New to the Group. Vintage minibike project started.

Mnr81

Mnr81

New Member
#1
#1
Greetings
Im glad to be a part of this group, Im fairly new to this. I do have some mechanical knowledge, but many questions arise in this complete restore.
I picked up a frame from a neighbor for 10 bucks. It's a Grand Prix I think early 70's. I took a Tecumseh 5 horse off an ariens snowblower. Im stripping it down to repaint. I just have very basic questions on parts in general. how many teeth should I get on clutch? What brand clutch? Chain size, what type of brake system? should I do anything special to the engine, carb, exhaust, governor, etc. Thank you in advance its a privilege to be a part of this group...Thanks!!!
 
brown boonie

brown boonie

JUST REMEMBER-EXPECT IT WHEN YOU LEAST EXPECT IT!
#2
#2
welcome to the crazy world of mini's. chain size would depend on what your drive sprocket on your rear tire (#35/#40 chain gear). clutch tooth size would depend on a large part where you plan to ride (off road/on flat pavement/ect), I would recommend a band brake over the clutch. clutch brand would be a personal preference. just don't get a cheap china made clutch, you get what you pay for. as for the engine, a good free flow air cleaner is a good start. there are others here on the site that can help more. again, welcome and best of luck with your build.:thumbsup:
 
Mnr81

Mnr81

New Member
#4
#4
Thanks for your help! What is the best chain size to use? I don't have a clutch, chain, sprocket or rear wheel yet...so its all up in the air. What is the best clutch tooth ratio to sprocket tooth ratio for a 5 hp Tecumseh. I plan on most grass and offroad as opposed to street riding. Thanks again!
 
T

the beekeeper

Active Member
#5
#5
Rear sprocket size would be dependent on wheel size, if your running a 4" or 5" wheel I would go with the 60 tooth and a 72 tooth on a 6" wheel, most of us run a 12 tooth clutch and #35 chain, if your engine is strong I think this combo would work good for you...............................Tom.
 
cheezy1

cheezy1

#6
#6
Post some pics of what you have so far. And those had a 35 chain. So best bet is to track down the wheels and go from there. You can get the sprocket, chain and clutch once you are set on wheels. Also a good old fashion clutch brake is usually the best route. As far as the motor...leave it alone. Just change the throttle part on the bottom back of the shroud to a mini bike one.Tecumseh OEM Mini Bike Throttle Control Assembly That allows you to keep the governor intact and set up the throttle properly. Oh..and welcome to OldMiniBikes:thumbsup:
 
Mnr81

Mnr81

New Member
#8
#8
Thanks for the Warm Welcome and Advice!!!

Wow, you guys are awesome!!! Ill definitely post some pics very soon, because id also like to id the frame possibly. Thanks again for the tips, I will now pick out wheel and go from there. It does have a front tire I measured the rim it was 6" across(radius?).
Im thinking about going with 6" wheel setup. Much clearer now that I know what direction to head first. hub, tire, sprocket(72t), and a 35 chain clutch with 12 tooth...sound ok?

How about clutch preference, should I go with max torque or whats the next step up?

You guys are great this is an awesome group...thanks again and looking forward with chatting with you all and learning.
 
cheezy1

cheezy1

#9
#9
Better off starting with a 12t into a 60t sprocket. That gives you a 5:1 ratio....aka..good top end and not bad take off. The 12t into the 72t (6:1 ratio) gives you great take off...but not much top speed. And Max torque is a good clutch to start with.
 
Mnr81

Mnr81

New Member
#11
#11
Hello All,

Here are a few pictures of the frame I picked up for 10 bucks...it had a Grand Prix sticker on the front...any ideas what this ol gal might be? It came with a 6" front tire, so I think Ill start with a 6" on back and go from there. Should I go bigger on tire size? Thanks!!!
 
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