"Project Bantam" - Arts and Crafts

I've finally amassed all the parts required for the Briggs&Stratton 14FB engine overhaul.  The main bearings look good, and the piston ring gaps are within spec using new standard size rings.  One of the exhaust valve keepers was rattling around in the tappet chamber when I opened the tappet cover last month.  The exhaust valve seat was rather rusted and required significant lapping to get down to good metal.  A quick grind on the valve stems put it back within gap specification.

exhaust = 0.015"

intake = 0.008"

The gudgeon pin is still tight and the piston looks good as well.  It can be put back in with the new standard size rings.

I went with a two-tone paint job on the block.  The fins were rather rusted, so I wanted to make sure they got painted and stayed painted.  So they got a 1200'F rated exhaust paint in silver.  The crankcase got a 500'F rated engine paint in black.  The exhaust elbow was rusted fast, but the threaded adapter to the exhaust pipe still had good threads, so that's staying.  I just need to obtain a new mating nut and olive for the exhaust.  It looks like an electrical fitting.

I had my son help with the arts and crafts.  Making measurements and cutting gaskets is a tedious task, but still enjoyable.  I started with some relatively thick gasket material for the tappet cover, point cover, and oil pan.  The bearing housings require some adjustment based on axial float of the crankshaft.  I made them out of thin material as templates.  I can go back and duplicate these easily when I get the crank set in, if the float needs increased to meet spec in the manual.

On closer inspection there are marks on the inside of the timing gears.  It looks like someone has had this engine apart before, since the cam gear has a awl scratch on it pointing to the correct place between the timing teeth.  The manual says to set the timing based on the outside of the gears, which is presently obstructed by the main bearing.  Timing will have to be set by the inside viewing through the bottom of the crankcase.

S7 Clutch Release Bearing Mod

The VXB 6x14x5mm Miniature Thrust Bearings arrived today and were easily installed in place of the original balls.  I added some moly grease for extra insurance.  The height gain was only a few thousandths from the worn parts, and easily allowed the clip ring to be replaced with room to spare.

Clutch Release Bearing Worry.

I've been getting an annoying clunk when shifting gears on KYL95.  I adjusted the clutch cold, but when hot it seems not to disengage properly.  Consulting the SOF gurus and Sept/October 2010 issue of On the Beam, I discovered that a modern bearing AKL 6 could be placed between the original release bearing races and maintain the original configuration.  Brilliant, except that I couldn't find that model number locally.

Off to trusty eBay with no results.  So I got the dimensions (6 x 14 x 5mm) and went searching further to discover VXB Bearing selling through Amazon.
http://www.amazon.com/Thrust-Bearing-6x14x5-Miniature-Bearings/dp/B002BBKCAE/ref=sr_1_1?ie=UTF8&qid=1336961575&sr=8-1

They might actually be delivered in two days!

Luckily the clutch release bearing can be removed easily without dismantling the bike.  Pulling it out revealed that there's nothing really wrong with it, except some radial wear inside the bearing holder cup.  Since there really isn't supposed to be any radial load, and I can probably attribute that to some numbskull in the past putting a frapping nail in place of the clutch push rod.

 

The release bearing is easily removed.  Notice my clever Viton o-ring seal "glued" to the outside lip of the gearbox.

 

The locknut is knocked loose, then removed, after that the bolt can be removed. 

 The balls look fine.  There's a little wear on the races, but nowhere near anything catastrophic.  With nothing to keep the balls evenly spaced, I'm sure they're bumping into one another, shifting the load on the races.

 

The whole assembly fits together like this and then drops down into the cup.

 

Sorry for the blurry picture, but the wear inside the cup is evident from some radial load on the bearing.

The next installment will be investigating the installation of the new bearing.

Imp Water Pump

I had a terrible time previously obtaining an Imp Water Pump rebuild Kit through US customs the last time.  This time I was determined to obtain the correct parts locally.

The bearings turned out to be a double-sealed variety which are fairly common.
6202 2RS Double Sealed Bearing 15mm x 35mm x 11mm

The seals were a little harder to find, but a tip from a friend led me to look at pool pump suppliers for an AVON type B seal:
16B36

All is back together and working fine.