Motorized Bicycle Take a Tip...Leave a Tip

[Drewd]

Drill a hole for your throttle to ensure your throttle won't rotate. I pull the pin out of the throttle assembly and then drill a much smaller hole and then screw in a small machine screw. Never had any problem with doing this.

To help secure fuel tanks and chain tensioners, put double sided take on both. You'll never have to worry about either becoming loose after tightening them down.

 

[bigbutterbean]

Yeah, drilling a hole and putting a screw through the throttle might work. However, putting rubber in between the throttle and the handlebar has two advantages. One, it doesn't require drilling. Two, you can adjust the position of the throttle on the handlebar if you so desire. If you drill holes and mount it rigid, and later want to change the position, you have to drill another hole. The handlebars I have now are not drilled. All I did was put the strip of rubber on and tighten the screws, and it works great. No sliding. I can move it around any direction I want. As a matter of fact, I think I'm gonna go adjust it right now, because I don't like where my brake handle is at.

 

[Al.Fisherman]

Repairing a gas tank AFTER you put gas into it, using a torch

Remove as much fuel that you can, don't worry about all of it. Take a length of hose that will fit into the filler. Insert the other end into a exhaust pipe of a gas burner, making sure the exhaust will flow through the hose and into the tank. Let run until the gas tank gets as hot as the exhaust. Liquid gas will not burn, only the fumes. Once the tank is hot (about 10 minutes), let cool to handle it. Now you can braise, weld or whatever. When, back in the days of the dinosaurs, we had steel gas tanks...that is how we repaired them....I have never had a tank so much as go poof putting a flame to them. The CO2 from the exhaust kills the firing properties of gas.

 

[bigbutterbean]

Don't EVER use pliers or any other tool to tighten the cap on your carburetor barrel. It will take the barrel out of round and your throttle slide will get stuck in the barrel, leaving you stuck either at WOT or unable to accelerate at all. I currently have this problem, and the slide gets stuck at WOT. I have to try to straighten out the barrel in the morning. Hopefully it works. So, long story short, hand tighten only when attaching throttle to carb.

 

[MechEng]

When installing Manic Mechanic's sprocket hub adapter, put carbon fiber assembly gel between the hub and the adapter. The gel has a micro-aggregate in it which will increase the friction between the assembled parts, reducing the chance of slippage. It can be purchased, begged, or bartered from your friendly mechanics at your local independent bike shop.

 

[twelvestringtex]

I'm about half-way through the break-in period on my Grubee Skyhawk 2-stroker, and that first tank of gas pulled me about 50 miles despite fuel leaks, driving too fast, and inefficiencies of a new engine. One thing worth noting, it's really disappointing straight out of the box, and the first time you fire it up, but after that it just gets more fun every day!

Tips I've found...

#1)
Get a trunk rack, and trunk box. keep a vise-grip, socket set, bike tools, leftover bits of innertube, fuel line, chain, masterlinks, and thread locker. I've found it useful to carry around nearly enough tools to re-install the motor during the break-in period, just because so much of the assembly hasn't quite settled into place yet.

#2)
use that bit of inner-tube to make a gasket for any bicycle or motor components that try to slip around on the frame. Chain tensioner, Front derailleur, both engine brackets.

#3)
Replace the fuel line with something about 1/4" for a snugger fit, use hose clamps, and get some gasket sealer for the petcock. Teflon tape disintegrates.

 

[GearNut]

In reference to #2):
Putting any kind of rubber between the engine mounts and the frame tubing is asking for trouble. Yes, it will reduce the vibrations transferred to the frame by a little bit and may help with preventing the engine from slipping on the frame for a little while, but....and this is an important but.....it transferrs all the vibrations to the mounts and mount studs/ bolts. As the engine and it's mounts now shake and vibrate on the rubber it puts alot of additional stress on the hardware and will eventually lead to hardware failure.
Just do a search on "broken studs" to learn just how fun those are to deal with!

Ultimately an engine needs to be solidly mounted to the frame, and if there are any gaps in between the frame and mounts anywhere around the tubing, the mounts need to be filed or sanded to match up the curvature of them to the curvature of the frame tubing. A good tight fit means all the vibration is transferred to the frame which can handle it a heck of alot better than 4 teeny studs or bolts can. The mounts stay solid and secure, no shaking and vibrating to cause failure down the road.

 

[twelvestringtex]

That makes sense, the other thing that made me put those rubber gaskets in was to protect the frame, I had started to see aluminum flakes coming off where the motor was rubbing the frame. I guess that'd be solved by a better fit though. thanks!

 

[GearNut]

Custom fitting the mounts is the best way to go, but I will toss this out to you only as a last resort technique.
Some folks have had good luck with using liquid steel stick (generic name), which is like JB weld only it is a putty. Pack it into the mounts, put a single layer of plastic wrap around the frame tubing and install the engine. Scrape off the excess that squishes out and let the putty dry. Remove the engine to facilitate removal of the plastic wrap.
I cannot recommend doing it this way though unless you have no other alternative.
JB weld, or any kind of "steel" filler putty is just a fancy epoxy with the word steel in it's name. Epoxy is basically a form of plastic so if you do it this way keep an eye on it for cracking or separation from the metal you want it to stick to.

 

[uuu?]

hey

i just put my kit on and the Carburetor (New High Performance Gen B Carburetor from the GRUBEE 2010 SkyHawk GT5 66cc/80cc Angle Fire Slant Head Bicycle Engine Kit ) is leaking out of the filter on the back/red part.

i have never worked with a bike kit but i did put it together. it was running ok but it got a leak. it fluds with gas.

please help me, i dont know how to fix it and would like to know what to do before i try to fix it.

