mini bike frame

Mini bikes and hot rods go together right. I found another project for the kids and I . I found a old minibike bare frame for 25 dollars that I want to get going for the kids. I have a small problem though. The frame seems to have got some water in the tube that supports the motor. I does not look that bad to me but will pretty much be impossible to tell over the internet the integrity of the tubes. I want to make some kind of wire brush with a extension on it to send in down the tubes and clean any rust in the interior of the tubes. Then fill the tubes with some type of rust converter/primer. Tap the cracks shut and weld and finish. I guess best would be to cut some tubing in half and weld some pieces in over the cracked area. Then I want to wire brush the frame and put some naval jelly on it to take care of the surface rust and paint. Any ideas on this project are welcomed. Thanks

http://i1105.photobucket.com/albums/...DSCN1304-1.jpg

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Nice find! I still have my dad's Sears mini bike. Still runs too, just isnt too quick with my 300+lb body on it! Haha!

Looks like those tubes that drop down below the engine are open at the back ends. I don't think I would worry about trying to get a brush inside, but if you're worried about internal rust you could maybe thin down some rust encapsulating paint a bit, pour a cup in the tube and turn it every which way to coat the inside and then dump out the extra. That would be after pounding the cracks together and welding them up. The pipes that are sealed both ends and no cracks should be fine, right?

Great find for $25, BTW!;)

Thanks
From what I have found out is that its a RUPP "Continental" from the late 60's. Great its older then I thought.
What would be best to refinish the paint? I was going to use some type of rust converter on the rust and sand, not taking off as much of the original paint if I dont have too. I am stuck with rattle cans though. Heres a pic of 2 bikes thats been restore. Pretty basic bike , but thats a good thing IMO.


http://i1105.photobucket.com/albums/...ba590c76a1.jpg

http://i1105.photobucket.com/albums/...8bikes0025.jpg

Very cool little project. :) About 8 months ago I, for some reason I can't explain. got a hankering to build a mini bike. Found a frame on Craigslist for $ 50, replaced every part on it from an on line mini bike company, and bought a 6.5 hp motor from Harbor Freight. Sprayed it bright yellow, and even put a new seat on it. I took it for a quick spin and it scares me to death, so it just sits, collecting dust now. :o I came to the realization that at 65 it wasn't as much fun as the one I owned when I was 12.:o

If you need any parts, this is the place I bought mine at. Nice people and they carry most everything mini bike related.

Go Kart & Mini Bike Parts

Don

At least my Son got some use out of it.

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Originally Posted by BigTruckDriver

Thanks
From what I have found out is that its a RUPP "Continental" from the late 60's. Great its older then I thought.
What would be best to refinish the paint? I was going to use some type of rust converter on the rust and sand, not taking off as much of the original paint if I dont have too. I am stuck with rattle cans though. Heres a pic of 2 bikes thats been restore. Pretty basic bike , but thats a good thing IMO.

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BigTruckDriver,
When you say you want to "...not take off as much of the original paint...." do you mean you want to keep the old patina, making it look its age; or do you mean that you don't want to strip it to bare metal before painting? If you're wanting to refinish the frame like those in the pictures just sand it smooth, and get a primer and finish color from Krylon or Rustoleum. A metal etching primer would be a bonus if they have it. Rattle can paint is very thin to atomize through that small orifice, so you need to put on three or four thin coats at each step to get a good coat of finish.

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Originally Posted by rspears

BigTruckDriver,
When you say you want to "...not take off as much of the original paint...." do you mean you want to keep the old patina, making it look its age; or do you mean that you don't want to strip it to bare metal before painting? If you're wanting to refinish the frame like those in the pictures just sand it smooth, and get a primer and finish color from Krylon or Rustoleum. A metal etching primer would be a bonus if they have it. Rattle can paint is very thin to atomize through that small orifice, so you need to put on three or four thin coats at each step to get a good coat of finish.

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Thanks for the input guys.
Itoldyouso= your a dare devil,lol. 6.5hp, that motors HUGE. The bike looks beautiful though.
Rspears= No I dont want the original patina , I just didnt want to strip it too bare metal as you said. After taking it apart though I think stripping it would be best.

