Batavus HS-50 fix up

Hey guys, been outta the moped game for a few years but recently moved back home and found my old bat collecting dust in the shed. I used to commute to campus on this thing everyday and thought it would be fun to fix it up. So I decided to get it running well again, and clean it up at the least. As time goes on I'll see how much more I wanna invest in the project.

So here it is as it sits in non-running dusty glory.

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Re: Batavus HS-50 fix up

Ziad Younis /

more photos

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Re: Batavus HS-50 fix up

Ziad Younis /

To start off, the motor turns over and receives fuel but won't fire up. Rather than diagnose the issue, I decided to jump right into an engine rebuild. It's long overdue anyways and this will give me a chance to learn more about the engine components, how they work, and the electrical system.

And that leaves me to where I am currently. I took the motor off the bike (fairly simple) and then realized I need a flywheel puller to completely disassemble the engine.

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I ordered the flywheel puller, some new engine studs, a gasket kit, and a new clutch plate that should be arriving thursday.

Re: Batavus HS-50 fix up

Andrew Squiggman /

Should just cleaned yer carb replaced lines and cleaned tank. You'd be riding now

Re: Batavus HS-50 fix up

Should grab yourself the cylinder kit and exhaust pipe off of Treatland.tv. I've heard good things about them.

Re: Batavus HS-50 fix up

Ziad Younis /

> Daniel '' Wrote:

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

> Should grab yourself the cylinder kit and exhaust pipe off of

> Treatland.tv. I've heard good things about them.

Yeah I was looking at those, kinda expensive but seems worth it.

Re: Batavus HS-50 fix up

Ziad Younis /

Got the stuff today. . . I nearly completely took apart the engine. Here it is below.

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After a quick inspection, I noticed scoring on the piston and a bit on the cylinder wall too.

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I have another piston I may try to salvage, and maybe clean out the cylinder at some point. Also have a bunch of other stuff including an m56 cylinder and head that I might be able to use with a makeshift adapter plate I made in college machine shop. Treatland offered the adapter plate at one point but sold out.

The bearings,crank case, and crankshaft all look fine but need some cleaning and grease, so I'll do that next and reassemble with a new gasket.

Cheers !

Re: Batavus HS-50 fix up

That piston and cylinder really don't look all that bad . Unless tolerances are way out ,

I'd clean those and run 'em , if you're going to stay stockish .

Re: Batavus HS-50 fix up

> P D Wrote:

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

> That piston and cylinder really don't look all that bad . Unless

> tolerances are way out ,

That piston is toast, can't really see the inside of the cilinder but even in a blurry pic you can see scoring.

If you have 0$ to spend then yeah run it, otherwise just chuck it. (edited)

Re: Batavus HS-50 fix up

Jeez yah there is no way i'd run that piston, that thing is TOAST man.

Hey i made those m56 adapters, i made 20 of them back in 2011 and they took like 5 years to sell, haha. not really worth doing another production run since i think i was only getting like $5 each for them, and i had to buy a huge sheet of an odd thickness of aluminum.

i still have the very last one, i just found it when i moved and was digging through some boxes. if you want it send me a PM.

the m56 swap takes a bit of screwing around, the exhaust is way different so you gotta figure that out, but it runs really well. not ported/stock pipe i was well over 30.

Re: Batavus HS-50 fix up

Toast ???

Meh . I've run pistons that look a lot worse than that one and they ran for a long time .

But , if you have money than you'll ever need , sure new is sometimes better , but , not always .

Re: Batavus HS-50 fix up

Ziad Younis /

@ P D I'd have to agree with the other guys man, it looks bad. I'm not saying the engine won't run, but since I've got the engine apart I might as well put nice clean parts back together to run superb.

@Graham, I'll probably take you up on that offer. I've been wanting to throw the m56 on for forever but never got the fitting right. I know I'll have to bend the header to fit the m48 mounting position, maybe I'll use sand or something and go to town.

Re: Batavus HS-50 fix up

Ziad Younis /

So today I cleaned the crankcase with engine de-greaser and a plastic wire brush. I finished it off with carburetor cleaner to remove all the loose dirt. the bearings were in great shape, so I cleaned out with throttle body cleaner and then added 2-stroke oil to lubricate. After doing that I put the crankcase back together with the new gasket. (the crankshaft had to be hammered into place on the clutch side) Disclaimer- be careful doing this, as I apparently damaged the top threads on the flywheel side and had to cut new ones using an m10-1.0 die.

Then. . . the magneto was reinstalled and the flywheel secured with an impact gun.

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On the clutch side. . . I applied some anti-seize to the spring and balls. and put back together with the new clutch pad.

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Re: Batavus HS-50 fix up

Never hammer on threads!! You should have used heat on the bearings and frozen the crankshaft. Everything slips together smooth. If you have to hammer its best to use a dead blow or a hard rubber mallet.

Re: Batavus HS-50 fix up

Ziad Younis /

Clutch side and flywheel side finished!

One of the threaded stud bosses in the crankcase was stripped so I re-tapped using an m6-1.0 tap. It went in securely after that (bottom right in the pic below).

