I 've made a cheap and easy extension to the Rooteq trolley which I expect will fit my BF20 Honda short shaft (not tested yet). You do not need soldierings with this. The trolley stays almost same foldable after the changes.
I used the following parts.
For extending the horizontal bar:
1 square iron tube 2.5x2.5cm 11cm length (to fit it into the main vertical bar).
1 square iron tube 2x2cm 22cm length (to fix both the horizontal tube and the 11 cm tube).
You get an extra 10 cm length which I expect will be enough for the BF20 backwards balance weight.
For extending the T-shaped support:
2 square iron tubes 3x3cm 10cm length .
You will get and extra 10 cm width which will help with stability when servicing the engine.
All tubes are 2mm iron thick.
You must remove the plastic stoppers from the horizontal tube and T-shaped support tube.
You have to use a file to iron out the tube borders and bolt holes in tubes. And maybe some hammering to get the tubes inside.
Of course it's also a good idea to use some bolts and nuts to make it stronger. But be careful with the T-shape extensions: if the trolley rests on the bolts, your work is useless. It must rest on the plain surface tube.
Maybe some paint to protect the tubes. If possible, paint as much as you can (also inside tubes), but beware that painted tubes may not fit (I wish I could have get zinc galvanized tubes such as the Rooteq trolley has).
I wish Rooteq could sell some materials to extend the trolley ease and safely. It's not so complicated. I think that any 15hp-20hp 4-stroke may benefit from this. Otherwise engine portability is a joke.
As soon as tested I will post (I need some friend to help me, I'd rather not load the engine alone on my own).
Anyways I wish I had come across another cart before. You can get this one in Amazon and Discount Ramps.
Here is a photo with dimensions: