It looks like i'm alone on this one but i actually really like the Thunderbird for a few different reasons. ** A stock Manco Thunderbird is junk in my opinion*** They are easily modified and i was able to make mine into exactly what i was looking for and more. Here are my major issues.
A) the frame isnt exactly what i would call strong but more importantly (from a safety standpoint) my front forks were completely sheered at the welds. The forks took the most time to rebuild and reinforce. They did come out nicely once i finished them.
B) aesthetically, there is potential for the thundrerbird but the fuel tank and seat have to go. Not even a question. And the cheep plastic fenders as well. Junk... plastic chain guard needs to be replaced as well.
C) The large sprocket isn't a problem for me because this is my comfort/cruiser minibike not my high performance death trap. The extra torque comes in handy as well. The #40 chain has yet to malfunction and it scrapes occasionally. I dont have a problem with the look of it either.
D) The springer seat becomes wobbly and shifty due to poor design ( only my opinion). I fixed this by welding new seat spring brackets to the minibike frame and a fabed up a quick frame for the bottom of the seat where the springs attach to the seat. It still isn't perfect but it is 1000 times better.
E) Power plant is sufficient for everyday simpletons.... GX160 is just rite for this little cruiser.
I love this bike because it provides some form of suspension. I love that it needs to be worked on and there are no rules as to how you chose to strengthen its weaknesses. I think the scrub brake works great. Now when i want to go for a ride I have a comfortable good looking and easy to control cruiser. Great on the street and mild trail riding.
Summary. I do not suggest this Mini for those looking a "turn key" bike that doesn't need modification. ( see pics of front end before I fixed it)
If you are looking for something that you can find and put together on a budget ( as long as you have the necessary equipment/ "know how" to correctly do it).... this is a great design with tons of potential. This is a cruiser not a drag racer. I LOVE MINE