2-stroke performance engine - special JAWA piston repair

Good day again.
This video, effectively is a result of a slightly too specialised engine part that is not available in any stock. I had the choice between a lead time of 2 or 3 months for a new, expensive customised piston or a repair and machining trial, which ended up as special as the entire engine.
For those who want to do a similar repair: The bushing press fit was 0,03 mm (oversize) which should be sufficient to keep it position. As it is not a part under static load I’d never ‘glue’ it in position, like some do.
Thanks for spending some time on this channel, as well as for you positive comments.
Music in this video created by following artists:
Pavlo Butorin ‘Funtime’
Ricky Bombino ‘Cyber Technologies’
Mocha Music ‘Following Your Dreams’
Peter Sandberg ‚An Unforgettable Moment’

[@andreaslindner6559]

Servus! What a great pleasure, seeing old school, skilled, heartblooded toolmakers workin'...!!! We speak the same language around the world! Keep on rollin' Andy The grey bearded german toolmaker

[@Quiet.Light.Engineering]

💪🏼💪🏼💪🏼👊🏼☄️

[@2terry6]

I like Jawa and I'm happy to see how you work with she. Perfect job. You should be a teacher at engineer school and share your nice knowledge.

[@pavelvincenc5314]

Asi najlepší technik mechanik čo som videl skvelé nápady a riešenia

[@Sam-ob4of]

Glad you're back

[@Quiet.Light.Engineering]

👋🏻👊🏼😀

[@1978JonBullock]

The ingenuity and craftsmanship is outstanding. Also added bonus of hedgehog and cat's at the shop.

[@BAK87]

This was like watching piston surgery! Precise work with beautiful reward! Much respect for DIY approach. Cheers!

[@Quiet.Light.Engineering]

👊🏼😍🤟🏼😇

[@Darkrif1957]

used to be a great speed way bike engine , cheers from Australia

[@NurdRage777]

Vintage JAWA. A thing of beauty a joy forever.

[@Quiet.Light.Engineering]

👍🏻

[@jefflormans5441]

A home workshop with a cat, looks like heaven to me. Those Jawa's seemed pretty common back in New Zealand when I was a kid.

[@Quiet.Light.Engineering]

Thanks. Good information. That explains, why I saw pics of modified JAWA 559s racing on New Zealand tracks. It was hard to believe that they had been exported to NZ, even.

[@alanhampton1030]

They were built here for a period. ​@@Quiet.Light.Engineering

[@Quiet.Light.Engineering]

👍🏻

[@isickofit]

Beautiful repairs are improvements.

[@hffreebird]

I had tried the PB bush for the wrist pin before, unfortunately the machinery I have access to wasn't able to bore out the wrist pin bore true like yours, so ended up abandoning it, but watching your video gave me some new ideas on how to achieve that in a round about way. Thank you for staying on it.

[@Quiet.Light.Engineering]

Thanks. That’s one of the reasons why I make such videos. Sharing ideas to keep old hardware alive.

[@williamllorens2141]

What a fortunate man you are. Have all the best tools to the job right 😅😅😅now

[@Quiet.Light.Engineering]

Thanks Mate. You a right, I should have little reason to complain. Tools though, one can hardly ever have enough.

[@AutoBeta2T]

Really cool video with some great machining techniques. Thanks for sharing 😊

[@Quiet.Light.Engineering]

Glad you enjoyed it

[@Jawar90]

Krásně si s tou Jawkou hraješ 🙂 Opět dobrá práce 👌

[@Quiet.Light.Engineering]

Thanks for your feedback.

[@waldemardworezki1710]

Danke für das super Video...ich als 250ccm 2Taktfahrer kann ne Menge lernen. ❤

[@Quiet.Light.Engineering]

👋🏻👌🏻👍🏻

[@Neonthon]

Fantastic video! Enjoy the new piston

[@Quiet.Light.Engineering]

Thanks again!

[@zcomputerwiz]

Very nice work! Thank you for documenting the process and showing us your critters!

[@Quiet.Light.Engineering]

Welcome, Sir.

[@Oldmz]

Wow ❤...just wow 😎!! The amount of work and attention to details is really brilliant ❤❤

[@Quiet.Light.Engineering]

Thank you! Cheers!

