This is a page that chronicles my little dabblings in the workshop.
The photo's below show, if not anything else what a bit of scrounging and imagination can achieve, a Whipper Snipper powered bike. I don't know if it will work out but check out the progress over the coming weeks.
I really wanted a bike with a 24" frame with the old style peddle brake, i.e. no gears. I found it was nearly impossible to find a bike of that configuration with a 24" frame. I contacted a couple of local bike shops and made enquires about purchasing a rear brake wheel, the answer, they don't make "em" anymore. After a trip to the local tip the above bike was found, not the size I was really after but it does have all the features I require.
This is 18cc of raw power originally used on a Whipper Snipper that was cactus. A complete strip down, clean up, replace all seals and it goes like a train.
An adaptor pattern knocked up for mounting the power plant to the bike
The finished casting ready to machine and mount the support bearing in
The kids should love this little number, just got to convince mum it's safe.
What the show looks like. The housing has been bored out and a bearing fitted to support the new drive shaft. The drive roller which is in contact with the wheel is pushed on and keyed to the drive shaft.
View showing how the motor is mounted to the bike. I've used a couple of Stauff clamps to secure the bracket to the bike which supports the pivot assembly.
Remember I said something about convincing my wife it was perfectly safe for the kids. It just got a little harder.
With a lot of skin off the palms of my hands, I won't be in the workshop for a while. I've had a lecture from my good wife about the safety aspects of what I'm doing. No come back to that one, I'll just put my tail between my legs and quietly agree that maybe she just might have a point. Trying to sleep tonight will be difficult so I'll just ponder on her words of wisdom while I try to get comfortable.
Anyway the Whipper Snipper bike goes like a rocket. I estimate top speed around 30 Km/h. Starting is simple, just peddle hit the throttle and most importantly hang on. There will have to be some adjustments made before the kids can have a crack at it.
A young man as happy as Larry.
Well things didn't last as long as I thought they would. The trouble started when my eldest son bought the bike home with the engine still running but no drive from the output shaft.
Well after stripping down it was found the main crank drive shaft had sheared in half. After paying a visit to every mower repair place in the city with no joy of finding a replacement it was decided to repair the whole show and make sure it didn't happen again.
The keyway locations for the magneto wheel where marked on the crank bell using a height gauge. The crank shaft was then clocked true in the lathe, and then cut off. The crank was bored out ready for the new improved shaft. The new shaft is a one piece affair out of EN25 unlike the old one which was SG cast iron and adaptors had to be made up to retro fit it to the drive hub. A full length 3/16" keyway was cut prior to press fitting and Loc-titeing the shaft into the bell crank inline with the original keyway to ensure the timing was not affected. A 5/32" roll pin was Scotch keyed into the bell crank and new crank shaft to ensure there is no movement during operation. The magneto wheel was bored to suit the new shaft and new 3/16" keyway cut in the same location as the original.
A set of new bearings and seals (again) and the whole things back together. I've only just bench tested it. It fired and ran, now I've just got to machine up the new drive hub along with a support spacer and it can be fitted back into the housing mounted on the bike.