swebass

Thanks for your kind words Martino! I had a lot of fun writing it. Haha, I was about to clean it, but then my dad walked by and said “young lad, you know that if you clean up the piston you might lose some compression”. So I laughed a bit to myself and left the carbon on top just to make him feel like he knew what he was talking about  😀

I…[Lees meer]

Also, the GPS measurements I used before was way off. It was an app in my phone. This time I have used a GPS for cars, so my speed measurents in this article are now correct. When I wrote before in my previous posts that I drove 54 km/h on a 105mm pulley I was wrong. It was actually 43 km/h with a real GPS. Sorry for that!

Hello again! Time has been short and I did work to many 12 hour shifts last week. Now I am done with my project. Please feel free to read about it here:

https://vespa-ciao.nl/forums/topic/the-50cc-road-racer-from-25km-h-to-65km-h-for-60e/#post-776130

Thanks a lot all you guys!

Guys, I absolutely don’t know why, but when I pressed Verzenden to publish this, something changed the word “gave” to “gift” and the word “of” to “or” in my text.

Thanks again Martino for great advice. And to the rest of you guys as well for being so helpfull! Now I have made a plan from all your input, from Graham Bell and from other great posts on this forum. I will give it a go next week and regardless of how it turns out, I will write an article about it in the project section when I am done.

Cheers guys!

AA-T,  This was the answer I was looking for! Thank you for spending so much effort on the answer. I was also thinking that raising the cylinder and milling a bit of the top might be the better option in this case. I am going to measure how many mm’s the piston is covering the bottom of the exhaust port and then raise the cylinder accordingly…[Lees meer]

I read Graham Bell again and realised I misunderstood the concept of a offset sparkplug totally, so forget what I said about that. But these two quote kinda confuces me a bit, especially the last part:

“Reducing the squish clearance is not easy, you can’t just machine 1mm, or
whatever, off the head as the compression ratio would end up many…[Lees meer]

Also, where did you get those thick base gaskets? Did you craft them yourself or did you bought them somewhere?

Martino, thanks again for good answers!

That at least give hope when it comes to sanding down the cylinder head since I will not get my hands on a mill any time soon. Tho I read in the Graham Bell book that it is not adviced to mill the cylinderhead if your spark plug is not centered in the cylinder top, and my sparkplug is offset to the center.…[Lees meer]

Martino, thank you for writing such infornative answers. I wish I had a mill to use to mill down the cylinder head and the cylinder top. But sadly I don’t.

• I know there are ways to flatten the cylinder top using sandpaper on a flat surface, but I do not know if that is adviced at all?
• For doing the ports, did you use a drill, a dremel and…

[Lees meer]

Ritze, Thanks for your input. You are right in that sense, one would need a lot of knowledge to get things right. I have allready planned to read a book or two on two stroke tuning, and Graham Bell is definitly on my to-read-list.

Zevenenergie, thanks a lot for the link! Now I do not need to buy it from Amazon.

Martino, My guess is that Sweden in general is a bit more pricey. I have been in Holland at least 15 times, and prices of every day items like food is at least 30-40% cheaper than in Sweden. Anyhow.

Thank you for your detailt post! It gives me the urge to start experimenting. I have some questions if you feel like you want to help me out.

• What…

[Lees meer]

Ritze, I looked in your post as you adviced. Thanks for the inspiration. I think I am sort of understanding what you did with the cylinder. You are probably right about practicing on a separate cylinder then the one I ride on currently.

Is 37€ a good deal for a complete cylinder kit, second hand in a top notch condition? In that case I might h…[Lees meer]

KillerNoway, thanks for the headsup. I bought nozzles from 60-72 to play around with, as soon as my package show up. Even tho I find the 66 to be giving good performance atm. I have no off sounds or weak spots in the acceleration. It just goes straight up to top speed and sounds perfect, with a good draw over the whole rpm registry. Colour of the…[Lees meer]

Ritze, thank you for interesting input. I am indeed interested in modifying the stock cylinder. Do you have any pictures or any documentation on how you created those 4 ports? Maybe there is any good forum thread you could recomend? When you say 1,5 mm wider and higher, what do you mean by higher? Do you mean grinding some extra towards the top…[Lees meer]

Martino, good point, I totally forgot about that!

AA-T. I measured with a GPS. 50km/h in slight uphill, 60km/h in steep downhill, and 54km/h on flat ground. I also did measure the old school way by distance and time, and got almost the same results.

My goal is just to have a smoother ride. ATM it is kinda fun to ride on small roads just because…[Lees meer]

Thanks AA-T! I think I get what you are saying. And I will indeed try a smaller pulley. The reason I was curious about the rpm was because the link Martino gave me about how to calculate the top speed (in theory at least).

So used the formula backwards to calculate my rpm, which should be around 8300 rpm if I drive at 55km/h with my setup. This…[Lees meer]

according to this:

Dynojet uitlaat test mei 2018

Cilinder: 38.2 mm met gevlakte kop
Carters: Snor
Carburateur: 12/10 met sproeier 45
Filter: Snor

a Gianelli Original Power would give 7140 rpm. But that setup is a bit weaker then mine. Hmm.. Any educated guess about my current maximum rpm?

The rpm/acceleration is indeed very high. I will try a 80mm pulley then. About speed, the only thing I am not sure about is the rpm with this current setup. The cylinder is getting a lot of fuel air mixture for being only 50cc.

A pulley and a matching belt are not expensive things, so I guess I could just buy them and try it out!

Thank you Martino!