Honda 5.5 BMX

Carlman

New Member
Dec 3, 2008
22
0
0
Perth, WA, Australia
Hey guys,

Just ran across this here forum on my google search on big block bikes.

Just a bit of background info on me first off. I first put a motor on my bike about 6 months ago. 21cc mitsubushi TM21 on a Shogun Trail Breaker 3. 30mm bike peg friction drive, pre knurled. Went ok as power assisted but bogged down like crap at the scent of a hill (as you would expect).

From there i put a 26cc WW engine on a 16" kids bike with black plastic wheels and no pedals, spindle size of 12 mm (was built for offroad fun for my bro).

Scince then ive collected many engines and stripped them of parts (if dead) or experimented on if going.

My latest excapade was to put a 5.5hp 160cc honda on an old 50cc steel scooter, 70km/hr enough tourque to get up all but one hill so far. But alas i am bored of spending $70 for a tyre every 2 weeks from wheelspining it too much! (i love burnouts lol).

So i have decided to mount this engine on a modified BMX frame like this person has done with his project: (youtube address eludes me at the moment)

Basically just a shelf for it in a modified V of the bmx.

Today i purchased a 96 tooth 35 pitch sproket to go with my allready existing 12 tooth clutch and chain. My rear wheel will be a trash picked triple wall bmx rim (perfect), yet to find a frame after my old one was chucked out whilst i was asleep to the garbage man...:(

I am picking up some 5mm ally plate tomorrow to make a sproket carrier to join the sproket to the bmx rim via a disk break carrier that has same threads as a bmx freewheel.

Glad to be a part of this forum guys, comments and sugestions are welcome.

Will keep you updated,

Carl.
 

xPosTech

The Old Master Motorized Bicycle Builder
Oct 23, 2008
209
0
0
SETexas
Welcome to motorbicycling.com, Carl. We're glad to have you join us.

Ted
 

Weedylot

Angry Old Fart
Jun 12, 2008
453
1
0
Tucson Arizona
160cc is mighty. I'd like to get my hands on one of those.
I saw a 5.5 HP on a cruiser this summer. (Somewhere in the "I saw you..." thread) The guy was barely above idle at 25 MPH. The engine was high in the frame though. I thought it looked a little too high for the CG. :D
 

Carlman

New Member
Dec 3, 2008
22
0
0
Perth, WA, Australia
Just bought a 30$ mcholuc eager beaver 33cc chainsaw off some old people that thought it was buggered (really just a kinked fuel line lol).

So im now mounting it to a kids 16inch bike with no pedals (to replace the ww engine) with a 30mm bike peg spindle, should go just fine

Not much progress on my 160 as of yet, still going over it in my head, im a planning kinda guy.

And whilst im here, i have a walbro WT81 carbie from a WW that has 3 nipples, a sealed up primer bulb hole and looks brand new. There is some old rubber from a fuel line stuck on one nipple on the primer side and the other is clean, there is also a black nipple on the other side which is larger.

My question to you is, what goes where? ive only dealt with carbies that have 2 nipples.

Here are some pics of my carbie and the kind of bike i hope to end up with using my engine
 

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Technocyclist

Motorized Bicycle Senior Technologist
Jul 7, 2008
463
0
0
Asia
Just bought a 30$ mcholuc eager beaver 33cc chainsaw off some old people that thought it was buggered (really just a kinked fuel line lol).

So im now mounting it to a kids 16inch bike with no pedals (to replace the ww engine) with a 30mm bike peg spindle, should go just fine

Not much progress on my 160 as of yet, still going over it in my head, im a planning kinda guy.

And whilst im here, i have a walbro WT81 carbie from a WW that has 3 nipples, a sealed up primer bulb hole and looks brand new. There is some old rubber from a fuel line stuck on one nipple on the primer side and the other is clean, there is also a black nipple on the other side which is larger.

My question to you is, what goes where? ive only dealt with carbies that have 2 nipples.

Here are some pics of my carbie and the kind of bike i hope to end up with using my engine
3 nipples?
1 nipple goes to the fuel tank to get fuel.
1 nipple goes to the fuel tank to return fuel.
1 nipple goes to the intake to suck fuel fumes.

I have the same carburetor, and the shop just finished my modified intake manifold to accomodate this 3rd nipple. I might finish my installation over the weekend.
 

Carlman

New Member
Dec 3, 2008
22
0
0
Perth, WA, Australia
3 nipples?
1 nipple goes to the fuel tank to get fuel.
1 nipple goes to the fuel tank to return fuel.
1 nipple goes to the intake to suck fuel fumes.

I have the same carburetor, and the shop just finished my modified intake manifold to accomodate this 3rd nipple. I might finish my installation over the weekend.
confused... caould you be so kind as to elaborate?
 

Technocyclist

Motorized Bicycle Senior Technologist
Jul 7, 2008
463
0
0
Asia
Try this: http://wind-drifter.com/technical/WalbroServiceManual.pdf

I think you can find your answers on page 26 and 28.

1 nipple sucks fuel from the tank.
1 nipple removes the air from the fuel line and returns the fuel to the fuel tank.
1 nipple is for the impulse to pump fuel.

If you need further clarifications, just reply to this thread. I'll try to get some pictures to show which nipple goes to where.
 

Technocyclist

Motorized Bicycle Senior Technologist
Jul 7, 2008
463
0
0
Asia
am i right in assuming that you still have an inline primer on the return?

thanks alot mate!
My carburetor has a primer bulb at the bottom. The primer can be inline or built-in with carburetor. Depends on your preference, but I think newer models have it built-in. :)
 

Technocyclist

Motorized Bicycle Senior Technologist
Jul 7, 2008
463
0
0
Asia
you can get the primer bulb from this:
av489

or in other Goped shops. I don't think an inline primer is still available in the market. But most of the Walbro carburetor parts you can get at the same link above.
 
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Technocyclist

Motorized Bicycle Senior Technologist
Jul 7, 2008
463
0
0
Asia
not really sure,because as far as I know the 3rd nipple is for the diaphragm inside the carburetor to act as a fuel pump. Maybe it does offer some advantage separating the impulse vacuum from the venturi vents.
 

xPosTech

The Old Master Motorized Bicycle Builder
Oct 23, 2008
209
0
0
SETexas
Those WW carbs that have only two nipples have an internal crankcase pulse port. The carb you're holding merely has an external connection so it will be a universal fit to many engines.

That internally connected pulse port has a habit of plugging up, by the way. The external would seem to be more reliable.

Ted