1970's Sears Roper Street Legal

Dgroshek

Dgroshek

New Member
#1
#1
Hello all,

I'm extremely new to the mini bike world. Picked up a frame this weekend without doing any research and it needs EVERYTHING. From what I can gather, it was a Sears Roper (not sure if 4hp or 5hp) street legal bike. I would be interested in restoring this back to its original glory but starting my research, it looks like that may be a fool's errand. What should I do here? 20240307_122923.jpg
20240307_121425.jpg
 
Lizardking

Lizardking

Well-Known Member
#2
#2
Dgroshek said:
Hello all,

I'm extremely new to the mini bike world. Picked up a frame this weekend without doing any research and it needs EVERYTHING. From what I can gather, it was a Sears Roper (not sure if 4hp or 5hp) street legal bike. I would be interested in restoring this back to its original glory but starting my research, it looks like that may be a fool's errand. What should I do here? View attachment 312124
View attachment 312125
Click to expand...
Welcome to oldminibikes.com.

Just build it to ride and don't worry about originality.
 
Dgroshek

Dgroshek

New Member
#3
#3
Lizardking said:
Welcome to oldminibikes.com.

Just build it to ride and don't worry about originality.
Click to expand...
Thanks! I don't really know where to start on the rebuild though. I think I need a new fork - at least handle bars and a spring. Other than that, what engine fit in these things? What sort of wheel/tire combo? I do have the original long block engine but is it worth trying to rebuild or just buy a new one?
 
sparkwizard

sparkwizard

#4
#4
Most any vintage flathead engine from Briggs and Stratton or Tecumseh, 3.5 to 5 horsepower should bolt on. The newer OHV engines will fit, and are easier to find. Harbor Freight sells Predator 212 engines for about $150.
I would start cleaning parts and putting them together, making note of bolts and hardware needed. This might be a long term project.
Welcome to the hobby!
 
Lizardking

Lizardking

Well-Known Member
#5
#5
You can try to straighten out the front end or just put a custom one. Tecumseh for the engine but you can put whatever fits without the gas tank attached to the engine and then remote tank it.. Not sure if this is the big wheel model but whatever you can fit safely.
 
Dgroshek

Dgroshek

New Member
#6
#6
Lizardking said:
You can try to straighten out the front end or just put a custom one. Tecumseh for the engine but you can put whatever fits without the gas tank attached to the engine and then remote tank it.. Not sure if this is the big wheel model but whatever you can fit safely.
Click to expand...
There is a bent spring on one of the fork prongs and one handle bar is broken - that I can probably re-weld but the spring is the big issue. Not sure if they're replaceable.
 
sparkwizard

sparkwizard

#7
#7
Ebay, vintage mini bike parts; look around. There are always forks on there.
Personally, I do a lot of welding and (barnyard) metal fabrication and from what I can see on your fork, I would be shopping around before I put much time and money into that one. As stated above, that bike will never be original again.
 
Skipp

Skipp

#9
#9
Becareful with those front springs….i ruined one taking the front end apart….had to have a set custom made….very costly….i have one factory one if needed….
 
markus

markus

Well-Known Member
#11
#11
heres a link to a thread with a good pretty much OG example of your particular model which was the HS40 version (tank mounted on engine), not the Remote tank H50 one: Street legal Roper I am just getting ready to paint the "Example" engine Tecumseh built for the first 4hp bike off the Roper assembly line (soon as the oak tree pollen lets up a little more here in Florida) the info on that engine is shown in the last few posting in the thread but here is the engine during break in the other day.
 
creia

creia

#13
#13
Dgroshek said:
Any chance you know the dimensions of the upper and lower fork bearings? Need to source new ones.
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My 2 Ropers did not have "bearings" per se. They had flanged bronze bushings installed in the top and bottom of the fork tube. If memory serves me correctly (less dependable every year!) I think they are 5/8" ID X 3/4" in length.
Michael
 
massacre

massacre

#17
#17
Skipp said:
They are a very strange size…I searched 2 years and bought several different ones…BDI couldn’t even match them….the person I sold it to made new cups to go along with available bearings…
Click to expand...
My Arco also had strange sized fork bushings, could not match them. Ended up buying some oil impregnated bronze material and had them machined. They came out great, but i wasn't planning on that.
 
Charles S

Charles S

#19
#19
Charles S

Charles S

#20
#20
There is PTFE round stock available on Amazon and eBay, you could turn plain bearings / bushings on a lathe. (Disclaimer: I have not done so but I know that many people have.) The parts wouldn't need any oil or grease.

A few examples:

1" dia

1.5" dia

3.5" dia

4" dia

Obviously, due to cost, you wouldn't want to buy larger than needed...
 
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