Honda Spree and Elite 50 Forums

This is a Winter build project that's been ongoing in the Meatball garage. 49cc's is fun but it would be double the fun with 98cc's! A 50x50 stroker beginning with a bare bones AF16 block. First order of business is to clean the motor completely.

Remove/replace all trans bearings and oil seals. I had to cobble together some makeshift bearing pullers since a few of them cant be pulled with a typical puller.

The case was cut to fit the 50mm stroke crank. It also had the intake windows, boost port and a couple other key spots opened up. Crank fits nicely.

First pic is of the untouched boost port with a Corsa base gasket. Next pic shows it with the stroker bore's base gasket with port work.

This will have a ZX trans so more cutting is needed. Grind out a couple bumps around the clutch area and belt travel zone. It might be too much but its better than not enough and shred belts.

This will have either a Polini or Malossi for Ruckus variator so more grinding needs to happen. The Dremel gets another workout.

Now that grind work is done, case was cleaned of all shavings and prepped for assembly. Starting with trans bearing install. Freezing them overnight and heating up the case with a torch makes install a snap. They dont exactly fall in but just a few light taps to get them seated. Finding an OEM Honda 6202 bearing isnt easy. All others are readily available everywhere but that one. I gave up and went with a quality Taiwan replacement.

Crank bearings went in easy with the freeze/heat/tap method. Also squeezed in new motor mount bushings for good measure.

Test fitting the oil pump plug and sealing it from the inside with JB Weld. I did this before crank bearings went in. You can see a bit of the intake window opened up. I shouldve taken more pics but I was "in the zone" and forgot to stop and snap a few. This post is out of sequence.

Pulling the crank is too easy with the TUSK tool. Almost like cheating. To seal up the case I used Yamabond. You'd be surprised how many Honda shops use this stuff over Hondabond.

Now that the PG full-circle 50mm stroke crank is installed and the case is sealed up, I move onto the 50mm bore. I went with a PG for that as well. They make good quality products but some prep work should be done before install. Time to bust out the Dremel again!

Taking a tiny jeweler's file I carefully chamferred the ports to remove the sharp edges. Its not much but enough to knock down the razor-like edges to let the rings happily slide by.

The exhaust port had rather large casting flaws so it needed to be sanded down smooth. Then I polished it to a mirror finish to allow better flow of exhaust gasses and to reduce carbon build-up.

Chamferring the edges around the transfer area also help. Pic shows mid-process. The final outcome looked much cleaner.

After all the grinding on the bore, it was fully cleaned of all shavings and oiled. Now I can check the ring end gap. Surprisingly, one ring was within spec but the other was too tight and needed a couple passes on a file.