SE Woods

[Shnitzl]

not 100% sure on all the details of this mini bike.
picked it up non running and just recognized the intake design. can someone tell me the engine model?
I can't see anything on the engine itself.

I had one of these so I slapped it on as the spark was weak with the points

https://enginebore.com/collections/quality-ignition-parts/products/electronic-ignition-universal

id be curious if others are using this, pro's con's

it runs fantastic but starting is slightly difficult BUT I think that has to do with my fixed jet carburetor.

anyways a video on the install to keep me occupied during these trying times.

I will try to make more if the membership thinks its enjoyable to watch

 

[Havasu Dave]

It's admirable that you are making this attempt. Getting spark is one thing. Getting it at the right time is another. Your Tecumseh is meant to be timed by first setting the points at .020 at TDC, then the piston backed off to a specific distance BTDC. That is anywhere from .035 to .065 inches before TDC, depending on the model of engine. That is accomplished by moving the magneto mount plate until the breaker points just barely open, as checked with an ohm meter. That is what sets the timing, not the "point gap" that I just read all over the internet. These NOVA and other solid state systems do work on the later Tecumseh's with the external coil from what I gather. I have yet to see anyone successfully use on of these on an older Tecumseh using the original flywheel and magneto.

That is a neat bike that hails from Canada. This engine is either HS40 or HS50. I don't know if it was original to the bike. It appears the data plate is missing off of the front of the shroud. Despite the fact that I've rebuilt a bunch of these, the only way I can tell if it's a HS40 or a HS50 is to measure the bore. That engine is getting harder to find, more expensive, and I recommend hooking it all back up and getting the correct carb for it and riding it. But that's just me. There are way smarter folks on here who can talk about all of this, so maybe one of them will chime in.

 

[Shnitzl]

It's admirable that you are making this attempt. Getting spark is one thing. Getting it at the right time is another. Your Tecumseh is meant to be timed by first setting the points at .020 at TDC, then the piston backed off to a specific distance BTDC. That is anywhere from .035 to .065 inches before TDC, depending on the model of engine. That is accomplished by moving the magneto mount plate until the breaker points just barely open, as checked with an ohm meter. That is what sets the timing, not the "point gap" that I just read all over the internet. These NOVA and other solid state systems do work on the later Tecumseh's with the external coil from what I gather. I have yet to see anyone successfully use on of these on an older Tecumseh using the original flywheel and magneto.

That is a neat bike that hails from Canada. This engine is either HS40 or HS50. I don't know if it was original to the bike. It appears the data plate is missing off of the front of the shroud. Despite the fact that I've rebuilt a bunch of these, the only way I can tell if it's a HS40 or a HS50 is to measure the bore. That engine is getting harder to find, more expensive, and I recommend hooking it all back up and getting the correct carb for it and riding it. But that's just me. There are way smarter folks on here who can talk about all of this, so maybe one of them will chime in.

thank you, my theory was that the engine must have run prior to my ownership. because the ignition module replaced the points and condenser entirely that is one things out of the equation.

so if I did not loosen anything I wouldn't loose the timing - I would guess the magneto needs to be timed so I left it well enough alone. so if this was never touched it would still be at factory setting or as it was when it was running. so no need to take the head off and time



I am happy to report that the module works extremely well. I just put a fixed jet tecumseh carb from a Hs50 on it.
idle sometimes stalls but works well for now. the governor is not hooked up and at wide open once it gets to the point of keeping its pace will go in and out of power (not sure if this is the carb again being fixed jet - no governor - or the ignition module)

time will tell, but I have been flying around on it for a few hours and still going well.

I do live in the great white north, I can state that tecumseh HS50's are a dime a dozen here. (mainly because of snow blowers)

 

[Havasu Dave]

Great! The down side here is that if you ever have occasion to loosen that plate like to change the magneto, you will have to use the points to time it to get the Nova to work. You can't time it with the magneto alone. There simply is no indexing. Perhaps it would be a wise idea to mark the magneto plate against the bosses or something, just in case you ever have to replace the magneto. (Create the index) Good job. This has been discussed before, but never in the guise of someone who has not moved their stator plate.

If it still runs bad, I'd blame the carb. I know what you have and it sucks for a mini bike. FYI, a few of us have made some hot rod engines using points. It was always a wish that we could create an electronic ignition where we could advance the ignition for hot specially ground cams, or retard the ignition for easy starting of high compression engines. Anyway, have fun!

 

[Shnitzl]

thanks Dave.
I thought the same for timing, I left the points and condenser in for this reason. I should have noted that in the video.
I like the marking idea as well.

I put an adjustable carb on my snowblowers tecumseh last year so I will swap them! I will report back.
was thinking I could also do a 19mm slide carb.

im not sure if the module has an advance built in, I will need to research that.

good to hear you can have success with points on engine builds, its something I would like to try in the future.

anyone know stock setup safe rpm? I want to check my high speed run on what rpm I'm getting. it doesn't sound to unreasonable but I don't want to blow the engine up.

I would even contemplate putting the governor arms and linkages back on if someone had them.

 

[Havasu Dave]

thanks Dave.
I thought the same for timing, I left the points and condenser in for this reason. I should have noted that in the video.
I like the marking idea as well.

I put an adjustable carb on my snowblowers tecumseh last year so I will swap them! I will report back.
was thinking I could also do a 19mm slide carb.

im not sure if the module has an advance built in, I will need to research that.

good to hear you can have success with points on engine builds, its something I would like to try in the future.

anyone know stock setup safe rpm? I want to check my high speed run on what rpm I'm getting. it doesn't sound to unreasonable but I don't want to blow the engine up.

I would even contemplate putting the governor arms and linkages back on if someone had them.

About 4200 RPM is as high as you'd want to go with a solid engine. The connecting rod breaks at the crankshaft journal when it turns too fast. On the higher RPM engines, we use an aluminum billet rod- not that "billet" is stronger, but because there is more of it. In addition to the cam, we add more robust valve train components, and fancy carburetors. (Mikuni for me)

Clean, quality oil changed often and a couple of designated brain cells to your throttle hand are pretty good ways to keep from blowing up any engine.

No ignition module or points set up for these has advance/retard built in. This is not an issue for stock engines. Governor arms and linkages are available, as are springs. With that torque converter, under normal operation you should not have a problem with over-reving the engine.

There are neat carburetor options such as a PZ-19 off of Ebay. Look it up. A Chinese clone of a Keihin carb, they are CHEAP, and work very well. Your challenge is to use enough JB Weld and fancy drilling to get them to work on your intake manifold, OR get with a local fabricator or machinist and have a straight intake manifold welded up. You will have to figure out your throttle cable- I use hard solder and a tiny length of brass tubing as a "slug"- but anyone who can cobble up that ignition and make it work, could handle all of that, and it would run way better than any Tecumseh carburetor would.

At the risk of having the loyal membership roll their eyes once again at my shameless self promotion of the one engine I ever built in my entire life, (not really, I've built several as a hobbyist, Father, Grandfather, and Day Time Soap Star) here is a video of a special built HS40 on a modified Cat mini bike. Yes, that fat old man is me from two years ago.

 

[Shnitzl]

thanks Dave,
this one is a jack shaft.

good info all around.
I will buy one of the pz19 carburetors, I should be able to fab something to mount it up at home.

thats a awesome bike you have, I would like to make one fly like that.

hope to make a new video soon