review of Rock Solid reed valve

[Deleted member 12676]

Just got it in. Here is my technical review:

Design flaw
Sucking on the intake side of it reveals an air leak. Took it apart (3mm allen wrench) to discover the internal gasket covers only half of two 1/16" diameter holes that bypass the reeds. not good. (see drawing)
So all owners need to take it apart and glue those holes shut with something gasoline resistant like JBWeld. (silicone sealant wont work). It will run much better sealed. And trust me, there is no reason to have bypass holes. The reeds need to completely prevent all blowback.

Flow Volume
Looks like the maximum possible flow volume (cross sectional area with both reeds open) should be 111 square millimeters which matches the 113sqr mm of a 12mm carb. But since they didn't angle the valve downward it then hits the upper port surface after only opening 2mm which results in only 84 sqr mm volume.

Performance
This is going on my 55cc engine with 12mm Dellorto carb ported out to 14mm. If I bore the intake to give the upper reed more room to flex then I expect to be able to rev even higher since this ported engine is limited by my homemade reed valve which has stiff reeds and only around 88 sqr mm flow area. But the crankcase on mine is stuffed which makes it favor high rpm power. I am making an expansion chamber for a peak rpm of 9300. See my web site (click on my signature link) for info on how to drill holes in the pistons intake skirt and make a boost port. These are essential steps for use with a reed valve. I expect this valve will give low rpm gains for both 48cc and 66cc engines but will limit revs on the thirsty 66cc engine.

My recommendation to Rock Solid:
Seal those holes to begin with. And design a wider reed valve to be sold with 66cc ported cylinders that allow a wider design. And angle the valve downward. (And make the mounting hole spacing 40.5mm for the 55cc and 66cc engines.)

 

[Fabian]

Recently bought a RSE reed valve kit, installed it once but was too lazy to re-jet carb

Ok, so let me get this straight - you bought one of the best items you can fit on your bicycle engine and you then choose not to spend approx $2.00 on a larger sized jet, which is a "requirement" for proper operation when installing the reed valve intake.

Does this not seem like a completely foolish idea?

 

[BadgerMW]

I was thinking about it at first, but after buying a high comp head from fred, Jags CDI, the reed valve and a SBP exp chamber and shift kit i was getting real tight on my budget. I had a 15mm dellorto sha clone that i haven't used yet, will try to port the piston and see what results that brings with the dellorto clone.

I originally tried it on a stock engine from BGF, and it revved up like crazy for a couple seconds before it would shut-off automatically. I have a new motor with all the parts listed above that Im still putting together...been impossible to find a free weekend. Will let u know how it goes once I get it all together. After talking to Jag it made me want to give it a try.

 

[BadgerMW]

The reed valve was more of an impulse buy then anything, went on a buying spree that day haha. From the site it looked like a bolt and go part but once I saw it wasn't I just put it the side to get to it later....With my crazy schedule (Full time job 55+hrs a week, going to school in evening, and a gf that wants my attention lol) its hard to find time to experiment.

I wouldn't call it foolish, impulsive yes but not foolish.

 

[BadgerMW]

last post: I have a BGF and Skyhawk GT5 motor, with the parts i listed above which motor would be the best to go with or from your opinion are they basically the same?

 

[Fabian]

@ BadgerMW

I was in a similar situation and my solution was to promptly get rid of my girlfriend when she started demanding that her time in the relationship was more valuable than my time messing around with a motorized bicycle - her ultimatum: it's either me or the motorized bicycle.

I still have my motorized bicycle; and loving it!!!

 

[Bikeboy]

You can buy a tip cleaner for a might welder it is tiny round files in incremental sizes that can be used to make a jet a bigger size, I have jetted several bikes this way, I usually order small and file up to what u need if I don't know the correct size to buy.

 

[Jonj57]

Sorry to ressurect this thread but I have a question, you said the reeds only open up by 2mm topside, so I ask would it be worth it to grind away a small indent in the top of the port where the reed touches to allow it to open fully? (Obviously smoothing it down within reason) I understand that a smooth intake tract is important for good flow, but wouldn't have the almost 20% or more additional flow easily offset any turbulence created by the indent? Also would the indent actually affect anything realistically? I figure you're making the indent just above the reed tip so the fuel/air would be almost entirely past the bump right as it comes out the reed right? I have spare cylinders I might try dinking around with this idea if it doesn't sound to stupid to you guys.

 

[Steve Best]

Yes, it is worthwhile and I have done it with larger engines.
Here is a stock Yamaha Blaster intake port and reed box:

Here is the epoxy mod I did to (area in red is built up with epoxy):

Here is an actual picture of a filled reedbox compared to stock:

If you open the reeds up too far, you will overstress them and have them break.
How far is too far? Try it and find out. If the reed is the bottleneck, there are gains to be had.

The goals are:
1) reduce reedbox volume (cross section area constant).
2) open reed onto a smoothly curved surface
3) smooth airflow off the reed
4) open reed to the same area as the port.

 

[Street Ryderz]

If a reed set up is what you want this would be the best way to do it IMO! zeda is doing some very interesting stuff lately you can buy just the sleaved jug with piston for $135 or the sleaved jug and dio reed sys complete for $225 and that is a deal !

 

[Jonj57]

If a reed set up is what you want this would be the best way to do it IMO! zeda is doing some very interesting stuff lately you can buy just the sleaved jug with piston for $135 or the sleaved jug and dio reed sys complete for $225 and that is a deal !

That quite the deal, where can I find that? Eitherway I'm stuck with what I have and wont spend more money to get slight gains, I prefer to modify what I have til its broken or overused.