making non-reedvalve a reedvale

chuck russo va /

i just picked up a 93 sprint and i thought the ignition system was shot but after i played with it i got a nice fat spark,

it has a A5 bottom end and a a3 top end they did this to sprints in 92 and 93 and i was wondering if i got a a5 top end and manifold would it work on it?

Re: making non-reedvalve a reedvale

Hey Chuck, I think that was about the time they were changing the engines over to A35, if so, I think they were sorta rare. Call Chris at Mopedwarehouse, I think he has one. But I thought it was the other way around.. A3 trannie and A5 Head (?) Doug D. (VA)

Re: making non-reedvalve a reedvale

Reeperette /


Either top end works on either engine, so long as you match the intake manifold up right, and can get a piston with the right friggin size pin/bushing combo.

Tho for preference, try to use the A5(A35) Piston with that head, cause the holes in it seemingly act as another port, which would probably increase performance some, but an A3 piston will work in a pinch.

Lemme know if you run into any problems with that, ok ?


bushings and carbs

I remembered something... I believe he DID give you the right bushing... but then that bushing is supposed to PRESS into the connecting rod with a lot of force... (no fit loosely like it did)... THEN... the ID is supposed to be reamed out to the proper ID.

This is all a process that has to be done right by people with precision tools and proper equipment.

So... that rod is just plain shot.

Also... I'm not all that sure that the carb from the reed valve motor is set up the same as the one without the reed... so that may have played a part in why it wouldn't run.

100psi oc compression should let it run... it may not run strong... but it should have run.

Might be that flywheel keyway/pin too.

Re: bushings and carbs

Yeah, that bushing should have to be pressed in there. Puch had a special hand tool to do that with on their cranks. Puch Repair Manual Diagram NO. 6740 on Page 48.

Fred, your always right, you moped Gawd ;)

Ree... how is the bike coming?

Re: bushings and carbs

Reeperette /

>>Also... I'm not all that sure that the carb from the reed valve motor is set up the same as the one without the reed... so that may have played a part in why it wouldn't run.<<

Yeah, I checked that....they're the same, only difference at all seems to be the intake manifold you put on them.

As for the rod, if these are the kind where I can swap the rod arm or whatever that widget is, imma take the good one I have and do that, with the right size piston, whenever Ike gets around to reading his Email, that is.

As for the flywheel and keypin, the cursed keypins are way too small stock, and in truth do not fit up right, they're too short, and the fit is loose, even brand new - so it shouldn't be impossible to have one's probably "hardened" tho, so I have to ask some folks that supply odds and bits to the "Big Three" what can be found or made along those lines.

But yeah, the DelLorto 14/12 carb that comes with em is identical in every aspect save for the intake manifold attached to it.

I've looked into this a bit, and they did make some A3 type heads (the hexagon shaped ones) that used a reed valve, but you would no doubt have to buy an offset intake manifold to fit the carb up.

The intake mounts just off to the left (your left if yer behind the 'ped, mind) on the A3 cylinder, but is dead-on straight on the A5(A35) head, so be aware of that, cause for the A3 you need the offset intake, and for the A5(A35), just the straight one - AND make sure to check whether or not you need the oil injector screwhole, cause they make em both ways.

And, umm...try to deal with a parts guy who isn't going to tell you "There's no such thing!" like they did with me, tellin me no A3 piston ever had a 12mm wristpin - it saves a lot of hassle when you don't have to convince the parts guy that said part exists at all in the first place.



Reeperette /

The A3 Reed Valve cylinder is a straight manifold, not an offset, having looked at one myself.


Re: Correction.

chuck russo va /

well i just sent out money for a 99 lx motor and im gonna use the top end off it to make the sprint reedvalve and i might move the electronics on it so i can make it have a offset manifold so the carb has easier access

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