Update on "Rescued from the Trash" Mini Bike.

#1
Last week I rescued a mini bike from a trash pile. Thanks to member Marcus I found out it was a 70's Sears mini bike.
I restore classic British and European motorcycles full time, so this mini bike is a nice change up. I can't remember what brand my first mini bike was.(Norton_ES2_rider on Instagram.)
It's all apart now, I've got the frame and wheels primed and ready for paint.
I just figured out what a HS40 is, and the motor is in good shape. It still has a good amount of crosshatch in the cylinder so I don't think it had much riding time on it. I have spark after cleaning the points, and I have to fix a few rust holes in the bottom of the shroud caused from damn mice chewing up the seat and stuffing the foam in the engine.
The carb is in bad shape, are the ones on Ebay any good?
Thanks for the help.
 

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#2
I use the China aftermarket carbs all of the time. You can get a bad one here or there, but for $22 on Amazon, the time savings is great and if they fail after a year of ethanol fuel, I just replace it. Now, I still believe saving a tech carburetor is the best route. I think @markus is one of the top guys when it comes to this. I've learned a lot from his tutorials. Be sure to set the ignition timing correctly, as that seems to be the difference between a good, easy stating, strong running Tec and one that takes 20 pulls...
 

markus

Well-Known Member
#3
Just an FYI, That engine is an H35 (3.5hp) Not an HS40 (4hp) That can make a difference in parts and timing etc... As I had stated in your other post the engines model number will be found on stamped on the shroud at the top. It was a terrible place to put them, Tecumseh was in between designs that year and those style shrouds didn't stamp as well as the later squared off shrouds did. Can see where they should be here on this one below as you can see if you have an old one that got the red headed stepchild treatment when it came to long term storage they can be really hard to read. The first series of numbers H35 45**** will be the model number that is used for finding parts lists and how its outfitted. The 2nd series SER (serial number) is the date code. They are pretty basic even when it comes to recreational spec so if they are not legible anymore I can go through my lists and see if I have a number recorded that would be best suited to that year/setup.

 

markus

Well-Known Member
#5
Thanks for all the help, I checked on the shroud and found the numbers.
Excellent, you missed a 4 at the beginning though, looks like a rust divot got the best of that number ;) Its H35 45350J ......and its a late in the year 1974 made engine

Here the partstree link to the pages associated with that model, currently Partstree I find is the easiest to navigate the available online pages for Tecumseh engines although most all suppliers use this info from Tecumseh: H35 45350J

Remember that the parts explosions are "generic" so if you click on something that just does not show up that usually means that your engine did not that get that part. There are a few exceptions, but not a lot. They ( I assume CPC which owns whats left of Tecumseh) also recently did a long overdue update to the available parts, which was good and bad. The good was things that were showing as available you would order, pay for, and then find out later it was something that wasn't available anymore. So they cleaned that up (they sort of the consumer as a way to check dwindling stock). The bad is a lot of part numbers disappeared because they are long gone. For me that sucks because mainly just use pages like I linked to quickly search part numbers and then off to places like ebay to look for "old stock", so now I have to break out my old parts books more often which are a PITA. You still run the risk of having orders kicked back or only parts of your order being shipped as stock diminished, but not as bad as it was a couple years back if you do order from places like partstree or jacks's, etc...

In the link above you will see the main parts lists which you click on and they will expand and have the parts lists. in the middle of the page there is an expandable link though for "attachments to this model" If you open that is will show specific breakdowns for the carburetor, ignition system (magneto), and the recoil starter specific to your engine as well.

Heres the link tot he PDF of the service manual for the Tecumseh L head engines as well http://www.smallenginesuppliers.com...cumseh_L-Head_Engines_Service_Information.pdf

Best of luck with it.
 
#6
Thanks, I do the same with late 50's and early 60's Hondas, they have all the parts listed, pretty much everything is unavailable except for nuts & bolts.
Sometimes the parts diagrams are more useful than the service manuals. I always grab old printed parts books when I see them at swap meets.
Its fun restoring a bike with just 1 wire and engine & drivetrain in one package.
Thanks again.
 
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