Zündapp type 249-02 engine build

Bought this engine from German eBay. Planning on doing this as right as I possibly can. Looking for tips and suggestions as far as cleaning and re sealing everything properly.

1384F66B-3C52-41D6-89A0-13189F0FF007.jpeg

Re: Zündapp type 249-02 engine build

Ian MacKenzie /

Is there a cleaning agent I can use to clean the case up and the barrel and head? The head sorta reminds me of a puch racing head in the fin design

Re: Zündapp type 249-02 engine build

daan SJAARLOOS /

Beadblasting or looooots of elbow grease with the cleaning agent of your choice

Re: Zündapp type 249-02 engine build

Ian MacKenzie /

Is there a big difference between bead blasting and fine glass blasting?

Re: Zündapp type 249-02 engine build

Vapor honing is the best. Will make it look new

Re: Zündapp type 249-02 engine build

> Satan 666 wrote:

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

> Vapor honing is the best. Will make it look new

That^ . Better finish .

Re: Zündapp type 249-02 engine build

Ian MacKenzie /

Ended up trying over cleaner on the Zündapp engine after sticking different parts in the old toaster oven. Baked them at 200°F then soaked them in the stuff.

879A026E-7882-4441-9E8B-7DF39F67B98E.jpeg

Let them soak for ten minutes then have them a quick scrub and wash in water. Think they turned out okay. Debating on coating the exterior of the engine. Not fully sure what with yet.

23B80DCC-6A21-4130-902F-A38EFD9B36E7.jpeg

Re: Zündapp type 249-02 engine build

I normally coat ali with ACF50 and rub it all in with a scotch pad, won't hold on the hot bits tho.

Word of warning on the oven cleaner, some are highly corrosive on ali. Friend of mine put some toilet floor board runners in a bag overnight, they came out really pitted and looking like they'd had a hard 50yr life, luckily that's the look he was aiming for. (edited)

Re: Zündapp type 249-02 engine build

Ian MacKenzie /

Ah thanks for the word of caution!

Luckily I read the back of the oven cleaner I bought to make sure it was safe! Would have had a real bad time if I hadn’t.

Re: Zündapp type 249-02 engine build

Jesse Nordlander /

Oven cleaner is usually sodium hydroxide. Great for degreasing but, it does eat aluminum.

Re: Zündapp type 249-02 engine build

Ian MacKenzie /

So I ended up spending a bit of the morning porting the clyinder to see if I can improve on it at all. Didn’t go crazy as I don’t have a full port map of the engine made up. However I do believe the little I did will do more good then harm.

I also ended up taking a old Jawa 210 exhaust pipe I had laying around. And after widening the flange mount holes I used a cut off wheel and cut it to the right length for my circuit pipe I bought as a hack and weld special off treatland. Looks pretty good if I say so myself.

09CD59E5-B0F9-472C-AAAB-FA1B067403B5.jpeg

Re: Zündapp type 249-02 engine build

What porting did you do?

Re: Zündapp type 249-02 engine build

Ian MacKenzie /

I ended up doing some mild porting. Widening the exhaust port a bit to make use of the performance pipe. I also widen and increased the intake timing port on the engine. I also made the intake from the carb flow into the casing better. Then added a little texture to the surface to increase atomizing of the fuel mixture. Not sure if it matters a terrible amount on that step when it comes to two strokes. But I know it helps on race car stuff.

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account