Simple Reed Valve

[Tyler6357]

@Taylor6357...You really need a windowed piston to take full advantage of a Reed.

My suggestion since you really should replace a piston and cylinder together is just get a cylinder with the 40mm spacing and have a host of much better upgrades available to you.

The zeda80 cylinder is a 47mm bore cylinder so it will work on your motor and the windowed pistons offered come in both the high and low pin versions so that's not an issue.

Again, I don't work for nor am i some secret sales person for zeda motorsports but they offer some nice stuff at very good prices.

Call the number on the site on the home page and leave a message...he will call you back then talk to him...he can do any porting work needed and honestly I'm not sure what port work your friend did but there really isn't too many correct ways to port a 2 stroke cylinder.

You already have alot of other great bolt ons mainly with the head and exhaust..now it's time to put them to good use.

He has the cylinder, the oz Reed and a piston combo deal...ask him to port the cylinder for you...tell him you have a pk80 and I'm sure he will send the correct piston

Order one of the .6" copper head gaskets and then head over to eBay and you can find the mikuni vm18 carb for just under $80.00

Or you can add some torque and throttle response with the small Reed kit and be happy with that.

You basically have $200 plus vs 30 for the small Reed...plus a windowed piston and rings..$25...a stock cylinder $25... Cylinder base gasket and head gasket $10...so really the good stuff isn't that much more...Maybe 125 or slightly more but the difference in power I'm sure would put a big smile on your face.

I agree with you, I should get them together. Why not just get a 40mm spaced cylinder? MZ Miami sells them for only $17. Cheap enough for me to screw it up and have to get another one, ha! They also sell the type "B" window pistons for $15. It makes sense because then I will have many more options for a 4 or 6. My friend certainly knows how to port these things, he has alot of experience and having a mill makes it come out perfect and nice, it's just that he is a very busy man, if you know what I mean. Anyhow, I will check out that ZEDA place, they do have higher quality and good prices too. It's cool that the guy will work with you and even port it for you. MZ has ported 40mm spaced cylinders for $45 (see links below).

Also, I always have a smile on my face when I ride this bike, haha. To be honest, I don't really want to go much faster on this thing, it is a bicycle after all and I gotta keep reminding myself of that. The pipe already wakes it up but some more low and mid range torque would be nice. I also got a nice double walled fat rim and a disc brake but my suspension fork doesn't have a disc brake mount so I'm looking for a different fork. I'm sure I can find decent used one around here.
https://www.ebay.com/itm/MOTORIZED-...ood-Quality-/272176885781?hash=item3f5f01b015
https://www.ebay.com/itm/MOTORIZED-...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649
https://www.ebay.com/itm/MOTORIZED-...NTAKE-SPACE-/282408034298?hash=item41c0d49ffa

 

[6blueoval9]

To gain more low-end and midrange to compliment the 0z Reed, the cylinder needs porting in manner to do just that...from what I can see on the mz head the ports on the cylinder side are widened which is a good thing sort of..they went fairly wide which is more aimed at top end air flow volume than making bottom end torque with air speed...The ports are matched but to which gaskets used I couldn't say...Hopefully you can find out and get those specific gaskets.

In any case the mz cylinder will still most likely need some work done to the intake side to match up and blend to the Reed.

Let us know how it turns out...I'll be doing a Reed build once I finish up my current motor build...check it out if you like...just search "pure stock zeda80 build"...I can't get any copied links from this site to work for some reason.

 

[FurryOnTheInside]

To be honest, I don't really want to go much faster on this thing, it is a bicycle after all and I gotta keep reminding myself of that. The pipe already wakes it up but some more low and mid range torque would be nice

I have not done "one change at a time and test" but followed advice from others on the forum, and lengthened the intake tract to 7-7.5" (I went 7.5") measured from the face of the carb slide to face of the piston. This is supposed to be a good mod for the low-to-mid range torque, and is supposed to work with a reed valve too.

 

[Tyler6357]

I have not done "one change at a time and test" but followed advice from others on the forum, and lengthened the intake tract to 7-7.5" (I went 7.5") measured from the face of the carb slide to face of the piston. This is supposed to be a good mod for the low-to-mid range torque, and is supposed to work with a reed valve too.

Hmmmm, never heard of that, I will try it without the reed valve. I'm using a kinda short 15mm billet intake, I'll see if I can get a good measurement, I might have to pull the carb back toward the seat tube to make it longer.