[@william1389]

I love this kind of work! 👍💯

[@Quiet.Light.Engineering]

Same for me, too.

[@mzzybex6754]

Well done, well done, amazing job!

[@Quiet.Light.Engineering]

Thank you!

[@cPetan2]

Those marks on castings are probably made by air pump which fell off its holder. Every Jawa 559 has it.

[@Quiet.Light.Engineering]

For that, the look and position is too similar on all the casings. And normally, the carb was covered.

[@cPetan2]

@@Quiet.Light.Engineering because of the cover nobody noticed, that the pump fell off. Here is talk about it www.jawamania.info/poradna/detail.aspx?questionid=68794

[@cPetan2]

@Quiet.Light.Engineering because of the cover, nobody noticed that the pump fell off. There was a topic about it on Jawamania.

[@Quiet.Light.Engineering]

Thanks. That’s interesting and probably the truth. Never seen such a pump though and how and where it was fit to the engine. Must have been very small…

[@massimilianozanoni767]

Love you Channel and your videos! From Italy

[@Quiet.Light.Engineering]

Buona giornata, grazie mille.

[@Jawir287]

great job, best regards from Ukraine.

[@Quiet.Light.Engineering]

👊🏼💪🏼

[@JAWA360Georgs64]

💥💥💥💥💥💥💥💥

[@Quiet.Light.Engineering]

Thanks Georgi.

[@bobg3034]

Awesome fix!

[@Quiet.Light.Engineering]

Thanks 👊🏼

[@SinsBird]

Don't worry about video aspect ratio, I got this video recommended, so apparently this is fine for youtube.

[@isarwasser5271]

Ich liebe Dich, ich meine Deine mechanischen Fähigkeiten! Grüße, Isarwasser.

[@Quiet.Light.Engineering]

😍

[@s.a.f.r.a6403]

The wear marks on the Jawa 559 casings that your talking about is cause by the drain bolt on the carb its is quite a common occurrence on multiple different branded 2 strokes with a similar design it happens due to vibration

[@Quiet.Light.Engineering]

Are you sure? I really don’t get it. The drain cap on the stock Jikov is ~10 mm above the casing.

[@fjjunker8388]

A very good work.

[@Quiet.Light.Engineering]

🤟🏼👊🏼👍🏻

[@leonardarola]

Ohh man. Well, great work, but I don't know if I would reuse said piston. It doesn't matter how well the repair is made, once broke, the structural integrity is changed forever. Thanks for sharing.

[@Quiet.Light.Engineering]

No worries. I made the original drawings of that piston. There was some margin left.

[@leonardarola]

@@Quiet.Light.Engineering Alright. I understand that.

[@williamllorens2141]

And the knowledge needed ❤❤❤❤

[@frankierutherford1888]

Well done

[@Quiet.Light.Engineering]

👍🏻😉

[@viorelindeamna6405]

Bravo !Bonne travaille 👍

[@Quiet.Light.Engineering]

Gazie mille.

[@MarcoTernavasio-pv3ec]

I hope you use it just like an asher!!

[@antipod175]

What are these yellow marks, two on the cylinder and one on the engine block?

[@Quiet.Light.Engineering]

Measurement stickers for temperature. Stuff one can buy.

[@PeVeln]

On my untouched jawa the piston pin is tightly pressed in the piston. What is the difference when its loose or tightly fit?

[@Quiet.Light.Engineering]

On a pressed pin you have to rely on the conrod small end bearing, as the pin will most likely remain without movement even if the piston is hot and the bore wider. On an interference fit the pin will form a second (pair) of bearing with a thin layer of oil in between pin and piston bore. This helps “unloading” the needle bearing should it see e.g. harsh operation. I often modify old pistons to give them an interference fit by honing. Also, it facilitates assembly.

[@ordogh2002minecraft]

How did you convert the 559 engine to have a separate lever for starting and shifting?

[@Quiet.Light.Engineering]

That’s a rather easy thing to do. You need corresponding Perak or 579 parts.

