JAWA 2-stroke power tuning 350 cc / 559R (part 1) 

Thanks for the very friendly words.

Thanks Samuel, those are very personal words. Yes, those times are gone, but there is enough material around for a little fun.

You took me to the 70s

@@Anandkumar-hz8mn❤😊👊🏼

добрый друг, большое спасибо за эти слова.

Thanks for the friendly feedback.

Good luck Peterman!

If you do this, you surely gonna fly ✈️✈️👍👍

Thank you Mate.

Thank you.

Thanks. Its also great fun to ride. I’m glad the frame appears able to cope with the power. There is certainly more stable bikes on the streets but mostly less cool :)

@@Quiet.Light.Engineering I think, the Jawa frame is not that bad. I have MZ 251 and I had to reinforce the main frame. Originally its made from paper :-D

Thank you, Mr. Cleaver. Yes, good summary - that was the project. Only polishing I didn‘t do inside the engine. At least not on purpose. That doesn‘t really help the performance. Smoothing corner etc. is sufficient.

Thank you, Sir. More to come. Regards.

Thanks Mate! 😎💪🏻👊🏼🤟🏼

Glad you liked it!

Danke sehr freundlich. Ich freu mich auch immer wieder mal das Filmchen anzuschauen. Die Hunderten von Arbeitsstunden sieht man dem Bike nämlich nicht mehr an.

@@Quiet.Light.Engineering wird das ganze denn eigentlich noch regelmäßig bewegt?

Thanks Mate.

💪💪💪🤟🏼👍🏾

Did you also achieve 50 Nm?

@@Quiet.Light.Engineering Probably close to 50 Nm. I had a problem with constantly breaking the CZ chain adjusters, usually within a few kilometres of fitting a new one. I eventually solved this by drilling one out and attaching it with a high tensile bolt. The engine then proceeded to slightly bend the adjuster bolt mounting on the swinging arm, but never broke it. I have the only CZ with a 30 degree chain adjuster mounting lug on the swinging arm. Clutch plates lasted 6 to 8 weeks with daily use. I eventually used 1988 Suzuki GSX 750 R springs (they fit) and the clutch would last for as long as 14 to 16 weeks in daily use. Chains were another issue. I tried an Izumi heavy duty 428 chain, but it was destroyed quicker than the Reynolds & CZ chains I was already using. I did the work on the engine during a rebuild at 54,000 miles, using an already fast 1975 CZ 350-623 engine from an Italian market Aprillia headlight version. It had an oil pump slot on the crank, but never had an oil pump casing because CZ never put the CZ 250-471.2 into production. I had the cylinders bored out the cylinders to 58.5mm., replacing the stock Asso Werke forged pistons with 2nd oversize Asso Werke forged pistons. The exhaust ports were raised 3mm. and the transfer ports by 2mm. with the "hump" in the transfer port bend ground out to direct the fuel mixture higher into the cylinder. All the cylinder port tunnels & the carb manifold tunnel were polished. On the good advice from a friend's boss, who drag raced cars, the bearings were replaced with more expensive low friction rated SKF versions (I learnt that bearings have a friction rating). The rear brake was changed to a TLS unit and both brakes fitted with Ferrodo AM-4 competition shoes. The pipes are and still are Abbey Performance items marketed for the CZ 250 & CZ 350 in the late 1970's & early 1980's. They use an interesting non-straight through silencer design. The sprocket ratio was changed to 19:52 because the bike had a nasty trait of lifting the front wheel, slightly, when powering out of a corner in 2nd gear on the previous 17:52 ratio. This didn't quite cure the issue but made it less shocking & more controllable. Installing longer CZ Trail forks and Koni Dial-a-Ride 320mm. rear shocks nailed the unwanted power wheelie issue The bike is currently sat on my drive with the engine out, at 79,800 miles, in pieces after the sprocket bearing wore out, causing the top gear selector fork to melt (no 4th gear). I last rode the bike in August 2020. Gear change speeds are: 1st to 38 MPH. 2nd to 67 MPH. 3rd to 78 MPH. 4th to 107 MPH.

Andy, with all the extreme values you achieved: what sort of chain did you use for the primary transmission from crank to clutch? Knowing that is a wear point on JAWA I’m curious how you overcome that…

@@Quiet.Light.Engineering can you send me the Exhaust Port Timing along with the Transfer Port Timing

They revived the Jawa brand in India last year.

@@SurajSinghTomarArya looks like a jawa ,but moto morini engine

Go for it. It‘s never too late Eric.

Thanks Josef. And its great fun to ride that bike now!

Welcome Petr. 🇨🇿🇨🇿🇨🇿🚀🚀🚀

Thanks for watching!

Thanks Mr. Cooper! 👊🏼👍🏻🤟🏼

And it almost drives like one.

Thanks for your feedback.

Thank you, it‘s was almost intended also, to get a movie out of this technical documentation of a change in engine character.

Thanks mate, for the very friendly words.

🤭🤭🤭

Good for high load, bad for high speeds. This was a standard method before the 1960s.

You are welcome, Sir.

