My Sears/Bird Nighthawk project

#1
Just joined here recently and have been doing small things to this mini since I got it 2 weeks ago. Did the basic tear down, inspection and cleaning, no painting or anything yet. Have been concentrating on seeing if the motor was any good before going forward. Finally found all the parts like head gasket, carb gaskets, filter, vent gasket, points and condenser, carb kit and fuel fitting. The head had only a small amount of black carbon buildup that cleaned up in a minute, I dont think this mini was run much. I got it fired up today and have a leaky carb fitting so will have to address it. It idled nice and the clutch engages nicely since I cleaned it up and lubed it. No smoke, no odd noises. No throttle yet Ruppparts is out of stock. I rode it just a minute by working the throttle with my hand. This has nice torque to it!
I bet I can wheelie my 175lbs on it! Gotta get some more things for it then think about cleaning up the frame and better tires. Wish I knew when this one was made. It has a Sears sticker on it anyone got old Sears advertising? Engine is an HS40 55390D.
Rob
 
#2
Looks good! :thumbsup: I haven't done anything to mine but thanks for telling me my front fender was backwards, I didn't even notice. :doah:

Funny how they look big in pic's but are small bikes. The HS 40 is the stock engine for these bikes. (good engine) I never tried a wheelie but it sure GROWLS like hell and has a cool sound to it with the muffler (almost two stroke-ish) I've only seen a pic of ONE (on mini doodle) untill two of you here picked one up and one showed up on Ebay. Not a whole lot of them out there. :thumbsup:

BTW, throttles are everywhere so don't let that hold you back. :wink:
 
#3
Who makes a good throttle? There is another one Sears/Bird like ours locally but its a real mess and missing nearly everything and way overpriced too.
There is another one on Minibikecentral.com also thats a mess of parts.
This one is small enough that it fits in the trunk of my Camry! I will be making some plywood spacers to lift the seat at least 2 inches higher than stock.
 

07D675

New Member
#5
Thought I'd chime in here since I also have one. I need a stinkin' tecumseh for mine dangit!!!!! Been looking on craigslist but only found one around me on an old snowblower. Finished up an old briggs but it's just not the same.
Might be nice enough to paint today tho'... 62* today here.
That mini looks good Rob... Try MFGSupply.com. for the throttle. I bought one and it looks pretty sturdy. The throttle is metal not plastic. :thumbsup:
 
#6
Ok, just got my throttle hooked up and decided to do a test ride...
This is a smaller minibike frame wise with a short wheelbase. You dont want to be sitting near the back of the seat and go full throttle. It dumped me off the back and I was holding on trying to shut it down! Good think I installed the kill switch today too! My throttle is sticking and boy did it! No harm done but it is super easy to wheelie this thing with just 4hp on it. This is not like my 1970 minibike where you gave it full throttle, and maybe a little push to get going. This one goes like crazy, with that huge sprocket on the back it
can hillclimb I bet. Will have to clear up the throttle problem with a spring and
some lube, Any ideas on how to make the power come on more gradually?
Maybe move the governer spring to another hole? First time on a mini in nearly 40 years! I do have about 75,000 miles of motorcycle experience on street and trails... Motor is purring like a kitten...
 

Hent

New Member
#7
Looks good Robsbird.

I just picked up one of these.





and also have another one of the birds with the rear suspension... i think delrey has one too?
 
#8
Ok, just got my throttle hooked up and decided to do a test ride...
This is a smaller minibike frame wise with a short wheelbase. You dont want to be sitting near the back of the seat and go full throttle. It dumped me off the back and I was holding on trying to shut it down! Good think I installed the kill switch today too! My throttle is sticking and boy did it! No harm done but it is super easy to wheelie this thing with just 4hp on it. This is not like my 1970 minibike where you gave it full throttle, and maybe a little push to get going. This one goes like crazy, with that huge sprocket on the back it
can hillclimb I bet. Will have to clear up the throttle problem with a spring and
some lube, Any ideas on how to make the power come on more gradually?
Maybe move the governer spring to another hole? First time on a mini in nearly 40 years! I do have about 75,000 miles of motorcycle experience on street and trails... Motor is purring like a kitten...
Hey, get a new cable first thing. (under $3) The gov is adjustable by using the set screw that controls the spring but you may just need a stronger return spring (or extra) The sproket is big but so are the wheels so thats moot. Tecumsehs have torque for their size. :thumbsup: Sitting on the back could be trouble. :doah:

Hent, hows the Ebay boycott doing? :thefinger:
 
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delray

Well-Known Member
#9
yes hent my bird has rear suspension,but i still dont know what model it is:doah:
Robsbird,it kind of sounds like your spring set is hook up wrong or maybe even the wrong governor spring on the bike? maybe some pictures of your spring set may help? good thing is you know it has good power:thumbsup:
also you must have the correct large rear sprocket on the bike just like hent's bird. this will give you that lowend power to take of good and also let the clutch lock up good too.
i think all birds with rear suspension also came with a torque converter and with a smaller sprocket? still not sure on this? just on what i have seen posted in the past from other guys bikes.
 

Jleon

New Member
#11
I believe all t/c driven clutches are adjustable as are some centrifical clutches? Just a thought. Couldn't see what you're running.
 
#12
Delray, I double checked the setting for the linkage and they are correct.
I do not have a spring on my throttle assembly but will add one before my
next ride.
Hent, did you get the slanted intake and carb with it? These are popping up
all over the place now.
 
#14
Made a bracket to hold one end of the spring since I could not find
a proper spring. Works much safer now. Took it for a nice ride today.
Since I dont have the proper carb, I am sure it could be faster with
the right one. I also recommend the MFG supply throttle now. It has
an adjusting ferule that I used to set my idle speed since I have no
screw on this carb to set that with.
Rob
 
#15
Done for now!

Got this one as far as I will take it for now. Paint will come later if I keep it.
It runs great, plenty of torque to move my 175lbs around. Heres the list of what was done: General cleanup, new thottle, killswitch, seat, chain, carb kit, spark plug, head gasket, intake/exhaust gaskets, air filter, oil change, cleaned out gas tank, fuel line with shutoff, new points/condenser,new tubes, new 3.00 x 10 inch tires, correct engine decal, made a new scrub brake as the new tires were larger than the 2.50 x 10s that came on it. Shocks were rusted stuck so I had to fix that with a sledgehammer.
I may paint it later this year but I am in no hurry.
Rob
 
#17
i picked mine up about a year ago but i have'nt had time to start a restore on it yet, tank is not in very good shape and it does not run yet (no fire), were they all black and white ?

 
#18
Looks real nice and I like the wider tires. That aftermarket seat works real well on it too :thumbsup:

Funny, when I got mine I couldn't find any anywhere and this year a few showed up. :doah:

I haven't done anything to mine yet since it was pretty clean the way I found it at a garage sale. Mine must have had the front shocks removed at some point . Do the forks rattle like some bikes do with that style shocks? My sears bike was sloppy as hell.

 
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#19
i picked mine up about a year ago but i have'nt had time to start a restore on it yet, tank is not in very good shape and it does not run yet (no fire), were they all black and white ?
They also came Black and red,, I think I have a black tank like that in the parts bin.
 
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#20
Wildman, that looks just like mine! It looks like your shocks are fully compressed and that is why the front fender is so close to the frame.
I have seen black and white tanks on these. I got the seat for mine on Ebay
for $15, someone has a bunch of them. I bolted it to the original seats board.
GTO, no rattles from my fork, The wider tires are very nice from bike bandit for $13 each. If you go that route you will not be able to use the original scrub brake.
 
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