[@ManO0waR]

Why didn't you heat the bushings into the piston? (sorry for the spelling - I'm using Google translator)

[@Quiet.Light.Engineering]

Wouldn’t work without a cooling tool for the bushings. Bushings heat up too fast, or required temperature delta is pretty high. Didn’t want any risk for the piston.

[@ManO0waR]

@@Quiet.Light.Engineering Understood thanks

[@flyingfish7073]

Hey, im doing a JAWA 350 638 build myself, what are your thoughts about putting on RD350 carbs from Yamaha on the engine, also maybe fiting some reed valves too? Also, when I was disasembling my engine, the piston pin was very tightly in the piston, I had to punch it out, is that normal or is that bad?

[@Quiet.Light.Engineering]

Old pistons have press fit pins. This is normal, but today any performance piston I know comes with an interference fit. Converting the JAWA into reed valve intake makes a good difference for mid and low end performance. Top end may also benefit from larger carbs.

[@flyingfish7073]

@@Quiet.Light.Engineering I see, and well... Could there be a plausible way of filling the reed valves from the same RD350 engine, onto the Jawa engine, by not machining the cylinders to specificaly fit them, but rather to make an adapter that would bolt onto the existing screws on the cylinders? Im just getting into 2 stroke basics so I dont know if lenghthening the intake manifold would affect prefformance. Also didnt mention, but amazing 250 build!

[@Quiet.Light.Engineering]

The extended length will have no effect you can feel on your engine. You may want to increasing exhaust and transfer time and getting windows slightly wider without changing transfer angles too much. There are several good books on this. Better get one first.

[@flyingfish7073]

@@Quiet.Light.Engineering Alright, will look into it. Big thanks for the info, ill get to studying then.

[@hedning003]

why use a centricator when you have a dro? dont you trust the dro?, or pherhaps dont have a small edgefinder?

[@Quiet.Light.Engineering]

I just like using the good old centricator. And it’s also fun for the centricator to be in operation once in a while.

[@hedning003]

@@Quiet.Light.Engineering well, i can agree whit that - mine is probably seezed 🙃

[@akos127]

I love that you made that old fart running like a super star! I am in a little bit of a similar shoes without the machinery in my single garage. I saved an old CZ 250 twin for modifying purpose, but guess, well you don't have to guess you know, because short of financial issues and spare time having hard time getting off the bases. I collecting interesting parts and managed to get a 350 Jawa engine, 38 Mikuni, put an SV1000 front end into it, got a double swingarm to extend, strengthen and lift the rear of the bike up at least as much the front, but having issues to put myself into spend so much on the pipes, cylinder work, crank work, pointless ignition system, and so much more into it and then still stuck with a shitty clutch and transmission. I was gonna get a 500 Ninja or a crashed Aprilia 660 that come out cheaper with carbs. What do you think?

[@Quiet.Light.Engineering]

Getting an old 2-stroke JAWA fast and reliable is a difficult task. I’m doing it just for the technical sake of it Mate. And I want it looking like it looked 60-70 years ago. At least as close as possible. That’s my spare time profession. Can’t recommend the right path for you.

[@andrewallen9993]

@@Quiet.Light.Engineering My old 350ts and tramp while not fast are reliable as they are factory stock. Good luck with yours though and good fun at the traffic lights.

[@t-works3643]

You're sick! 😁 I was waiting for the whole 4 months for the new video. Why did you ditch tune exhausts? Thank you!

[@Quiet.Light.Engineering]

I like using the stock exhausts. Best torque at low rpm. The racing pipes make the bike aggressive and louder.

[@mattivirta]

you need buy same book what i have, how calculate and increase jawa power, tell all what need do cylinder,piston,exhaust garb, etc and all calculate formulas how make ewery size engine better exhaus. i give this book i has 13Y old and then modified my 49cc/50cc buch moped motors first, genuine max speed has 50 Km/h and after cork max speed has beak 160Km/h. and has my first repair engine, second husgwarna dirt-bike i modified has lot better. calculate and make all cylinder holes, piston, exhaus totally new. hand tools in garage made all 14 Y old boy. now i have 65Y old retiree engineering.