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In an attempt to save some dough, and maybe effort as well. . . I won't go with the motomatic kit just yet. If I can get Graham's adapter plate I'll try the m56 cylinder and head first. Next step is to clean the carb and get new nuts for the head studs, the old ones are toast.

Re: Batavus HS-50 fix up

Ziad Younis /

> Daniel '' Wrote:

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

> Never hammer on threads!! You should have used heat on the bearings and

> frozen the crankshaft. Everything slips together smooth. If you have to

> hammer its best to use a dead blow or a hard rubber mallet.

Yup. Lesson learned

Re: Batavus HS-50 fix up

Brandon Weiss (Detective brandon to you) /

Anti seize in the transmission/clutch? That doesnt sound like a good idea to me.

Re: Batavus HS-50 fix up

Ziad Younis /

It's fine I've used it before. In this application it lubricates the ball and springs without making a mess or gunking up like other greases do. It doesn't cause abrasion either, since there isn't a high amount of movement within that clutch cavity. I wouldn't use it on a conventional ball or roller bearing, but in this case it works well.

> Brandon Weiss (Detective brandon to you) Wrote:

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

> Anti seize in the transmission/clutch? That doesnt sound like a good

> idea to me.

Re: Batavus HS-50 fix up

Yea it's totally recommended on the stock bat clutch

Re: Batavus HS-50 fix up

Brandon Weiss (Detective brandon to you) /

Welp, you learn somethin' new every day!

Re: Batavus HS-50 fix up

Ziad Younis /

Merry Christmas Post! I was away in Cali for a week, but I'm back at it.

So the adapter shim I made in college was too thin, that's why I never ran the m56 head. Recently, I received Graham's m48 to m56 shim in the mail and it's even thinner than the one I made in college. Below Graham's 3mm shim & my 4.8mm shim.

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Re: Batavus HS-50 fix up

Ziad Younis /

The good news is, I might be able to combine the two shims to get the proper piston clearance. I did a test fit with both shims and here's what I got.

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The top picture shows the piston clearing the exhaust port by a couple millimeters, and the bottom picture shows the piston barely clearing the intake ports. When stores open back up tomorrow, I'll buy some fellpro gasket material and make a gasket for the m56 block to give it another millimeter or so of clearance.

Either way, I'm limited with the tools I have, but I'll try to cut the edges on the adapters to clear the crankcase fuel tunnels.

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I also disassembled the encarwi 30mph carb, cleaned it with carb cleaner and reassembled. The float was readjusted to 11mm clearance from bottom tip and the current jet is size 56. This was really straight forward, so I didn't think this deserved any pictures.

Re: Batavus HS-50 fix up

Ziad Younis /

So I ran into a few issues during the holidays. . . but long story short is that it runs!

I let it idle and revved it up, it seemed to have great power and smooth delivery but I won't know until spring when I can actually ride it.

First of all here's a pic of the two shims and multiple gaskets. And the motor installed on the bike.

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When I got the motor back on the bike, I wasn't getting any spark. I ordered a new ignition coil, installed, still no spark. Then I took apart the run/off switch on the handlebars, put it back together and voila! Maybe it was grounding itself? who knows?

My other issue was fuel delivery. Kinda like the rappers of today, my petcock had no flow. It was gunked up from sitting for nearly 2 years. I ordered a new OMG petcock from treats and now I have too much flow! JK! but there is an issue with fuel leaking from the carburetor. I'll cut a new fuel bowl gasket and check that the float is adjusted and working properly.

After doing that stuff, I'll move onto cosmetics, brakes, cables, etc. until spring rolls around. I also need to fab up the pipe so that I can get a muffler on the bike without dragging. I'm thinking about cutting it, grinding down to the correct angle and re-welding.

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Re: Batavus HS-50 fix up

Great progress! Surely you could heat that header, slip something in there and bend it to get the angle? Saves cutting and welding.

Re: Batavus HS-50 fix up

Pushrod Fifty /

Piston arrow should face exhaust port?

Re: Batavus HS-50 fix up

> John Maxson Wrote:

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

> Piston arrow should face exhaust port?

I've never seen it otherwise . ;)

Re: Batavus HS-50 fix up

i actually like the use of the term "fuel tunnels" it has a good visual to it.

Re: Batavus HS-50 fix up

Tri-ped Dave O.D.B. /

On the clutch, open up the spring and replace every other steel ball with identical size aluminum ball bearings. Instead of grabbing at 700 rpm bogging miserably as Bats are well known to do, it will grab at 1200-1400 rpm giving you far better pick up. As long as you are doing all this work, you may as well improve on it more.

Unapproved Message (moderated by simon)

Re: Batavus HS-50 fix up

Cool !

Re: Batavus HS-50 fix up

Ziad Younis /

> Ryan Graeme Wrote:

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

> Great progress! Surely you could heat that header, slip something in

> there and bend it to get the angle? Saves cutting and welding.

Thanks! I'm worried about crimping it because the angle is pretty large.

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