Tuesday, April 2, 2013

My 1979 Puch Magnum MKII Moped Restoration: The Trials and Tribulations


   Well i've got a $1,000 piece of 1979 Austrian metal in my house. My goal is simply to get it running, rolling, and stopping. It's current setup is a 64cc Polini racing kit, port matched to a freshly rebuilt, re-pucked ZA50 2 speed engine, new 15mm genuine Bing carb, and a MLM Magnum Cali exhaust pipe, and brand new tires- Michelin M62 Gazelles. Other aesthetic mods I will address later, like cafe handlebars, LED lights, reupholstered seat, digital speedometer and head temp gauge, etc. Yesterday I started the conversion from loose, obsolete wheel bearings to modern, superior sealed bearings. After a long, perilous journey the rear bearings finally arrived from England. The stronger 12mm axles (replacing the original 10mm axles) and front bearings from moped superstore (and magnum freaks) www.Treatland.tv, printed out This great tutorial and finally got to work.
   Knocking out the old bearings was actually fun as i didn't have to worry about ruining them, although this step was very messy. Grease plopped everywhere. I suggest wearing disposable gloves and work clothes you dont mind ruining. Also, clean up and save your old Puch axles and bearing cups, etc, as you never know when you or someone on the forums might need them. Once i had everything degreased i sanded all the rust off the wheel hubs so the new breaks have some metal to grab. I was pleased with how well they cleaned up with just 100 grit, then 220  aluminum sandpaper. Who knew there was shiny metal under all that orange stuff?
   I squeezed a little blue loctite onto one side of the front hub and using a rubber mallet and an axle with a nut on the end I carefully tapped the shiny new sealed-bearing flush with the wheel.
Strangely, the bearing was the rubber sided kind, while i thought i ordered the metal sided, but its no biggie, although one apparently handles higher rpms's better, while one keeps rain and gunk out better. The tutorial was a bit unclear about which one did which. So be sure to double check which bearings you are ordering before if its important to you.
So i cut a spacer from 12mm ID pipe and stuck it on the axle so it will keep the bearing in place so the middle parts don't cave in into the hub. Then i loctited the brake side and popped the last bearing in the same way as the first. It wasn't perfectly flush, and sticks out about 1-2mm, which i hope isn't a big issue because i really don't want to have to get them back out.
I had to drill the brake plates to open them up for the new, beefier 12mm axles. The little black rubber grommets in the brake-lining-check holes I found at Ace's today, they are actually some kind of toilet gasket and i had to pull out a harder piece that sat inside them. The old grommets had dried up so much that one actually just fell out and the other rattle like they were contemplating similar fates.

I eventually got this set flush, and with spacer cut to exact specs this time. Had to finally grab the steel hammer to get it budge and be flush. 
 
 I then carefully, slowly drilled out the brake plate hole using a 12mm metal drill bit and a cordless drill, with the brake plate clamped onto the work bench. The bit kept binding up until i learned to go very, very slowly with the drill at full speed ( chuck set to "drill" setting, too, don't forget).
   Lastly, I used a bunch of 12mm inner diameter washers to space the break plate out far enough to where it wont bind up on the hub. Then i was done for the night. Until i remembered i was going to bend my bent pedal crank back straight. So I stuck it in my bench vise, stuck an old heavy piece of about 4 foot long lead pipe i found out back over the crank arm and slowly, pulling from the very end,gradually straightened it back out, and even bent it a little farther out to ensure it won't hit my new $280 MLM Cali exhaust pipe.
Then, feeling tired yet pleased from the evenings progress, I retired with a cold beer. ( Apocolypse IPA from 10 Barrel Brewing in Bend, Oregon. This is a favorite of me and my Dad's and a friend of his, just back from Portland, had kindly dropped some off that night, and i was hoping it was properly chilled by now. It's not available anywhere in Spokane that we know of, so we always try to bring some back from Oregon Country whenever we are down there, and this time my Dad must've enlisted even his friends in the endeavor to find and drink the worlds best IPA.)
While i had the wheels apart I also replaced the old rusted asbestos brakes with new non-asbestos high quality EBC brakes. These were not easy to find. Treats and 1977mopeds were both out and i was unable to obtain them direct from EBC. Also, incredibly, no other source was available that i could find so i had to wait for them to come back in stock and treats got em first so i bought them as soon as i got their item-back-in-stock email notice. Good breaks are even more important when your moped will potentially hit 60mph, not the stock 30.

New sealed bearings set flush in rear freewheel side. 

Say goodbye to your speedo cable. I could find no way to install the stock speedometer thingy after the sealed bearing conversion. I am planning on purchasing a good iphone handlebar mount bracket, or making my own, and using a gps based speedometer. This will be nice for using google maps when cruising around, and a nice bright screen. Hooking it up to power would be another goal, so it will recharge as i'm cruising around.