Jawa cylinder reed conversion

Ok so I got this cylinder to play with and found out it had this big stupid plug. After welding a nut to it and slide-hammering it out eventually after some persuasion, it left this big old nasty cavern. Thought, well maybe some kind of lil reed setup will fill the space? Not sure how well this will work, but I'm gonna try and fit a batavus reed block in there, the shape and size just kind of asked for it to be tried out. Wish me luck??

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Re: Jawa cylinder reed conversion

The holes actually meet right up dead center, the only thing is that the Jawas have 5mm studs. Thinking of re-tapping them out to 6mm, there isn't a ton of meat beside the stud holes with the reed block in mind, but I may just go out on a limb and try it out. See how cute this could be? Lil guy might just snuggle right down in there after some VERY careful dremel work :)

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Re: Jawa cylinder reed conversion

Did the deed and tapped both the intake and exhaust out to 6mm, I think there's still plenty of meat now that it's done, after measuring the reed block it doesn't seem like I really need to open the intake up side to side, looking good so far. Using these nifty hex-driven studs, easy to install/uninstall. Time to shape it and get this reed block to fit!

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Re: Jawa cylinder reed conversion

Definitely looks like it has potential! What to the ports look like?

Re: Jawa cylinder reed conversion

Dirty30 Dillon /

That's an ingenious discovery.

10/10 will watch along

Re: Jawa cylinder reed conversion

This is top content

Re: Jawa cylinder reed conversion

Kevin Bishop /

I am doing this to a hero kit for puch. Nice work! Maybe I should document work better. Sexy studs btw.

Re: Jawa cylinder reed conversion

Yeah just port for reeds and it'll rip.

Add boosts at 45deg towards plug and go go go

Re: Jawa cylinder reed conversion

You could bring it by and we could mill that area flat if you want

Re: Jawa cylinder reed conversion

Quality stuff

Re: Jawa cylinder reed conversion

Curious to see what performance improvement you get with this. I looked into this some time ago. I researched and read till I was bleary eyed. From what I read the reed performance depends on the window mod in the piston. Calculating this was way above my experience level. I'm hoping YOU figure this out and share. Go Jawa!

Re: Jawa cylinder reed conversion

This was one avenue I looked Into. There is a video out there of a shop testing on a dyno the before and after on a Chinese bike engine. They managed to "decrease" performance by adding the reed block.

https://www.ebay.com/itm/174238215514

I think there is a flatter one that could be adapted with a 1/4" standoff and an aluminum plate but I can't find it now. (edited)

Re: Jawa cylinder reed conversion

Lol

If you don't port for gains yes a reed might not help. I'm

But if you add boosts and 360 intake to the cases you can almost double the power with a good pipe

Re: Jawa cylinder reed conversion

Window the piston, add a boost and cut skirt to make a new port that feeds into the cases where the skirt was so you don't have to cut cases at all

Big fucking gains

https://mopedarmy.com/forums/read.php?7,4263596,page=1 (edited)

Re: Jawa cylinder reed conversion

JBOT, you need to educate me on this. Sean and I lust for fast Jawa.

Re: Jawa cylinder reed conversion

Yes, but it’s a secret right now. Hehe

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Re: Jawa cylinder reed conversion

Ben, you're killing me...

Re: Jawa cylinder reed conversion

You can throw a reed on anything.

Then port for big gains in whatever power band you want. Pretty easy actually

Re: Jawa cylinder reed conversion

> Frank Bailey Wrote:

> -------------------------------------------------------

> Ben, you're killing me...

I’ll start a thread when I get it assembled, mounted and running

Re: Jawa cylinder reed conversion

I have researched porting but the only simple thing to me is widening intake, exhaust and raising the exhaust a bit. Modifying transfer ports and changing timing escapes me. I'm willing to expand my understanding.

Re: Jawa cylinder reed conversion

Chop big hole in intake side of piston and add boost ports that go into the intake on the cylinder. Piston port cylinders can have boost ports too but they should not go into the intake. Piston ports can also have holes on the intake side of the piston, but they likely close the top and bottom of the cylinder/crankcase as they cross they intake port.

> Frank Bailey Wrote:

> -------------------------------------------------------

> I have researched porting but the only simple thing to me is widening

> intake, exhaust and raising the exhaust a bit. Modifying transfer ports

> and changing timing escapes me. I'm willing to expand my understanding.

Re: Jawa cylinder reed conversion

Vlado Vlado the jawa gurus Reed setup + other goodies https://mopedarmy.com/forums/read.php?1,3056166,3059005,flat=1#msg-3059005

Re: Jawa cylinder reed conversion

🇮🇹💦 Of the Loin /

You could maybe use those adapter plates I had made for V1 to slap a malossi Reed block on this thing.

On V1 polini even without modifying it the reeds make it quieter and spit less gas while not decreasing performance

But what the fuck is the deal with the plug

Re: Jawa cylinder reed conversion

Ϫ‡☄ಬ∞ ƀƖḬƝƊ ƤǂƿƎ ∞ಬ☄‡Ϫ - Hoke from Black Pipes Moped Gang /

this thread needs updated pls

Re: Jawa cylinder reed conversion

^^yeah another lost moped project that lost interest, put on the back burner and time is just reeding away...

Re: Jawa cylinder reed conversion

Sorry dudes I had to give my reed block away to someone who needed it, waiting for em to be back in stock so I can get back on this! It’ll go back to the front burner soon!

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