 

[GearNut]

hey

i just put my kit on and the Carburetor (New High Performance Gen B Carburetor from the GRUBEE 2010 SkyHawk GT5 66cc/80cc Angle Fire Slant Head Bicycle Engine Kit ) is leaking out of the filter on the back/red part.

i have never worked with a bike kit but i did put it together. it was running ok but it got a leak. it fluds with gas.

please help me, i dont know how to fix it and would like to know what to do before i try to fix it.

What an odd introduction, and first post.
Anyways, Here, I did a search on this site for you.

http://motorbicycling.com/f34/inside-2010-grubee-skyhawk-cns-carb-25062.html
http://motorbicycling.com/f4/motorized-bicycle-carburetor-pictures-how-install-195.html
http://motorbicycling.com/f34/omg-i-have-tune-cns-help-30169.html

 

[Matheneyr3]

Emergency repair for leaking petcock- cap from a beer bottle. punched a hole through with my leatherman, used as you would a regular gasket- Worked great..been on 4 months & still no leaks.

Have fun-Keep Riding!

-Richard

 

[anim8r]

If this is your 1st project, paint the bike.
Take it all apart, sand it, paint it, & put it back together. You'll get to know your bike & adapt to a mechanical state of mind.

Then before you put the motor on, ride it for a few miles with some screwdrivers & wrenches handy. This way you won't be going 30 mph when you find the mistakes you made when you rebuilt it.

 

[rustycase]

What A8r is really a wise idea...
So much to be learned from working on a bicycle!
Skills that will never be forgotten.

Best
rc

 

[mirage]

hi all. finnally got my bike into a useable state, as the standard rear cog with the kit was 48 teeth, it was to high and burning out my clutch, so i got a 75tooth from blow by u. put that on with difficulty, as the chain clearance from the frame was a nightmare. as being a much larger dia, it was higher up the frame and getting narrower. i solved it by making 2 new thin washers ie rag joint. from a car innertube, drilled out the thick rag joint on the inside to take much larger bolts. advantage, the sprocket fits closer to the spokes, in fact butts up against them making a truer and easier set up. no wobble. then i had to use a thick spacer washer on the gearbox out shaft behind the 11 tooth sprocket to get the chain to line up. it all had to move over towards the the centre of the bike,

now it climbs hills very well, does not seem to be any slower. but i still need to try a 9 tooth drive sprocket on the gearbox drive, as i would still like more torgue. can,t seem to get one for my hoot chain drive box.

another simple mod, no one seems to have thought of is the standard idle chain tensioner. all you have to do is make a large 1/8 thick nylon washer, place on the outside. grease the slot and face, make a small wire hook, to put around the bolt. use a nylon lock nut, back to front as the standard bolt is not long enough. and a spring at 45 deg, pulling from the v calliper mount, make a alloy frame clip to go round the frame. adjust the tightness of the nylock nut to make a nice sliding action, may need to file the slot in the bracket higher for more range, but keep it a close fit on the bolt, no play. works fantastic. it is the large nylon washer that is the secret, stops it tipping sideways, for a proffessional sliding fit. bike now reaches 30mph pretty fast, need a 9 tooth on the box though, unless i can change the sprockets in the box to get the same results.

 

[gphil]

Think I saw where you could order a tool to help get the chain threaded on the engine . I found that a old brake adjuster tool works just great. Of course most do not know what that is now days but us old guys do. None the less, works great, even with one end broke off like mine. lol

 

[rustycase]

Here's a twofer...

The pic will show WHY a brand spanking shiny new china motor should be taken apart before starting.

This is a never - run, regarded mfg engine... and look how horrible the gasket lines up with the manifold ! It would seem they did not even try to get the proper gasket, let alone attempt to fit it properly.

AND, the gasket material is brittle!
It would have undoubtedly sent pieces into the cylinder in a short period of time.

and for #2. drum roll...xxx...

The do-hickey rod thingy next to the manifold is a scrap of welding rod I smacked with a hammer a couple times, then dressed with a file to make a screw driver to adjust the idle mixture, and speed, on my cns carby.

Yah yah yah... I've had a gazillion little screw drivers with the magnet on the handles top and a pocket clip just like everyone else... and I've LOST 95% of em working on this or that !
So I made one... that I wouldn't mind losing !
It works well.
and I haven't lost it yet.

rc

 

[bugnut]

Great post Bikeguy Joe Im a new first time builder but will be going out tomorrow and get them bolts and plugs Just got my motor yesterday so its still in the carton will check tank and check for those shavings, Big thank you

 

[peppers]

1.when riding in motor mode on a multi speed bike, its better to use a higher gear, if its a 7 speed and you ride in 7th gear all the time the bearings in the freewheel will wear out much quicker, first gear would be best to 3rd or 4th would be reasonable.

2. if you replace the stock engine mounts with higher quality ones and mount the engine well the little m6 screws are still not adequate, you hit a nice sized bump or maybe a few there eventually gonna break, you MUST reenforce your mounts with something or better yet devise an entirely separate mounting technique.

3. a nice quality epoxy that dose not desolve in gas and is not broken down easily by sunlight or heat has its uses. For example it can effectively be used as a simple and easy way to construct some mount adjustment hardware and is also useful to add additional strength to an already reenforced mount. An epoxy putty is useful to keep in your bag for temporary roadside repair purposes. Obviously it would be a mistake to glue your engine to your bike with epoxy and try to hit the road, try that and you'll probably die.

 

[twelvestringtex]

sooo... this thread is HUGE... and I can't read 11 pages between now and when I'm supposed to meet with the dean.... and I have only my motorbike as transportation.... how do we quit breaking spokes? I'm shredding them with a Honda GX50 and shift kit!