50cc case reed conversion

[DanTerzepter]

Hi all,

For a while now I have been working on making the 50cc motors go quick, I have had mine up to 63kph on flat ground before snapping the frame. Since then I have put the engine on a new frame and I am shooting for 70+, I recently got a vm18 carb and did a light port job on the cylinder. I'm sure this will get me there with the other mods I've previously done, but I was wondering if i would be able to convert the 50cc engine to case reed. I'm sure doing this would be a first and would definitely be unique.

all I'm waiting on before I get the bike running is a new reed valve that'll fit on the 32mm spacing due to my 32mm to 40mm adapter developing a leak and I wanted to take it out the equation.

 

[JerboaJohn]

very involved project! other than cutting the case yourself and somehow mounting the reed block, you might be farther ahead to get a 38mm stroke case reed lower end and adapt the 40mm cylinder to it. there's not enough interest in the small HT engines for anyone to have case reed production for them.

are you set on using the HT 50? other engines like pitbike and scooter 2 strokes have a bigger fan base and more parts for them,,
here's a good read - this guy has done a lot of experimenting with HT engines - http://www.dragonfly75.com/motorbike/perfect48cc.html

 

[DanTerzepter]

there's not enough interest in the small HT engines for anyone to have case reed production for them.

That's my whole reason for wanting to try this, no one has done it, I like the challenge of making the HT 50cc engine decently quick. It's more to see what this engine can do.

I have also read through that website and seen what he has done.

 

[LewieBike]

You'ld probably have better luck with adapting a different cylinder jug from a known saw like a Husky or Stihl.


There's very little meat in the case of these engines and machining in a window for a reed without the proper thickness and integrity you'll just make a mess of a CG engine.

https://www.ebay.com/i/122731076561?chn=ps

I'm not saying this has already been done, but it stands to reason it would be an easier job for a DIY conversion. Frankly I like these old school engines as they are. They run well when set up correctly, and pull OK over a wide RPM range. Going to a homemade intake without a lot of previous 2 stroke experience will be frustrating and may waste a lot time and effort.

 

[Spare_Parts]

I'm sure it's been done. It's easy enough. This is a 66.

 

[DanTerzepter]

You'ld probably have better luck with adapting a different cylinder jug from a known saw like a Husky or Stihl.

The main problem with doing this would be making sure the rod lengths, or the stroke is similar or the same between the two engines otherwise the piston might go too high in the cyl and hit the head, or it might go too low.

 

[Street Ryderz]

The 48-50cc are great little performer's,have a better balance and can make serious power when done right.The case diamentions are the same below the cylinder base,doing the case reed is being done alot atm and the 48-50cc would be exactly the same build.I have an actual 50cc engine from Grubee's old starfire line and it's a rare varient now but was done like no other I've seen yet,there are pics and details on this forum about it.Most are 48cc and have the potentail to out run most so called modified 66-69cc engines,they can rev up quicker and can hold higher rpm.I've gone 47mph or 76kph on the 50cc as a p/p and my son went just over 80kph or 50mph on it with a modded potatoe pipe,we have yet to put an actual pipe on it LOL.

 

[Spare_Parts]

I'm sure it's been done. It's easy enough. This is a 66.


View attachment 85529

Forgot to mention that is not my engine or picture lol

 

[Sumsloppymeet]

i was debating on doing this to the Aosom 60cc ive got sitting on my dresser thats never been ran yet its just hard to find parts for it so i dunno what i wanna do with it yet

 

[Street Ryderz]

i was debating on doing this to the Aosom 60cc ive got sitting on my dresser thats never been ran yet its just hard to find parts for it so i dunno what i wanna do with it yet

That's the thing with the more rare varients it's next to impossible to find the parts now! That's the only reason I'm not running the 50cc currently,I need to seperate the crank and replace the big end bearing just to be safe since there is alot of hard miles on it.Then Im going to bite the bullet and have the jug replated (nikisil) while it's still doable,and the hard part is I need another domed piston since all the late model ones are all flat top and this engine used the squish with it's rechambered stock head and there really isn't any after market one for them.When this 50cc's casting are compared to the current models well you can see there is alot more meat and much better quality.