1969 50cc Maverick Minibike Project

ugmold

ugmold

Active Member
#1
#1
I found this this lump of coal on my local Craigs List. Pretty rough shape. Got it for short money but the engines bottom end is seized and I'm thinking I may need to adapt something else to fit in this small frame.

Anyway I'll let the video do the talking.

https://youtu.be/4cdote4hzXc

[video=youtube_share;4cdote4hzXc]https://youtu.be/4cdote4hzXc[/video]
 
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maverick1

maverick1

Active Member
#2
#2
Don't see Mavericks all that often. Same as a Gemini SST. If you want to keep it simple there are Yamaha motors that should bolt right up to it. I have seen a couple of guys that have adapted Honda motors to them but had to do quite a bit of cutting and welding. Just tear into the bottom end and see what it looks like. They are very simple little motors. I am building a Maverick right now and I am going back with a 80cc motor that had been partially full of water at one time or another. Cleaned up well with a little elbow grease. Good luck.
 
ugmold

ugmold

Active Member
#5
#5
Little more digging on the engine seizure and misc stuff.
[video=youtube_share;dLle3Vks8VA]https://youtu.be/dLle3Vks8VA[/video]
 
ugmold

ugmold

Active Member
#6
#6
Update #3. Pulled the rotary valve off the original engine, looks like I'll have to split the cases in order to get it un-seized.
Started on reupholstering the seat, still needs refinement.
Working on mounting a Tecumseh 2 Stroke off a Toro Snowblower for a temporary re-power.
[video=youtube_share;slh8P4SWXAI]https://youtu.be/slh8P4SWXAI[/video]
 
ugmold

ugmold

Active Member
#9
#9
1969 Maverick Minibike Project Part 4
Got the aluminum plate to fit and hold the engine. Carb kit, painted handlebars, disassembled and reassembled the front end, greased it up. Got it started.

I see a potential problem with there not being enough room for a clutch, unless someone makes a super small one like around 3-3/4 diameter. Or change the exhaust.
Still working on the original engine as well, having a tough time removing a seal.
https://youtu.be/08ZfNuEn-EE
[video=youtube_share;08ZfNuEn-EE]https://youtu.be/08ZfNuEn-EE[/video]
 
maverick1

maverick1

Active Member
#12
#12
That is a wide seal. If you have exhausted the normal ways of trying to get it out, take a sheet metal screw and thread into it and that will give you something to grip onto to.
 
ugmold

ugmold

Active Member
#13
#13
maverick1 said:
That is a wide seal. If you have exhausted the normal ways of trying to get it out, take a sheet metal screw and thread into it and that will give you something to grip onto to.
Click to expand...
That was one of the normal ways, lol. The hardest part is that it recessed and tough to not damage the case. I've been making cuts thru it with a chisel, delicate pia work, but will probably collapse it at some point.
 
ugmold

ugmold

Active Member
#15
#15
Thanks for the motivation Maverick. I got it out. I tried another screw and this time instead of taping the vice grips on the screw, I hit the casing with a rubber mallet.

Removed the c clip and finally got the crank out. Both crank bearings were locked up, but the con rod feels good on the crank. Cleaned up the cases a bit with gas and a brush, and cleaned up the toxic work bench area and took a pic of all the nuts, bolts, washers, bearings, pins etc that I'll never remember where there placement...lol.

Would you have an exploded view of the engine in your manual you could take a photo of?
 
maverick1

maverick1

Active Member
#17
#17
I will see what I got and will scan it. It will be Thursday. My home printer scanner died and I will not be back at work then. I actually took a ton of photos with my phone as I tore down the motor and made a reference book. Saved my butt more than once. It is of the 80 but the only difference is the oil pump. Another good reference is Yamaha USA, parts,1964, then YJ1. With the exception of a couple of parts, pretty much the same.
 
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ugmold

ugmold

Active Member
#18
#18
manchester1 said:
Cool bike. I think member "Ond" did one of those bikes. Check the OldMiniBikes build off 2016. I recovered the seat for him.
Click to expand...
Thanks Manchester, couldn't find the "Ond" Maverick, but there are a couple including "Maverick1" that I saw.
Did you see the seat I made...don't laugh, 1st attempt.
 
ugmold

ugmold

Active Member
#19
#19
maverick1 said:
I will see what I got and will scan it. It will be Thursday. My home printer scanner died and I will not be back at work then. I actually took a ton of photos with my phone as I tore down the motor and made a reference book. Saved my butt more than once. It is of the 80 but the only difference is the oil pump. Another good reference is Yamaha USA, parts,1964, then YJ1. With the exception of a couple of parts, pretty much the same.
Click to expand...

Thanks Maverick1, I was looking for a pdf manual, haven't found one yet.
 
maverick1

maverick1

Active Member
#20
#20
The Gemini manual is ok but I always use the Clymer manual for the old Yamaha's. More thorough and easier to follow. PM me your email and I will snap a photo of the book and send to you.
 
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