Complete rebuild of JAWA 207 Babetta .305

Luke Micallef /

Jun 23, 2020 12:22PM

Hi all, so this is my first post ever on here. Recently got my hands on a jawa Babetta 207.

305 I think. Anyway, it’s from 1982/83 and only has 7miles on the clock. It has a bing carburettor. Which I know is unusual for these bikes.

I’m planning on completely rebuilding it as a project for myself. Never rebuilt a bike before. Starting off with rebuilding the engine completely. Hopefully will be able to crack that without much help, found most of the spare parts il need. But I will be back and forth for some expert advice. Starting off with the cylinder block.is it normal to have 2mm gap without the gaskets in place? Any and all help will be greatly appreciated.

Re: Complete rebuild of JAWA 207 Babetta .305

Frank Bailey /

Go to branch

themechanic

Jun 23, 2020 01:08PM

If the engine spins freely, why not just run it?

Re: Complete rebuild of JAWA 207 Babetta .305

kenny s /

kennys

Jun 23, 2020 01:28PM

You mentioned that you want to rebuild the motor. Why? If you can't get it running the problem is most likely an external problem such as carbs fuel tank thyristor and spark plugs. That 2mm gap is fine. Do you want to rebuild that motor for speed? Mine was rebuilt and I went from a top speed of 25 mph to 29 mph. The 210 engine is so much easier to tweak for speed.

Re: Complete rebuild of JAWA 207 Babetta .305

Luke Micallef /

lukem

Jun 23, 2020 01:49PM

Yea the motor spins freely but at 37 years old I’m guessing all the seals are shot. For me it’s more of an engineering exercise. To look back when it’s done and say yea, I rebuilt that from the ground up. Figured getting the engine running before I do all the shiny bits was Probably the most important.

Next item of help. The battery pack for the blinkers/lights.

Anyone know where I can get a these batteries rebuilt/alternative?

And a new rubber mounting for the housing.

Re: Complete rebuild of JAWA 207 Babetta .305

Leo Heyman /

leoheyman

Jun 23, 2020 02:08PM

if its running DO NOT rebuild the engine yet.

its easier to trouble shoot a running engine.

when i rebuilt my 207 the engine was very hard to get apart.

i needed a case splitter.

it is a nice little engine

well put together.

Re: Complete rebuild of JAWA 207 Babetta .305

Frank Bailey /

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themechanic

Jun 23, 2020 02:51PM

> Leo Heyman Wrote:

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

> if its running DO NOT rebuild the engine yet.

>

> its easier to trouble shoot a running engine.

>

> when i rebuilt my 207 the engine was very hard to get apart.

>

> i needed a case splitter.

>

> it is a nice little engine

>

> well put together.

This is solid advice.

Re: Complete rebuild of JAWA 207 Babetta .305

Luke Micallef /

lukem

Jun 23, 2020 04:14PM

Would the seals And gaskets be any good after 37 years??

Re: Complete rebuild of JAWA 207 Babetta .305

Ryan Graeme /

bigrvg

Jun 23, 2020 05:06PM

You'll find out and if they are not, you'll be rebuilding anyway.

Re: Complete rebuild of JAWA 207 Babetta .305

Leo Heyman /

leoheyman

Jun 23, 2020 05:14PM

of course the seals and bearings are bad

37 years old they are ready to fail

ride it around and let them fail

most likely the crank seals will let go first

the 207 engine takes more seals & bearings that most

moped engines

Re: Complete rebuild of JAWA 207 Babetta .305

P D /

pdcomm

Jun 23, 2020 05:33PM

I'm running the original 36 year old bearings and seals in my FA50 .

But , those are of Japanese descent . ;)

Re: Complete rebuild of JAWA 207 Babetta .305

Leo Heyman /

leoheyman

Jun 23, 2020 10:40PM

Japan makes some very nice bearings.

unsure of the Czech bearings

bet they use German bearings

Re: Complete rebuild of JAWA 207 Babetta .305

Born to be WillD /

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willd

Jun 23, 2020 11:17PM

I rebuild a bike if it's and engine I haven't done yet, just for the exercise and info.

it's a hobby, dig in! Sometimes it feels good.