I'd go with Por 15 for inside the frame. The stuff coats and coverts rust, and a little goes a long way. It is a very thin paint that should take care of any rust issues you have, then maybe go with less of the "Tim the tool man Taylor" approach, as Don said, more power on one of those can be scary!
Had a friend put a huge marine patrol out board on a small cubby cabin fishing boat, used to be like putting your life in your hands going out in his boat, especially before he put a floor in over the exposed stringers. Lightening quick power and no stable platform equals disaster! :)

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Originally Posted by stovens

I'd go with Por 15 for inside the frame. The stuff coats and coverts rust, and a little goes a long way. It is a very thin paint that should take care of any rust issues you have, then maybe go with less of the "Tim the tool man Taylor" approach, as Don said, more power on one of those can be scary!
Had a friend put a huge marine patrol out board on a small cubby cabin fishing boat, used to be like putting your life in your hands going out in his boat, especially before he put a floor in over the exposed stringers. Lightening quick power and no stable platform equals disaster! :)

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POR 15 has crossed my mind,lol. I used the stuff on a rear end and applied it with a brush. It leveled out and is a thick coating that attaches to the metal real good. Have you tried to top coat POR 15 with a rattle can? I think I might sand blast the frame and use the POR to seal the frame up and then top coat. I think that would be as durable as I can do in my garage.

EDIT: looking on the web top coating POR is kinda iffy. 50% say yes no problems and 50% so no bad idea.:confused::confused: Maybe I just do the insides of the tubes as you suggested. I will be sandblasting the frame now(change in plans) I need to go to the paint shop and get some self etching primer and paint in spray cans. What type of paint would be best , most durable, got 3 young ones that will try there best to tear it up,lol?

Don

You've got to have a picture with smoke coming off the back tire. Cmon!

i treated the floor and bed of my 63 willys jeep with POR .
then painted it with farm implement paint.
it worked just fine.
POR left expsoed to sunlight turns an odd grey color.
that stuff is tough!

Just saw this thread - great find on the old Rupp frame. Had several mini-bikes in the 60's - what a blast. I once built a mini-bike with a MAC 101 (two stroke racing cart engine) and that thing would flat out scream - but oh the front end wobble with those little tires!!

By the way, the cracks are caused by water getting inside the frame and freezing (just like a pipe in your house!). I've fixed several of them and you need to know that you can blow right through the tubing if you're not real careful. Of course, my experience was using a Lincoln arc welder and i probably had it set a wee bit to high!

a 3-5 HP Briggs is perfect for these buggers. If kids are going to be primary riders, I'd stay closer to a three horse and keep the final drive a bit higher or they'll launch like a Nike-Zeus rocket. If adults ride a five is okay with a bit more gear through the jack-shaft as we tend to have the "bulk" required to keep the front end down...

Have fun and let us see the results!
Glenn

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Originally Posted by Mark in Memphis

Don

You've got to have a picture with smoke coming off the back tire. Cmon!

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Haha, no smoke, but the front end gets real light when I cranked it open. Then, when I laid off of the gas I felt like I was going to do a header over the handlebars.:eek: I guess I was a little more agile 53 years ago when I had my first one.:o

I agree with Glenn.....3-5 hp is much more sensible. The 6.5 is physically a little bigger (less footroom) plus it is just waaaaaaaaaaaaaaaaaaaaaaaaaaaaay too much hp.

Don

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Originally Posted by Itoldyouso

Haha, no smoke, but the front end gets real light when I cranked it open. Then, when I laid off of the gas I felt like I was going to do a header over the handlebars.:eek: I guess I was a little more agile 53 years ago when I had my first one.:o

I agree with Glenn.....3-5 hp is much more sensible. The 6.5 is physically a little bigger (less footroom) plus it is just waaaaaaaaaaaaaaaaaaaaaaaaaaaaay too much hp.

Don

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Don,
Comparing the pic's of your beautiful yellow bike with the two that BTD posted I noticed that your foot pegs were a lot farther back than the others, which I think would add to the feeling of instability, especially at speed. I would think that having your feet about a foot or more shifted forward would help, but then I've not ridden a mini bike for about 40+ years :LOL:

After looking at the frame pics, not so sure it wouldn't be best to just replace the cracked sections with some new tube and internal slugs to help hold things together.... Hate to see it break there, underpower with a rider on it!!!!

You are right, the footpegs should be up front but that engine is too large and took up the spot where your feet would lay comfortably. So the only alternative was drag bike style, behind the engine. I think wheelie bars would help, maybe that is next...........after all, the Billetproof drags are coming up in October and they have a minibike class.:D

Don

Here is what mine looked like when I bought it. Someone had cut off the engine mounting plate, so I had to redo my frame and straighten it as it was bent from years of abuse.