[@user-qt9vs2nj8e]

​@@mattivirta как называется эта книга

[@doritosmanlp9767]

I think that the wear is made from some tools due to the main jet position in the original carburetor.

[@Quiet.Light.Engineering]

But there is lots a play, if not a large gab in between original Jikov carb and casing…

[@1crazypj]

Is that a modified cylinder with bolt on reed block or a later development from factory? I don't think I've ever worked on a JAWA, CZ or MZ that didn't have rumbling main bearings. We used to change mains on MZ at first service (1970's~80's, ~500 miles) Personally, I would have bored/reamed piston and fitted 'top hat' thin wall bronze bushings almost exactly like you did. (I did train as precision machinist before returning to motorcycle dealer servicing) That's very nice micron reading small bore gauge.

[@Quiet.Light.Engineering]

Hi, it‘s a heavily modified stock cylinder. See other video „how it was made“ if interested.

[@user-pw2sg9hu7f]

Krásna práca 👍nádherna motorka 👌. Tiež mam Jawu 559 a jazdim na nej každy deň . Vidím že si odborník a baví ťa to. Može vedieť odkial si? Len zo zvedavosti. Ďakujem🙏 . Ja som so 🇸🇰 Slovakia🇸🇰

[@Quiet.Light.Engineering]

Best Regards to Slovakia! Keep your 559 running!

[@user-qt9vs2nj8e]

how to find you on social networks I want to assemble the same motorcycle as yours 😊

[@Quiet.Light.Engineering]

This is my social network :-)

[@kamikadze242]

😀Hei, i was waiting for cylinder build video, but its better than nothing😂. What balancing factor you used for crank?

[@Quiet.Light.Engineering]

Sorry to say that will take more time. Maybe next year? God knows. Unlike other people here on the platform I may make a video when I have good reason to do so. 65%.

[@kamikadze242]

@@Quiet.Light.Engineering 😀but your video is good quality. I don't need to skip anything. Its pleasure to watch, keep going and posting.

[@SB-vb8ch]

Not a lot of material around that gudgeon pin bore.

[@Quiet.Light.Engineering]

That’s why the bushing is on ~0.5 mm thick. Will be fine though. It’s enough still.

[@motobiglove]

Шикарно!! Какие у вас мысли про усиление коробки передач?

[@user-gy8pz2jc7j]

Про это см предыдушие видео

[@motobiglove]

@@user-gy8pz2jc7j Да, уже посмотрел, спасибо! Вы делаете шикарную работу!!! Вы говорите по-русски?

[@wacupanic]

Great job! Planning to sell DIY Engine kit? Hello from Ukraine!

[@Quiet.Light.Engineering]

I’m not planning anything like this. Do you think it makes sense? Most likely nobody would be willing to pay for the work. This is a JAWA or other old low cost vintage work horses not a dentists or lawyers Harley where 6000 or 8000 bugs don’t make a noticeable difference.

[@snrsmh]

Hi bro, you should use the video format 16:9

[@Quiet.Light.Engineering]

You are probably right Mate. Maybe as I’m as old fashioned as my hardware suggesting other classic formats.

[@snrsmh]

​@@Quiet.Light.EngineeringYour video is excellent, its only flaw is the screen format.

[@Quiet.Light.Engineering]

@@snrsmhWe will have to live with it as is.

[@user-jl8rj2ns2b]

Возможно было бы проще изготовить ремонтный палец увеличенного диаметра, и под него расхонинговать отверстия в поршне и в верхней головке шатуна. Подшипник при этом остаётся прежним.

[@Quiet.Light.Engineering]

You are right, but I didn’t want to strip the crankshaft for proper machining of small end. And getting the new pin 100% right without any risk (hardening…) is not a given.

[@isickofit]

Ring a ding ding, not ring a ding dang..

[@SB-vb8ch]

Nice repair. Sounds sweet, is the hissing during kicking over an automatic decompressor? Sounds like compression leaking from somewhere.

[@Quiet.Light.Engineering]

Decompression valve. It was required. If interested see other videos.

[@tomast9034]

i would put the piston on the sun and the rings into the freezer.