I'm still thinking about the reed valve. Understand that I'm still breaking my engine in, I've been running a kinda rich jet for the first 2 gallons but today I moved from a 66 jet to a 65 and the 4 stroking stopped at the top end and I got a lot more low end too, it seemed like a dramatic difference for just one jet size but the 65 is definitely the right jet as it's set up right now. Maybe this small 2 petal one would make enough of a difference for what I was looking for. Hmmmm, wish I could try before I buy, haha.

 

[Tyler6357]

Wait, 7 inches?

 

[FurryOnTheInside]

Wait, 7 inches?

Sorry, I'm slow to reply.. watching horror movies.

Yes 7" to 7.5" according to two different sources, measured all the way from the forward face of the slide to the rearward face of the piston. The intake manifold tube whatsit wouldn't be 7" to 7.5" long.

Ideal length of intake

• FurryOnTheInside
• Sep 11, 2017

If the ideal intake length from slide to piston is 7-7.5", then I have to offset the carb to...

Quite a few people are using the extended intake tract for low RPM torque benefits.

I don't know what specific quantity of benefit I got from it because I am not doing the scientific method. I did a whole bunch of popular torque, reliability and stealth mods at once before even starting the engine, and I'm still in the break-in stage too.

Intake arrangement

• FurryOnTheInside
• Sep 11, 2017

"final" intake made from 45° bend fibre reinforced silicone hose and two chopped intake...

(Others already did the hard work pioneering and scientifically testing, and have published their experiences, so I am just following the popular modification routes to reach my intended destination. )
I'm only mentioning that the extended intake tract mod exists, so you can search and read the info and detailed studies yourself and do your own testing if you wish.

 

[Tyler6357]

I see, thanks for posting pictures, that helps. How much do you think you can you pick up extra on that set up? I mean, a lot or a little? A noticeable amount?

 

[FurryOnTheInside]

I see, thanks for posting pictures, that helps. How much do you think you can you pick up extra on that set up? I mean, a lot or a little? A noticeable amount?

I never tried it with the short or stock intake. It's my first build. I wanted to get it built and get riding, so I just trusted in the research done by better mechanics and took a leap of faith.

I think it was @jaguar who said. 7.5" and either @butre or @StreetRyderz who gave the figure as 7" , I'm not sure now.

I expect that I lost some top speed but gained acceleration and hill climbing, which suits me.

Jaguar's site:
http://www.dragonfly75.com/motorbike/

 

[6blueoval9]

Hmmmm, never heard of that, I will try it without the reed valve. I'm using a kinda short 15mm billet intake, I'll see if I can get a good measurement, I might have to pull the carb back toward the seat tube to make it longer.

I'm still thinking about the reed valve. Understand that I'm still breaking my engine in, I've been running a kinda rich jet for the first 2 gallons but today I moved from a 66 jet to a 65 and the 4 stroking stopped at the top end and I got a lot more low end too, it seemed like a dramatic difference for just one jet size but the 65 is definitely the right jet as it's set up right now. Maybe this small 2 petal one would make enough of a difference for what I was looking for. Hmmmm, wish I could try before I buy, haha.

Reeds work, even small ones....I was looking at reeds today and noticed the smaller kits use a rather small inlet tube...one I saw was 13.5mm which is essentially what a stock NT carburetor measures out to.

With you having a 15mm carburetor I would consider boring the Reed inlet tube to at least 15mm to take advantage of things.

One thing I don't recall seeing is what rear sprocket you were using?

A sprocket change alone can further multiply the low end torque you already have.

 

[Tyler6357]

Reeds work, even small ones....I was looking at reeds today and noticed the smaller kits use a rather small inlet tube...one I saw was 13.5mm which is essentially what a stock NT carburetor measures out to.

With you having a 15mm carburetor I would consider boring the Reed inlet tube to at least 15mm to take advantage of things.

One thing I don't recall seeing is what rear sprocket you were using?

A sprocket change alone can further multiply the low end torque you already have.

That makes sense. When I first starting building this bike I was thinking of upgrading it with a shift kit in the future so I put a derailleur on so that if I wanted to put the shift kit on it would be pretty easy and would only need a jack shaft and an extended peddle crank and I would be ready to go. Until that time I could go with a direct drive set up and I got a clam shell adapter. I had to shop around to find one that had a smaller diameter to fit my 7 speed cassette hub. I found one but I'm not real happy about it. It's got a 9 bolt set up and just isn't that good. It's difficult to get the sprocket straight and to spin without a slight wobble. This is the one I got--> http://www.livefastmotors.com/produ...e-motor-clamshell-sprocket-adapter-small.html I'm using a 40 tooth sprocket and a high quality BMX chain. Do you know of a better sprocket adapter I can use?