Pocketbike Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
158 Posts
Discussion Starter #1
Hi!
What mods are essential for the piston port engine?

I've read that you are only supposed to grind the bottom of the intake.
how much to grind away?
How much can I widen the exhaust port?
How much can I raise the exhaust port?
Are there any 2 piece cylinder/cylinderhead?
Or do I have to make my own?
Can't find any full circle cranks, maybe not available?

what about transfer, intake and exhaust durations?


What about reed conversion?
Is it worth convert it to reed intake?


I will post picture of my intake manifold. Cause it's different from the ones I've seen online.

Sincerely
 

·
Super Moderator
Joined
·
2,456 Posts
There is a vacuum port on the intake and if you grind into that vacuum port or do something that creates a leak it's finished.

The Piston skirt controls the intake Port like a valve adding reeds is not going to do anything except for impede the flow.

You can widen the exhaust Port about 2 mm on each side.

finding full circle cranks with the 10 mm pin is going to be difficult this late in the game since these parts are no longer manufactured a lot of people bought them for The Cagllari Daytona engine with the 40 mm bore.

They never made a two-piece head kit for the Piston ported engine there are some threads on how to do it here. I personally have never tried it.

The thing with the Piston ported engine is is there's not very many variables due to the sheer absolute simplicity of the engine. It has a very simple recipe for it to make power.

1. Boost bottle
2. Rocket key
3. Bass gasket delete
4. Widen transfer ports
5. Widen exhaust port
6. Lightning the flywheel with usual methods

If you install a full circle crank then you have to deal with balancing the engine.

Apparently from what I have read doing the head chop can be tricky to get the parts to seal and not leak compression and still have the proper squish to make power and not create detonation. Jim
 

Attachments

·
Registered
Joined
·
158 Posts
Discussion Starter #3
Alright.

I'm confused now cause my cylinder is different.
What i can measure it's a 43mm bore.

Intake use 4 screws.
159116
159117
 

·
Registered
Joined
·
158 Posts
Discussion Starter #9
This sucks.
I did not have plans to buy a new cylinder to this one.
And if I have to buy a new cylinder I also need a new intake cause the one I've got now got 4 screws and the TL43/TL52 cylinders has 2 screws.
 

·
Super Moderator
Joined
·
2,456 Posts

·
Registered
Joined
·
158 Posts
Discussion Starter #12
I think I just wet sandpaper the piston and use it as is.
Later i might buy the 44mm cylinder piston kit.
It probably will run with the piston and cylinder ive got.
The piston is in pretty bad shape though. But I think it work and if not I will have to buy s new cylinder kit.
 

·
Super Moderator
Joined
·
2,456 Posts
I just verified it is a 46cc EPA (Environmental Protection Agency in the US) scooter engine they have a weird 33.5 mm stroke as well I would do exactly the same thing try to smooth out that piston the best you can and then polish it with the dremel and polishing compound and swap the ring positions. give it a good port out and widen the exhaust port 1mm on each side replace the carburetor and just run it until it goes.

Then just keep your eye out for a 44 mm bore engine with a typical stroke.
 

·
Registered
Joined
·
158 Posts
Discussion Starter #14
Well i will buy a regular crank for it later and a 44mm cylinder kit and a intake manifold.
Cheaper than a new engine
 

·
Super Moderator
Joined
·
2,456 Posts
What I do is keep my eye out for used pocket bikes that have been left outside and are rusted and basically they're junk but the engine's still there I pick them up cheap for 20$ to $40 I keep the engine and any of the parts that are still somewhat good then throw the rest away.

I have also put up flyers at grocery stores with information that I want pocket bikes and will pay money you would be actually pretty surprised about how they start coming out of the woodwork once people find out that they can get a little bit of cash for that old pocketbike that's laying by the wood pile
 

·
Registered
Joined
·
158 Posts
Discussion Starter #16
In Sweden people thinks they worth their weight in gold unfortunately.
Even the Chinese ****.
So it takes time to find the right pocket bike with the right price
 
1 - 16 of 16 Posts
Top