Reed perfomance and powerband

[ratrod]

Hi All, i have a 66cc superrat and i am looking for more perfomance in the form of a powerband if its possible???
Does anybody know if we are able to make a reed valve set up on these 2 stroke engines. As far as i know they run them on the 2 stroke motocross bikes between the inlet manifold and the engine block. do anyone sell them or have been sucessful in making a similar product?

 

[ratrod]

Heres some info from rock solid

Good morning John,

The Chinese crank cases where never designed to incorporate a reed valve set up, and thus it will not give you the benefits of adapting one to it, we have designed reed valves for them to be mounted at the intake manifold, but all our Dyno tests have shown no considerable increases in torque or power over the given rpm range.

You would be better to modify your engine in other ways to try and increase the power output, or alternatively we are releasing a 10HP water cooled 2 stroke engine kit which incorporates a reed valve to the crankcase, very scary when the power comes on tap with this engine.

Cheers


Tony Riccio

Rock Solid Bicycle Engines
AUSTRALIA

Warehouse 5
Lot 11 Beor Street
CRAIGLIE QLD 4877

 

[GearNut]

If you want a powerband, get yourself an SBP expansion pipe.

 

[ratrod]

Hi there Gearnut I have one already and was so impressed by the improvements that i was just wondering if it was possible to bring a powerband in like the yz cr rm kx trail bikes on a smaller scale.
Tony from rock solid was very helpful, he has run tests and that was the info i was after. i wont worry about persuing this with this engine although i may look at the aluminium performance head next.

cheers john

 

[GearNut]

Besides having a tuned expansion chamber, modern two strokes such as those you referenced to also have a power valve which essentially alters the exhaust port size depending on the engine's RPM's. (Reed valve is a given here). The power valve broadens the power curve to enable a more friendly power delivery instead of a sudden, short lived power burst at a certain RPM. That would be really tricky to work into a cheap HT engine.

Here's a pretty good read on them. It's short and to the point:
Dan's Motorcycle "Power Valves"

 

[ratrod]

GearNut your a ledgend!!!!this infomation is great i didnt know the extent the power valve played in powerband and the read was interesting.....cheers for that, on my next project i may look at this again that 10hp watercooled motor may be a good contender for a beginer like me... the Roach is the other end of the scale and is just one mean bike with big balls required to ride fast...

thanks again top read !!

 

[Rocksolidperson]

GearNut your a ledgend!!!!this infomation is great i didnt know the extent the power valve played in powerband and the read was interesting.....cheers for that, on my next project i may look at this again that 10hp watercooled motor may be a good contender for a beginer like me... the Roach is the other end of the scale and is just one mean bike with big balls required to ride fast...

thanks again top read !!

Rock solid have now actually realesed a reed valve kit for there engines http://www.youtube.com/watch?v=tR4dqSf16xE

looks like they have done some revising on the reeds, this is my build and in my opinion they increase pulling power from 1/4 throttle to about 3/4 then i come on the sbp chamber zooming to 60km/hr it definatly gives more touque in midrange power.

 

[ivan H]

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According to Jennings research adding reeds to a motor of this type yields power increase of approx 20 percent without other mods. Much greater increases are possible by porting the piston so it breathes thru 180 degrees instead of 60. A smaller carb must be used due to lower intake velocity. A boost port can be cut from intake port to the height of the transfers, with a port also cut into the piston to feed the boost port. I have just recieved rocksolid pullstart ' will now order reeds from them. Cheers

 

[Drewd]

So far the only thing my RSE reedvalve intake does is prevent fuel mixture from contaminating my intake. I have not noticed any change in power changes (top speed or ability to climb hills faster or acceleration) with my newest build. My gearing, jetting, and tuned pipe are all set for hill climbing

 

[ivan H]

I havent gained any top with RSE reeds, but have better lo/mid torque. Using 11 tooth of the jackshaft, stock chainrings & shimano hyperglide I was using 6th gear as top. Now I can use 7th gear. I have just cut 2 ports in a piston, both 17mm high, 9mm wide & left a 6mm section seperating them (intake port has previously been widened by 3mm). I'll start on the cylinder tomorrow, lower the intake port & add a boost port. Cheers

 

[crmachineman]

Alright Ivan! Nice job with the experimentation! I've been doing a lot myself, and learning a lot! Even though my intake plenum I'm using also improves low and mid range engine performance, I'm curious too see how it compares with using a reed valve assembly.



-Fred

 

[ivan H]

Hi Crmachineman, Thanks. I also removed 5mm x 24mm from the skirt bottom. I had hoped 2 do the cylinder (lower port floor inner edge & cut boost port) last weekend but time didnt allow. The reason 4 adding reeds is to allow the piston porting, so the motor utilizes much greater intake duration. It'll b good 2 c wot gains result. Cheers

 

[crmachineman]

Yeah, I agree. Just the fact that you can do that extra port makes it really worth while.

-Fred

 

[ivan H]

Yeah, aside from the small size intake & exhaust ports, these have very limited transfer capacity. It is possible 2 add 2 more transfers surface cut into the cylinder wall behind the transfers & 2 the same height, taking care 2 keep them in front of the ring ends, tho I dont know if it'd b worthwhile without reeds & ported piston. Cheers

 

[bigbutterbean]

Heres some info from rock solid

Good morning John,

The Chinese crank cases where never designed to incorporate a reed valve set up, and thus it will not give you the benefits of adapting one to it, we have designed reed valves for them to be mounted at the intake manifold, but all our Dyno tests have shown no considerable increases in torque or power over the given rpm range.

You would be better to modify your engine in other ways to try and increase the power output, or alternatively we are releasing a 10HP water cooled 2 stroke engine kit which incorporates a reed valve to the crankcase, very scary when the power comes on tap with this engine.

Cheers

tt
Tony Riccio

Rock Solid Bicycle Engines
AUSTRALIA

Warehouse 5
Lot 11 Beor Street
CRAIGLIE QLD 4877

This was over a year ago, so where is this 10hp kit?