🤟🏼✊🏻🇵🇱👍🏻

😀👌🏻👍🏻

Sozusagen.

Yeah, and basically requires a screwdriver, two spanners and a file only! 😉

Thanks Phil. The carb cover belongs to the bike an must stay. Unfortunately the new carb is way too big, which is why the cover looks like it looks now…

@@Quiet.Light.Engineering Which Carb is it brother?

Thank you for the feedback.

👋🏻👋🏻👍🏻👊🏼💪🏼

Thanks Stanislav. Nice story. Greetings to Slovakia 🇸🇰🇸🇰🇸🇰

Thanks for watching. 🇵🇱 👍🏻👍🏻🤟🏼

Cпасибо большое товарищ! 🤟🏼👋🏻😉

That’s right Martin, that’s right. 😉

👍🏼👊🏼💪

@@Quiet.Light.Engineering срезал маховик, тяга на низах пропала и мощность сместил на высокие обороты.... Стал мотоцикл для гонок по прямой)))

@@ЮрийБесфамильный-б6е будто это плохо

Thank you! Cheers! 😮

Danke! Grüße nach Ostdeutschland!

Thanks Mate.

Thank you Roman for the friendly feedback. Yes, brakes and frame stability are an issue, but this is not really used like a race bike.

Hello. The 78 mm piston was specially made by Grand Master Wahl / Fellbach, Germany. Some more details can be found here: forum.jawafreunde.de/forum/index.php?thread/22776-projekt-jawa-573-ultrasport/

Thanks Jaroslav 🤛🏼👊🏼👍🏻

Thanks. Yes, it a nice vintage model. And still not too expensive to get one.

Thanks. All the best for your own project.

Sure: 2,5 mm left.

Welcome Sir. The result shown in this video wasn’t my first work. Failure happens on the way. Just don’t give up.

Well, isn’t it simply emotional to spent hundreds of hours for an old, long retired bike that almost feels like a race house now? 😉👌🏻

Thanks. I used normal high quality C3 bearings and a FAG NJ305 X-Life bearing for R/H crank side. A NJ bearing made in India by the way.

🥰👊🏼👍🏻

Thank you, Elizabeth.

Спасибо 👊🏼💪💪

Hello. Thanks for you comment. The gears from a „Libenak“ model I use now seem to work fine so far..

👊🏼🤟🏼👌🏻

True, a single exhaust is more simple to calculate. However resonance length is given and the same. I had good results with two chambers using the diameter area per each section. Interestingly the result was also good when putting on two completely different exhausts on either side. The reso band was soft but the width really good.

Yes length is the same, sure leaves a lot of room for experimenting on diameters. My engine was a bit different, two cylinder with two shared exhaust ports. So i was trying to develop a 1/2 volume 2 cylinder pipes. I like your reed block adaptation, very nice. Looks almost factory. The ports you put above look good to. Nice yamaha looking piston windows also.. I did the same on a piston port Bultaco back in the 80s and developed a pipe for that.

Danke. Ja, die alte Dame macht ganz schön Druck. Mit ordentlichen Resodosen jetzt allerdings sogar noch mal mehr…

Mille grazie. Twin engines I do not support currently. Sorry.

Thanks. The more modern version of this old JAWA gearbox which failed after the first tests was simply not made for such a high single torque. Many some bad luck for a piece of bad quality on top…

Thank you! Cheers!

Danke für das Lob!😊

Thanks for watching and comment.

🤟🏼👌🏻👊🏼💪🏼💪🏼🚀🚀🚀

Hi. A Keihin PWM38.

Thank you Mate.👋🏻✊🏻👊🏼

Thanks George.

Thanks for watching. The piston machining was purely for weight reduction. There was too much meat before.

@@Quiet.Light.Engineering How did you conclude that the bearings could hold the power? I see in the video that you are measureing the needles in the bearing, what did you ude that measurement for?

I‘ve bought and used single piece rollers. One must ensure that diameter difference is less then 0,002 mm to make them taking the load all the same. Hence, the measurement at controlled temperature was for quality reasons.

👊🏼👍🏻💪🏼

Piston has 78 mm. Specially manufactured in Germany. New sleeve required too. Regards

@@Quiet.Light.Engineering that's a lot of effort, let me know if you need any cosmetic parts, I have some.

For 559 70 mm piston can be used from Modell MZ ETZ 250. However they are heavier (80 to 100 g more) and crank may need to be adjusted at balancing holes.

@@sivaneo1855 what Parts do you have for YezdiRoadking Motorcycle

Hallo Herr Dr. Turbo L., das Rollenlager kann: 1.) etwas mehr Kraft vertragen 2.) unterschiedliche thermische Dehnung von Stahlkurbelwelle und Alugehäuse bei Festeinspannung abtriebsseitig ausgleichen, da Innenring verschiebbar 3.) Hauptgrund: ermöglich es den Motor konstruktionsbedingt (und nach Nacharbeit an den Passbuchsen) mit zwei Fingern zu zerlegen, ohne Drückerei, Wärme oder gar Hammer. Grüße S.v.S.