Thanks for the help and ideas. I found out that its not a Rupp "continental" but its actually a Rupp "Digger":3dSMILE: Same bike but has a gas tank mounted on top.
http://i1105.photobucket.com/albums/...n12/digger.jpg

I sent a wire brush down the pipes , actually a home made brush made with long lengths of welding wire with the ends bent about 5 feet long hooked to a drill.:eek: Very dangerous but it seemed to work. When I flipped the frame over I did not see any big rust particles come out (good sign) , but there was some black fine powder:confused:.

Seeing the bulge in tube it makes since that water got into it and froze. Glad that it is from water freezing and not just rusting out which would be worse,IMO. I spent a few minutes late last night massaging the bulge with a brass hammer to try and lay it down evenly. The metal is still pretty tuff but its moving, so I think the metal in these areas is still pretty good. Gonna try and get it weld up today , I will get some pics.

As silly as it sounds, building one of these is a lot more fun than building a car, I really enjoyed restoring mine. They are so simple and not very expensive to restore. I have just about $ 400 in mine, including the on sale HF motor at $ 99.00. The only mistake I made was thinking that more hp would be better..........should have put nothing bigger than 5 hp on it. A 5 would have also been physically smaller and left more room for my legs and feet.:o

I might fab up some wheelie bars and give it another try. :D

Don

Built one of these for my boys some 40+ years ago.. Wife got peed off cause I did it. The boys loved it then she got on it to go down the street a cop stoped her hahaha. He told her she should know better.

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Originally Posted by cffisher

Built one of these for my boys some 40+ years ago.. Wife got peed off cause I did it. The boys loved it then she got on it to go down the street a cop stoped her hahaha. He told her she should know better.

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.........kharma......:HMMM:

I have a TC 100 frame, have a vintage B&S 3.5hp ( model 5S 1953 serial number ) engine that I want to rebuild for it, but I'v wanted to for the last 10 years. just no time

I got the bulges tapped down and welded up. The straight one was no problem the one on the bend was a little harder, but I think they will do. Luckily , and what has probably save the frame all these years is the use of shocks on the frame.
Time to start with painting the frame. Looks like it has enamel paint on it.

Before welding
http://i1105.photobucket.com/albums/...2/DSCN1308.jpg

This one was a little harder due to the bend and thinner material at the bend. I had to stick a screwdriver in the slot because the metal in the middle of the crack wanted to fall below the other edge before it got into position, and I ended up with a gap. I tacked the crack up and added more material in the area.
http://i1105.photobucket.com/albums/...2/DSCN1309.jpg

Welded up.
http://i1105.photobucket.com/albums/...2/DSCN1316.jpg

http://i1105.photobucket.com/albums/...2/DSCN1317.jpg

Nice job on the cracks, frame looks great!!!!

Thanks Dave.

Yep coming along very nicely! Great job on fixing the cracks.

Steve is right, you will be fine with those welded like that. BTW, Northern Tool carries a few mini bike and go kart parts like tires, wheels, sprockets, clutches, etc. They have a section devoted to them and the prices aren't horrible.

Check online and in the store at Harbor Freight for an engine. They go on sale often and usually in the $ 99.00 range. I looked at their website for you and the only one I saw was the 99cc one shown below. From what it says, this is a replacement for a 3hp engine, and would be about right, especially for a kid using it.

The one I bought for $99 was a steal and is really a very good engine.........fires up on one pull and runs smoothly. Just a bit more hp than I needed.

Don

Thanks Don, I looked briefly at harbor freight over the week end and did not see that one. I will look a little more today, it was late and I just did a quick search. I would like to find a older motor that is rebuildable but will do the Harbor Freight deal also.
Has any tried this for rust?
http://i1105.photobucket.com/albums/...r_solution.jpg
I bought a bottle about a year ago to try out and never got around to it until now. The rust was 100% removed in 12 hours from all the small parts. I am happy with the stuff , will have to look into it a little more.
I was able to disassemble and clean up the shocks with the rust remover also and it looks like I will be able to use them, so thats a plus.
I am still not sure how to paint this thing. I could buy a cheap one time sprayer from harbor freight to paint but I want to paint to last. What it has on it now seems to be enamel. Would powder coating be better then anything I can spray?

