r/2Strokes

1995 rm80 piston and cylinder

Hey fellas, so longer story short I recently got my cylinder punched for a new piston and got it together (hastily), bike ran like crap, did a comp test and only had 90psi from what I think is a warped head. Total engine time was 15min or so. But when I cracked the cylinder open I also noticed a pretty glazed bridge path and some glazed port zones. Nothing catches a nail thank god.

But I was trying to haul ass and get this bike running I think that I didn’t clean the cylinder good enough or chamfer the ports enough and some grit found its way into the rings there.

I have three questions

1. Are these rings toast?

2. I have already bought a bottom end gasket/ seal kit and plan on cleaning the bottom end , is this overkill or ?

3. Any advice on how to prep this top end so I don’t fug it up so bad this time ?

Thanks gents also please go easy on me, first time 2 stroke building.

Ok so I have this 2008 derbi senda and I noticed this weird branch section from the main pipe.

My questions are: What is that? Does it help with anything? Should I remove it and weld something to cover the hole?

And yes the exhaust is off because I had to work a little bit on it.

Looks like its running almost perfect but expect the unexpected soo in open to any tips or advice. If It looks a bit wet in the photo its because i cleaned It with some brake cleaner but its was completely dry when i pulled It out

Hello, I need information about rotary valves. I don't know anything about that system, but I need to know a few things for a project, so i need your help.

- Are the ducts in the covers for lubrication?

- If they are for lubrication, are they lubricated with the mixture or with oil?

- Does the oil or mixture that passes through the ducts end up in the sump during intake?

(I wrote this using Google Translate)

Bought a new exhaust for my Derbi. Seller explicitly wrote that it would fit my model, but it doesn’t. How could i in theory make this fit?

Hey there, does anyone got a few ideas to optimize my Supermoto 50cc?

Are there any ancient wisdom & time honored tricks necessitated by a lack of funds, forcing the hand of ingenuity to make something outta nothing that would allow the 2 stroke to achieve more gains? I am very strong in the financial part of it & lacking in the other department. Anything anyone would part to me would be very greatly appreciated. Thank you. Its a 1984 Honda Aero 125cc 2 stroke w/ keinhin PB 18mm carb.

Hey, just put together a new top end. And i cant remember if this noise is normal? Crank has no up and down play