Reedvalve - any suggestions for a smallblock?

[a.j]

I have the large one on my 225 cast, with the fins cut to suit. Never had any issues. Pulls well & gives pretty good economy.

[wrecklessrobbie]

Hi
Sorry to crash the thread. Will a 25mm dellorto fit onto the small atomic reed valve? I bought a 25 mm dellorto. I am thinking of trying it on an AF 200 kit for small block hopefully with a reed valve. Can the asso pistol supplied be used or do I need to buy another piston?

Robbie

[corrado]

Hi
Will a 25mm dellorto fit onto the small atomic reed valve? I bought a 25 mm dellorto. I am thinking of trying it on an AF 200 kit for small block hopefully with a reed valve. Can the asso pistol supplied be used or do I need to buy another piston?

Robbie

No you'll need one of these rubbers to fit that carb. http://www.lambrettaspares.com/spares/i ... b0817.html
Speak to AF about the piston, they told me that it wasn't necessary to cut windows in the piston but a half moon shape cut into the piston skirt was required.
RB20 piston should work too but you'll need a TV rodded crank with it.

[yozzer]

I'm fitting an lth reed valve to my rt225 running a 28mm carb, does anyone have any suggestions on how to drill the window in piston ?

[rosscla]

Put the top end on without the inlet manifold. Put the piston at bdc, mark where the inlet is on the piston, makes couple of holes. Look at a couple of TS Pistons and you'll soon get the idea


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[tavspeed]

running a mb one on my jb tuned race rapido 225,pwk 28mm carb,saigon scooter taffy exhaust,pulls like a train on sx200 gearing 16 tooth front,couple of issues,the carb bottom sits or touches the cylinder cowl,had to remove the small spigot from carb bottom and put a a indent in the cowl,on tick over the carb shakes like mad on the rubber mount,causing petrol to overflow out of the outlet,ran one of the smallbore tubes off the outlet up high past the carb,
goes like s**t off a stick,but does about 35mpg,hardly any spitback,so where all the petrol is going fook knows.

[alanscottj]

Hi guys, I am still making a decision on fitting a reed valve and am seriously considering the Atomic Mini. The thing I am still unsure about is concerning the piston. I understand that my Mugello piston will need modifying, my question is, do you have to cut the piston windows AND cut the piston skirt? Or is it one or the other? The reason that I ask is that AF Rayspeed can cut the piston skirt for me for only £15 so I am thinking of getting them to do it for me.

Any thoughts most appreciated as always

[coaster]

It's one or the other, not both. However, you will loose top end performance if you don't use a piston with windows as the reed valve obstructs the airflow. The way to get the performance back is to go for 360 degree inlet timing which means that the piston will need windows. If you can live with losing the top end then cutting the skirt instead becomes an option. Personally I'd buy a reed valve piston and be done with

[jason frost]

Here's a Asso/Vertex piston

[Andy W]

I have just fitted a small atomic reed block from Corado on to my cast 200 barrel, i have opened the inlet port in height both up and down cut a boost port and cut a window in the piston (Mahle thin ring) and a cut away in the skirt. hope to have it fitted this weekend and see how it goes. I cut the window by working out where the piston sat in the port and then carefully holding in a vice and drilled 3 holes with a 13 mm drill and then cleaned the slot/hole up, again seeing where the skirt sat in the port cut/filed a 5mm deep slot in the skirt. Now when turning the engine over there is a point when both the window and skirt mod are in view giving 360 inlet. Niether are too big but just enough to allow the open inlet.

Engine will be running a 28mm PHBH that has an adjustable power jet fitted (closed at moment), and will probably end up with my Fran Race pipe for now as I've just sold mt Taffy copy. May end up fitting a NK road pipe or the TSR EVO touring pipe.

Andy