Question about reeds
 

Hey guys. I just bought an old 1986 RM250 to play around on. I finally got it running yesterday but it has very little power and wont idle. Ive already cleaned the carbs, changed the plug, and it has fresh gas but im not sure if its the right mix ratio (im running 20:1 now but i think it may be a little rich). THe air filter is new too. Some one told me that the reeds could be bad. I pulled them out and some of them are sticking up about 2 mm which i think is way to high. Is this too high? Could new reeds help the power and idle problems? I dont know much about reeds so any info would be apprectiated

If the reeds aren't closed completely when relaxed it'll never run properly, although at higher revs it may not be so noticeable.

There shouldn't be any tension holding them closed, they should be completely straight and flat, no creases or visible damage at all. If you've got any doubt about them, replace them, and don't try to bend them at all, the consequences of breaking one can be horrible, and beware those who tell you you can open the stop blades a bit - it rarely helps anyway, it's normally the reed block which is the restriction - if you do you must ensure that the curve is carefully arranged so as to ensure the reed takes a nice easy bend.

Are they the standard steel reeds? I think you can still get the resin two-stage Boyesen reeds, on certain bikes I remember they improved the low end torque usefully.

thanks for the info squid. Theyre not steel. I think they are fiberglass maybe but im not sure..... I ordered just some standard stock replacement ones. I hope they help i cant wait to get back in the dirt!

Just curious, what are you talking about? Reeds??? :?

Thanks :D

If you are serious????? He is talking 2 smoke (oops stroke) motors.

Okay, so what are 'reeds' when your talking about 2-strokes?

Have a look here

Fantastic, thank you very much :D I'm now 'in the know' :)

That's a good, simple explanation of what reeds are, but it suggests that using reeds allows 'bigger' ports, this is not absolutely accurate.
A piston ported two stroke has to have quite conservative port timing so that the primary compression does not cause significant levels of blowback, this restricts the inlet duration and limits volumetric efficiency, particularly at low revs.
Using reed valves in the inlet tract allows more radical port timing, so to say that the ports will be bigger might be true, but it's more to do with their positioning.

I thought they were tuning a saxophone :)