Jawa info needed

[lingeringstin...]

I have sort of an MZ. Most of my bike isn't even MZ anymore as I don't really care what the rest of the bike is made out of, but the engine needs to work.

I have experimented in wild and wonderful ways with MZ engines over the years to see why they were crap and have adapted and modified things over time until now I can build one that's reliable and long lasting, albeit with a bunch of "you can't do that" modifications that have the purists in fits.

But NOW the damned things are "vintage" and spares are becoming too expensive so I've been considering other engine options, and I do love primitive two strokes. For instance gearboxes are currently going for like a hundred quid secondhand and the cost of new stuff is just stupid.

Basically MZ's are going the way Bantams did about 20 years ago. At one point you couldn't give Bantams away. They rusted away in blissful ignorance and people raced them and used the tanks to make choppers, but a few years later leftover Bantams were changing hands among midlife crisis restorers for silly money and they instantly evaporated into thin air.

You never see a Bantam out on the roads now unless it's some ultra restored nerd bike that only comes out twice a year for vintage bike shows whereas I ride pretty much every day all year long over vast distances almost never seeing another MZ on the road and even then they'll be perfectly restored factory abominations ridden by vintage flat cap bike nerds who congregate at tea huts in the summer to mutter and sneeze and discuss factory paint and tank logos and who, upon seeing me pull in on the way to a rally, descend upon me like a flock of staggering gray bewhiskered zombies, gesturing at my bike with chinhanger pipes and mumbling and demanding a lengthy chinwag about BVF carbs and 6 volt ignition and whether a 7 or an 8 NGK spark plug is better for the 35:1 or is it 50:1 premix oh hell I really couldn't give a toss because my 12v bike has Suzuki 380 points and an SU carb and burns diesel and uses some random spark plug I probably picked up at the roadside and oh GOD they've fitted Pneumant tyres, the ones I call "ointments" because they're totally bleedin' slippery in wet OR dry conditions, in fact if you fit those miserable tyres to your bike just like the factory did 40 years ago don't be surprised if your bike doesn't just randomly flip over from time to time even when parked up due to lack of stationary grip, but I digress...

Basically, MZ are going away like Bantams did now and I'm not prepared to throw stupid money away on them.

Have been considering a Jawa 350 engine and would like to know the short answers to what breaks and why.

I'm not concerned about little things like bad bearings and oiling problems or stupid carbs, ignition and exhaust, I can sort that stuff out. I just want to know what engine mechanical weak spots there are so I can decide if they're worth messing with. Jawa engine spares seem to be readily available and cheap but it's no good if for instance they have a design flaw that continually breaks gearboxes or clutches fail on a regular basis or something.

[MarJay]

Stinkwheel has some experience in this area. His advice to most general users is 'Don't'. That said, his was rideable, even if the barrel heights were totally different and things like that.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[pepperami]

Jawa/CZ ? CZ/Jawa ? having owned a 350 twin, a CZ 125, and a CZ 250 crosser, the biggest issue I had with them was the pony/weedy clutch plates.
Never had a gearbox issue
However, the kickstart return spring did snap on the CZ 125 and that was a swine to put right

Not much help but my

https://www.youtube.com/watch?v=3DwVtTeW8I8

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I am the sum total of my own existence, what went before makes me who I am now!

[Vincent]