Manco thunderbird build

#1
Hey guys, I just recently got into the mini bike hobby and with the help of this site I was inspired and got a lot of ideas for my build, so I decided to finally make a profile and share my build. The bike is I believe a mid 90’s era manco thunderbird that I bought from offer up. Bike was in ok shape except for the seat and handle bars and of course didn’t have the original engine, so I bought a new non hemi predator 212 and went to work. Mods are the following:

engine: predator non hemi-212
-billet +0.20 longer rod
-flat top piston
-Billet fly wheel
- governor completely removed and holes plugged
- mild port and polish on head
- stamped 1.3 ratio rockers
-hot .265 cam
- clear valve cover
-crankcase vented into valve cover
- vm26 carburetor
- “drag pipe” style exhaust
- max torque 3,000 rpm engagement clutch
- new chain (off brand from gps)

frame:
-pro taper style handle bars (Amazon Chinese copy lol)
-handle bar risers
- brass bushing added into steering stem for stiffness
- steering dampener
- new throttle and controls w/kill switch
- gps seat
- new shocks from Amazon, I believe 12 in
- Michelin s83 tires, 3.50-8
- new tubes
-nylon bushing added to seat pivot point at frame

took the bike out for the first test ride and it is SKETCHY, definitely needs more than the scrub brake it has and that factory 72 tooth sprocket really is wild with this engine. I’ve read it would wanna wheely everywhere but I figured with me being about 230lbs it won’t be too bad and boy was I wrong!

Just ordered a 60 tooth sprocket and a clutch brake, sprocket should come today and I’ll keep testing to see if I find a happy medium, I’ve been also toying going with the gps telescoping front suspension to be able to add their front brake kit only bad part is I’d be going down to a 6in wheel with that kit. I only have a few pics so I’ll try and get more.

sorry for the pics being in my apartment, I don’t have a garage of any kind so it’s been built all inside of my living room haha, I have to thank my girlfriend for allowing me to turn the living room into a part time garage
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Triley41395

Well-Known Member
#2
Yeah those bikes with the original sprocket will come right out from underneath you. My brother has one and I don't ride it, way to dangerous. They are cool bikes but with a smaller sprocket or engine.
 
#3
Yeah those bikes with the original sprocket will come right out from underneath you. My brother has one and I don't ride it, way to dangerous. They are cool bikes but with a smaller sprocket or engine.
They are no joke with that sprocket, I would try and ease into it and maybe with just a quarter throttle the front end would just jump up, just crazy, I definitely underestimated that sprocket and with virtually no brakes it’s insane.
 
#8
sweet! I have 3 tbirds myself, got the parts to put a really slick one together but got wrapped up in too many other bikes lol one of these days i'll put it together. one thing you want to do on that frame is box the engine plate in or it will likely flex and crack there. ask me how i and others kno this lol look forward to updates on this one. I also picked up a bird made t bird as well.
 

toomanytoys

Well-Known Member
#9
I like it but how the heck do you ride it with the handle bars so far forward? That would kill me and I feel like it would make the steering wonky.
 
#10
sweet! I have 3 tbirds myself, got the parts to put a really slick one together but got wrapped up in too many other bikes lol one of these days i'll put it together. one thing you want to do on that frame is box the engine plate in or it will likely flex and crack there. ask me how i and others kno this lol look forward to updates on this one. I also picked up a bird made t bird as well.
I have read about boxing the frame up where the engine mount plate is, I wanna do that sometime soon, so far the test rides have been good but I have not pushed the bike at all, still trying to break the engine in a bit and get used to the feel of the bike. It still wants to wheely pretty bad with that 60t sprocket lol thinking about going smaller there also
 
#11
I like it but how the heck do you ride it with the handle bars so far forward? That would kill me and I feel like it would make the steering wonky.

it does look pretty bad in pics, but in person it’s been working out for me as I can lean more forward on the bike and prevent some wheely action, I will play around with the positioning now that you mention the steering, I haven’t felt it too wonky but maybe it might feel better after adjustment. In person that forward lean doesn’t look too too bad haha
 
#12
Another small update, the bike brakes AMAZING with that front disk and the new front suspension is real sweet too, as stated above I haven’t pushed it much but I’m much more confidant riding it. Just finished checking valve lash making sure it’s still good, I had adjust the band on the clutch brake as it got loose and was hitting the chain, and still need to do some more tuning on the carb, pulled the plug and it’s a bit on the rich side
 
#13
I have read about boxing the frame up where the engine mount plate is, I wanna do that sometime soon, so far the test rides have been good but I have not pushed the bike at all, still trying to break the engine in a bit and get used to the feel of the bike. It still wants to wheely pretty bad with that 60t sprocket lol thinking about going smaller there also
yea i'd say anything over 4.0 hp and its a good idea to box that engine plate in.
 
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