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Instructions for Building and Repairing Motorized Bicycle Engine Kits Classic posts on building, repairing and modifications.

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Old 01-15-2008, 10:22 AM
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deacon deacon is offline
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Default motorized bicycle quick tips

You know most of us do things eventually to modify the bikes for the better or worse. It would be a nice gesture if we stick them out there for others to see.

Take this one for what it is worth.

The clutch lever in my kit was trash from the first. I never could make it work worth a darn, so I replaced it with a brake lever I had laying about. Here is the trick. I cut a piece of old inner tube to lock the handle up so I could roll the bike in and out. I leave it on the grip so I can use it to hold the clutch in if I need to adjust the bike.

I also hated the throttle that came with the bike. I replace it with a shifter from a mountain bike. I can lock the throttle in any position while I work on things. I don't think either of those is earth shattering, but they seem to work better for me. Probably won't help anyone else.

So leave me your tip I can use all the help I can get...
Old 01-15-2008, 01:19 PM
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Default Re: take a tip...leave a tip

My tip: In the formation stage - As received my kit gas tank has "stuff" in it (chunks, rust, dirt). Supposedly the carb and petcock have screens in them (according to eBay kit seller)....but they must be invisible. So on the way home today, I'm buying an inline see through fuel filter at the auto parts store. SHOULD work like a champ.
Old 01-15-2008, 02:30 PM
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Default Re: take a tip...leave a tip

Originally Posted by deacon View Post
Mine came in pretty good I think, but I wish now I had washed the tank out with gas BEFORE I installed the petcock. Whatever was in there is in there now. I did take it out actually to check the filter. I wanted to make sure that the darn thing was clogged since gas trickles from the tank most of the time.

That seems to be normal for that system. Trickling like a man with an enlarged prostate
So maybe this leads to my tip #2: When I took my tank out of the box, it rattled with all the junk in there. So I've blown it out with compressed air really well while shaking, etc and the rattling stopped. Now I have it sitting with a bunch PB Blaster blown in to halt any oxidation. When it comes time to mount it, I'll rinse with some of last year's premix.
Old 01-15-2008, 03:04 PM
Bikeguy Joe Bikeguy Joe is offline
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Default take a tip...leave a tip...or a bunch of 'em

These engines were originally made to haul around people for a tiny sip of fuel, low operating costs, and ease of 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 litre of fuel all day and get you where you are going with a minimum of drama.

You aren't going to make one of these engines haul you down the coast @ 40+ 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 maintenence and repairs? Yes, if you want to keep riding it. Fun? Of course, why else would you want to own one?

Buy a good plug, and a good replacement sparkplug wire cap from Pep Boys or other favorite large auto outlet.
Never remove a sparkplug 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 (preferred)
Champion L86C
Champion CJ7Y low profile or CJ-8
Autolite 4093 or 425

Mix your fuel/oil mixture @ 20:1 for break-in and 36:1 after.

Buy some good gasket paper DON'T MAKE ONE FROM A CEREAL BOx! (really cheap) and make a couple intake gaskets, and install one, 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.

Make sure your carb is set right and that means check where the needle clip is, start at the second from the bottom in most cases. One slot lower near sea level. I have two bikes and they are both set up diferently 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)

Clean out your tank before you mount 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...otherwise you'll blow your shop vac to smithereens.

While your in a cleaning mood, pop off the mag side cover and clean all the metal shavings out of there with some spray can brake cleaner and compressed air. Check the area around the sprocket too- full of metal dust!

To save yourself a lot of hassle, buy a length of M6X1.00 pitch threaded rod and REPLACE ALL THE STUDS. Or make them outta bolts like I did. Those would be the intake, exhaust and also the four mounting studs. The originals are made of "anti-metal" and 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 pencil eraser is PLENTY. Clean them first with some brake cleaner, or carb cleaner, then lube.
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.

Zip tie your spokes where they cross while you are installing your sprocket.

Balance your wheels- I used solder wrapped around the spokes at the rim.

Don't try to use your clutch to take off.

Use loctite on every bolt you put a wrench on, and don't OVERTIGHTEN the head bolts, or any bolt that goes into aluminum. 15-20 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.