Powder coat seems to be the most durable finish. It's thick and durable, where if you scratch it, you'd probably not penetrate to metal, where as spray on you'd need lots of top coats to achieve the same level of thickness. Either would be fine, but if powder coating doesn't cost too much, it will hold up better to anything your kids throw at it! :)

At $ 99 on sale, you can't beat the HF price on motors. I first bought a 5 hp at a swap meet for $ 50 and had to buy a carb kit and other small stuff for another $ 40 and it never ran right, so I sold it and opted for the brand new one from HF. I don't know how they sell them for that money, they are really not bad at all and have a good warranty.

As for paint, I bought a quart of yellow Rustoleum paint and sprayed mine over epoxy primer. It took a little longer to cure than the 2 part paints we usually use, but in a few days it was as hard as a rock.

Don

Yep, you cant beat 99 dollars for a new engine. Ill have to go up to the store to see if they have any in store specials. I checked them out and the websites lowest price is 140 , not to bad for a engine I will use just to fart around:LOL:. I checked out Northern tool and supply also but their prices are way to high and they dont have anything really. I did find some bearings for the handle bars and paid 11 dollars for them , got home and check online to find the same brand and parts for 1.50 each:eek:. My Plans have changed though , the mini bike will now be mine,lol. I will have time to look for original parts since the kids wont be using it.:LOL: I will mainly use it at the race track to get to the staging lanes, or swap meets and to haul ars to the the blue house.:LOL:
The guy I got the mini bike frame had a go cart I could not pass up and I will use this for the kids. 150 for a Manco Dingo go cart minus the engine but does have the torque converter. It looks like this, but not as pretty:D
http://i1105.photobucket.com/albums/...man12/5955.jpg

Not preaching, and you're likely aware but be careful letting the grandkids ride that cart on the streets. They don't realize how easy it is for a driver to overlook them in a car or truck, and kids aren't always overly observant, either. Around here the city police get pretty harsh with the kids, and for repeat offenders they come after the parent/grandparent for endangering a child - nasty stuff for just having some fun.

Yes, thanks for looking out. They will not be riding on any streets or asphalt. These things are fun but very dangerous and have to be supervised. I have heard to many stories of kids and grown ups getting hurt missing fingers,etc. I will do my best to make sure they are safe(safety first), helmet , safety glasses, and supervision . Only open fields and dirt. Plus my kids are small so I will put a limiter on the throttle and they will be happy with just moving around at 5 miles a hour. Both will have one of those tall ugly flags.

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Originally Posted by BigTruckDriver

Yes, thanks for looking out. They will not be riding on any streets or asphalt. These things are fun but very dangerous and have to be supervised. I have heard to many stories of kids and grown ups getting hurt missing fingers,etc. I will do my best to make sure they are safe(safety first), helmet , safety glasses, and supervision . Only open fields and dirt. Plus my kids are small so I will put a limiter on the throttle and they will be happy with just moving around at 5 miles a hour. Both will have one of those tall ugly flags.

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You've got it covered, and I know why they love to come visit!! They'll have a ball!

Nice cart too. We used to ride one of the Honda Odessy's around the ranch in Wyoming. They even used it to heard the horses. It would fly! Much fun was had in that thing!
Check Harbor Freight this weekend for their Memorial Day sale. Might find some better deals on motors, during the sale.

Harbor Freight is always running some sale. If you don't see it today, check back in a week or two and they will have the item you want on sale. Also check their website and if it is there print out the ad and take it to the store, they will honor it.

The one I got for $ 99 is really a nice engine, but the day I bought it they brought out my motor and put it in my trunk. When I got to the shop I took it out and found they had mistakenly given me a 13 hp electric start one for $ 99. !!! For just a second that devil on my left shoulder was saying "Shhhhhhhhhhhhhhhhhh !!!!" But the angel on my right shoulder won out and I took it back and told them they made a mistake. The $ 13 hp was something like $ 350, I think. :eek::D Bet that would have moved my minibike !

Don

Just got the Harbor Freight flyer in the mail today. They are advertizing Predator engines, including a 3.5 hp horizontal shaft motor for 109.99, if you get one of their 20% coupons on the internet this will be less than 100 bucks(87.99) for a new engine. they also have 11 and 13hp engines, but I think that would be a little scary!:)