I would say though you're definitely much more likely to create new problems than you are to resolve any, but if you're doing it for the curiosity go for it!

Re: Complete rebuild of JAWA 207 Babetta .305

Luke Micallef /

lukem

Jun 24, 2020 12:50AM

Yea that’s kinda the idea. Iv never rebuilt an engine before. I’m quite knowledgable and handy with tools and industrial processes. And any specialist stuff I can go to my local garage to be done, like splitting the case or pressing bearing/shafts back on. I did my research, found out most parts are readily available and I thought this would be a good learning experience. But yea perhaps a few of the others are right. Get it running as is, and then if it fails well I’m rebuilding it anyway.

Pic showing an original 7 miles on the clock!

Re: Complete rebuild of JAWA 207 Babetta .305

Born to be WillD /

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willd

Jun 24, 2020 01:29AM

more than likely that's a pic showing that your speedometer/odometer broke at 7 miles...

Re: Complete rebuild of JAWA 207 Babetta .305

Sean Mohoot /

chugdugdadug

Jun 24, 2020 03:32AM

Never hurts to do bearings and seals! I have a 207 apart for the first time right now and yes it is a fun learning experience to see what's inside and know that it's good to go after replacing cheap parts like bearings/seals. Hopefully the harder to find or more expensive parts like top end/crank are in good shape, not sure if you have the bronze wrist pin or roller bearing, the latter being stronger and longer lasting. Otherwise the other issues could very well be electrical as I'm sure you've read, the classic thyristor problems. Luckily there's a few new replacements to take care of that!

Re: Complete rebuild of JAWA 207 Babetta .305

kenny s /

kennys

Jun 24, 2020 03:38AM

Also that turn signal light box is probably not needed. The bike has 4 coils. You have more than enough electric. Just take apart the alternator and connect wires to the correct coil. If you need 12 v then buy one of them step up voltage converters.

Re: Complete rebuild of JAWA 207 Babetta .305

Luke Micallef /

lukem

Jun 24, 2020 06:47AM

No it actually works. It was sold as 7 warranted miles, Last time the bike was taxed was 1983 and hasn’t been on the road since, And the odometer ticked over to 8 miles while IV been rolling it around.

Re: Complete rebuild of JAWA 207 Babetta .305

Dave Thacker /

crafted

Jun 24, 2020 07:23AM

I don't know if those are D's or Sub C cells. I have an RC electronics company and we build batteries. However, I noticed this online. What you have there looks like NiCad. If it's D size it would be quite expensive to build. What you see below is an insert for an emergency light and would work fine if your cells are in fact D size batteries.

https://www.batteryspace.com/NiCd-Battery-Pack-6V-5000mAh-5xD-hump-for-emergency-light.aspx

Re: Complete rebuild of JAWA 207 Babetta .305

Leo Heyman /

leoheyman

Jun 24, 2020 08:00AM

if you only have 7 miles on it then the thyristor is defective on it.

replace that 1st

problem solved

someone did a Jawa Babetta 207 rebuild on YouTube

totally rebuilt the engine

they could not get the bike running

video never shows the Jawa running

probably ignition and probably the thyristor

do that 1st

Re: Complete rebuild of JAWA 207 Babetta .305

Luke Micallef /

lukem

Jun 24, 2020 09:09AM

Yea I seen that, American guy over 3 episodes. Most other vids are Eastern Europe and can’t understand shit, but get the idea from what’s happening.

Re: Complete rebuild of JAWA 207 Babetta .305

Luke Micallef /

lukem

Jun 24, 2020 09:19AM

Hi David. Great find Btw. I’m in the uk so will try to find the same here.

On the original battery it has 4 terminals. Guessing, 2 input and 2 output. What you think?

MOPED ARMY

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