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".

If you have a problem with dogs chasing you- eventually they get old and bored and leave you alone...if they are smart.
Old 01-16-2008, 05:31 PM
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deacon deacon is offline
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Default Re: take a tip...leave a tip

since we are sharing tips.... this probably isn't for everyone but...

I bought a 20" kids bike for the wheels to make a trailer. At the same time I was having trouble with one of my big bikes. The pedals were just to high on the upstroke. It was very uncomfortable and it was my first bike in forty years so I was still relearning how to do things. My balance was terrible at the time and the discomfort was worrisome.

Anyway, I switched out the crank and pedal sets. Low and behold the pedals were low enough to actually be comfortable. Yes I had to shorten the chain a few links but it gave me a great big unexpected advantage as well. I put this on on electric bike at first and it make the hills easier to climb. I had a smaller front gear so it pedaled easier. I moved that crank set to my 24 kit bike now. Today I realize that it makes starting off from a stop sign on a hill a heck of a lot easier. Since all I really use the pedals for is to start off and to assist on steep hills right now, the smaller sprocket makes no difference and the pedal throw is much more comfortable.

Like I said not for everyone but it might be something to think about if you have a kids bike around. Might only work on cruisers though.
Old 01-16-2008, 05:46 PM
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Andyinchville1 Andyinchville1 is offline
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Default Re: take a tip...leave a tip

On some of the new engine kits I have installed there has been junk in the gas tank right from the factory....yes a shop vac can suck out loose stuff (obviously, as mentioned earlier, only do this BEFORE any gas has been used).

I typically go a step further though....I assume there may be loose stuff waiting to break loose so I will put some bb's ( or larger sling shot bearings) into the new tank and shake for awhile....You'd surprised how well this cleans up even surface rust in the tank...of course you have to thoroughly vac / clean out the tank afterwards....You can rest assured that there is nothing waiting to break free and plug up the in tank strainer.


Old 01-16-2008, 08:54 PM
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Norman Norman is offline
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Default Re: take a tip...leave a tip

to clean your tank if new and if used make sure its emptenty and buy a box of bb's or pellets or lead or steel shot washer etc. something metalic easy in to be easy out pour into tank. Shake the tank with the cap on and fueline plugged until your arms feel like they are going to fall off.or the redneck way I do not recommend this way warp it in towels and throw it in the dryer this is a good way to see God because if you've ever had gas in there you and eveyone there will see him or the other guy.BOOOOOM!
Now that we are tired of shaking the tank rince it with warm soapy water and rince with clean water then get a bottle of heat and rince the tank with it . You should be good to go rust should be mostly gone you could spary B-12 carb cleaner in there or wd-40 until your ready to put in fuel and please use an inline fuel filter.
Old 01-16-2008, 11:13 PM
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MotorbikeMike MotorbikeMike is offline
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Default Re: take a tip...leave a tip

Tank cleaning: you guys go to a lot of trouble here, so I'll add to the mix with what I've been doing too long to remember.

Buy BB's or other tiny stuff? Nope! I will either use nuts and bolts, or a short lenght of small chain, chain is best as you only got to pull out one piece and you get it all.

Swish till done, and then I will swish with a bit of rubbing alcohol. Alcohol is cheap, easy and clean, and rarely ever explodes.

I hope this makes it easier for you-all!

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Old 01-18-2008, 05:52 PM
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iRide Customs iRide Customs is offline
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Default Re: take a tip...leave a tip

The best thing I have found is slipping rubber pieces between the cylinder fins. You will be blown away by the dramatic change in engine's unbelievable!!! Put them every where you can that does not restrict air flow.

Live life like you mean it...RIDE!!

Old 01-18-2008, 09:44 PM
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Pablo Pablo is offline
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Default Re: take a tip...leave a tip

Seems like the rubber will melt, but I know they actually sell dampers for that purpose. What rubber did you use?

Here's mine for today: I find that an 3/8" air ratchet is the cat's meow for the sprocket bolts. (a big air wrench is too bulky, ratchet nice!)

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