which allows me a whole 31mph vs the new 28mph standard.

When I build an engine I tune it for low down torque and usually run 2 stroke cdi to retard the timing near the top end. Then I experiment with the gearing and a GPS Speedo until it will no longer pull me over 30.

In my youth I discovered ooracings restrictable CDI units which were switch activated. Limiting to 30 for road use and then derestricting for those "private test track" moments. These days I'm happy with 30, I just like to get there as quick as possible.

[Capitano]

With regard to the licensing are you sure it's classed as a moped in the UK.

I appreciate your concern. I go by the pre 2013 definition of a moped which allows me a whole 31mph vs the new 28mph standard.

The moped licensing post is here:

viewtopic.php?f=43&t=35951

Also some useful information on Cubs and their classification.

viewtopic.php?f=43&t=35969

If your Z50B clone was registered as a moped between 1977 and 2013, and carries the required plate stating that it is a moped, and you have category P on your licence, you'll be OK ... unless the DVLA decide that the engine change moves it into the category of a light motorcycle.

If it's a sub- 50cc engine restricted to 30 mph, technically it should stay as a category P moped. If you were ever tempted to try and question the DVLA about it, my advice would be simply, "don't!"

[OllysSpeedShop]

I find asking the DVLA anything is a huge mistake. Anyway, as it happens the new engine has exactly the same engine number as the standard one, how lucky is that?