A Guide to Bicycle Motor Preparation And Care

These engines were originally made to haul people around for a tiny sip of fuel, low operating costs, and ease of MAINTENANCE- understand I don't mean NO MAINTENANCE....kinda like the old V-Dub beetle. Or the early Honda step through. Or the model T.

Top performance for these engines then should be defined as great fuel mileage, ease of operation and low overall cost.

Some are treating these engines like they should do something other than putt around on a small amount of fuel all day and get you where you are going with a minimum of drama. You CAN make them put out more power, but you'll pay the price in longevity and reliability.

You aren't going to make one of these engines haul you down the coast @ 45+ MPH or win any stop light drags with that blue haired lady in the Volvo. (although, you may)

You aren't going to find any magic fuel or "performance" add-on that is going to do anything you can't do for pretty much free with the exception being your time. Coleman fuel? nah...super duper spark plug thingy? nah....NOS or turbos? Are you serious? You aren't really serious, are you?

100+ MPG? Yes. Easy running, and easy maintenance? Yes. Lots of tinkering and learning to do maintenance and repairs? Yes, if you want to keep riding it. Fun? Of course, why else would you want to own one?

First off, I know the "instructions" say to break the engine in at 16:1....don't do it. 24:1 is more than sufficient. The reason the "instructions" say to use 16:1 is they use 30 weight motor oil in China, or did when these were first designed.
Many have successfully run 50:1. I would start at 24:1 and go to 24:1 or 32:1 after break in.

Buy a good plug, and a good replacement 7mm spark plug wire and cap from Pep Boys or other favorite large auto outlet.

Never remove a spark plug from a hot engine, you may remove the threads from the head as well.
Here's a list of replacement plugs- do it today!

NGK B5HS, B6HS, or B7HS
Champion L86C
Autolite 4093 or 425
Gap it at .025"-.028"

While we're on the subject of sparks- remove or replace the kill switch, they are junk. Buy a new one at Radio Shack or other electronic supply store.



Buy some good gasket paper DON'T MAKE ONE FROM A CEREAL BOX! Gasket paper is cheap. Make a couple intake gaskets, and install one, with a thin film of silicone sealer on both side even if you think yours is fine. You can make gaskets really easily by drawing the new gasket by using the old gasket as a pattern, and no, it doesn't have to be PERFECT. Use an exacto knife and take your time, finish the rough stuff with some 220 sandpaper. Some of you (me) old-timers will use the "good old ball peen hammer method" to make the gaskets. Carve out the exhaust gasket to more closely match the exhaust port. This will open up the exhaust a little, and also will help prevent gasket blow outs here.

Make sure your carb is set right and that means check where the needle clip is, start at the second from the top in most cases. One slot lower near sea level. I have two bikes and they are both set up differently due to poor tolerances in manufacturing FIND THE ONE THAT WORKS FOR YOU- it just depends on your carb and your elevation. (I'm @ 1000' here) Check your plug, it should be brown to black. Move the "C" clip up a notch if it is too black and oily. Move it down a notch if you find the plug is grey or white.

FYI- Despite what a lot of the "instructions" say, the screw on the carb is NOT for mixture...it's just an idle speed screw. Turn it in (clockwise) for a higher idle speed.

Clean out your tank before you mount it...at least look in there and see if it's full of rust or crud. You can use a shop vac ONLY IF THERE HAS NEVER BEEN ONE DROP OF FUEL IN IT...otherwise you'll blow your shop vac, and maybe your garage and self to smithereens.

While your in a cleaning mood, pop off the mag side cover(s) and clean all the metal shavings out of there with some spray brake cleaner and compressed air. Check the area around the sprocket too- full of metal dust!
While you have this cover off, take a good look behind the magneto flywheel- there is a seal behind it, and if it is not properly seated, do that with a smooth wooden hammer handle or dowel, not a screw driver. Just gently push it in evenly all the way around.

To save yourself a lot of hassle, buy a length of M6X1.00 pitch threaded rod and BE READY TO REPLACE ALL THE STUDS. Or use bolts like I did. Those would be the intake, exhaust and also the four mounting studs. The originals will strip at the first inopportune moment.

Secure all wires with zip ties or electricians tape so none are pulling at the ends or connections. Seal up any ends/connections that are in doubt with liquid electricians tape...READ THE DIRECTIONS ON THE CAN!

Grease your gears with some wheel bearing grease or lithium grease before you ever fire the engine up, then again after about 50 miles. USE ONLY A TINY AMOUNT OR YOU'LL BE CLEANING THE CLUTCH SOON. (a dab about the size of a dime is PLENTY) Clean them first with some brake cleaner, or carb cleaner, then lube. Spread the grease around on the teeth of the large gear, again, you don't need much.
Don't spray brake or carb cleaner in your eyes, you won't be doing anything else on the bike for awhile afterwards, if ever.

While you are greasing stuff remove, clean and grease all your wheel bearings, or YOU WILL BE SORRY. Bicycles are not really made to haul a 200+ pound guy over the road and all the bumps/potholes/ect @ 25-35 mph. The bearings take a massive beating. Use red grease because it starts to turn black when it needs servicing.

Make sure your chain is aligned and lubed. Same goes for the pulley/tensioner. Don't make the chain TOO TIGHT. 3/4-1" play.
Always clip on your masterlink so the opened end faces toward the rear when it's at the top of the chain run and going forward. The chain is good for a few thousand miles but can be replaced with #41 when the time comes.

Zip tie/cable tie your spokes where they cross while you are installing your sprocket, this will firm up the wheel and help keep spokes from breaking.

Balance your wheels- I used solder wrapped around the spokes at the rim. You can buy stick on weights at the sporting goods store...in the golf aisle. You'd be surprised at how much those reflectors weigh! I removed the reflectors and then balanced the wheels, leaving the reflectors off.

Don't try to use your clutch to take off, at least give the bike a good shove. Those of us (you know who you are) that are pushing 200 pounds need to pedal a bit then release the clutch...the exercise won't kill ya'!

Use Loctite or at least nail polish on every bolt you put a wrench on, and don't OVERTIGHTEN the head bolts, or any bolt that goes into aluminum- 10-15 ft/lbs. is enough, and that goes for the spark plug too! While we're on the subject, you do use anti-seize compound on the plug threads, don't you? Never remove a sparkplug from a hot engine, you may remove the threads from the head as well.

Some have suggested that Loctite is not a good thing....I have used it on all kinds of products for years and years and if you use the right stuff, applied properly, it's great. Those who fear Loctite can always double nut everything...then watch the first nut vibrate off about 20 minutes before the second one does.

Make sure your brakes are up to par. Stuff hurts more @ 35MPH than it does @ 10MPH, especially if it stops you before your brakes do.

Ride defensively, because the only drivers that will see you are the ones you DON'T want to see you- aka "da fuzz".

Wear all the protective gear you care to wear, eye protection at the very least, helmet/knee/elbow pads are good. If you've ever had road rash, you'll cover up with SOMETHING.

If you have a problem with dogs chasing you- mostly ignore them and ride on by, you usually get into trouble when you are watching the dogs and not the road....kicking and screaming at them doesn't help either.