[@Quiet.Light.Engineering]

We’d need a pretty warm sun that day 😀

[@tomast9034]

@@Quiet.Light.Engineering ok if not enough onto the dashboard and the car on the sun that will heat up :D

[@user-ng4ux7um4u]

откуда у тебя столько высоко точного и дорого го оборудования и инструмента ?

[@Quiet.Light.Engineering]

There isn’t much special mate. Mainly this is all normal tool makers equipment. Often is pretty old and used stuff in good condition. Just bought second hand. Lathe and milling machine are average level quality asian made.

[@My_Gaming_Mind]

The thumbnail really made it look like you were going to weld up the old broken piston 💀

[@Quiet.Light.Engineering]

Or even bond too… 😉 a certain level of irony is tolerable, hopefully. If I would take those technical things too serious, I shouldn’t be doing it any longer.

[@user-jl8rj2ns2b]

Приятного аппетита ёжику

[@balintmagyar5362]

Bár csak a jawa gyár is így csinálta volna!

[@Quiet.Light.Engineering]

🥹. They didn’t do too bad for their time and technology. JAWA vehicles and engines can last pretty long.

[@user-gy8pz2jc7j]

Цилиндр не успевает охладить такой объём у вас всё правильно и акуратно но соотношение расчётов и как вы едите гробите технику включая коробку теперь поршня

[@Quiet.Light.Engineering]

Is that probably because it’s made in the West, hence must be bad? 🙄

[@bobg3034]

Where is the oil!

[@Quiet.Light.Engineering]

?

[@bobg3034]

@@Quiet.Light.Engineering I just did not see any 2 stroke oil on any parts when you tore down your engine. Was it oil starvation?

[@Quiet.Light.Engineering]

I think video cutting technology allowed me to wipe it off. Otherwise I‘m using 50 / 50 low flash point and high flash point oil, so there isn‘t that much visible oil. The low flash point one seems to disappear quickly indeed.

[@mattivirta]

i has young boy some jawa 250cc and has worst bike and engine what ewer i has all my life. newer not keep right ingnition and alltime need repair many.

[@Quiet.Light.Engineering]

That’s right. Sometimes old JAWAs can drive their owners crazy. Even today

[@AddictedtoProjects]

Pure engineering p*rn! :)

[@Quiet.Light.Engineering]

😬🤟🏼👊🏼

[@akbarudinmajid]

I am from jawa😂

[@Quiet.Light.Engineering]

👌🏻

[@germany-cars6058]

Increíble 🫢💪💪💪

[@russbernard8666]

The wrist pin clips won’t work now

[@Quiet.Light.Engineering]

The clips inner diameter covers the pin pretty well still, also they are “hook type”.

[@russbernard8666]

You should have just opened up the con rod end and make a custom wrist pin

[@Quiet.Light.Engineering]

Maybe, but getting the wrist pin right and perfectly hardened is not a trivial thing to do.

[@russbernard8666]

@@Quiet.Light.Engineering 52100 steel.

[@annpeerkat2020]

1:13 "let's check for anything obviously wrong" removes cylinder head...yes but then removes barrel without first checking piston slap in cylinder? I guess you knew what you were going to find perhaps... or knew you were going to be able to measure piston/rings/bore accurately with gear. Bush mechanic me (not having much in the way of measuring gear) would always wiggle the piston head in the bore and scratch my head first, before taking off the barrel. I'm not trying to suggest your solution is wrong.... you're far more skilled than I have ever been..... but I'd be worried that if the brass bush turned a bit in the journal, the lubrication hole would block and things might get nasty in the top end. If I had a time machine, and video'd my first exploration of top end internals, and repair, of an old bsa 250 that I'd seized about 4 times trying to get home up a long hill (a longgg time ago).... I think folks would have been horrified by my use of hammer, chisel, hacksaw and file.... removing a broken ring and cleaning out the ring slot/lands sufficiently to fit a new ring in. The poor old beast ran for a fair while after that, until I upgraded to an early 60s C92 honda benly.

[@Quiet.Light.Engineering]

Thank for your detailed words. I’m not quite sure what your recommendation is as to what could have been done better. Get a feel for the piston / cylinder clearance? That doesn’t help me much. I subsequently measured as always and found it satisfactory.