Bolt on performance mods for h35?

[Travachu]

Hello! Awesome forum you guys got here.
I have a old bird sprite minibike with a 3.5 hp Tecumseh on it. I am looking to get some more power out of it. Are there any headers that will bolt on? And any carburetors that will bolt on and create a little bit more power? I am not the best fabricator, and don't have much for machining tools, so creating a header is last resort. Thanks

 

[minibikefever]

Hello! Awesome forum you guys got here.
I have a old bird sprite minibike with a 3.5 hp Tecumseh on it. I am looking to get some more power out of it. Are there any headers that will bolt on? And any carburetors that will bolt on and create a little bit more power? I am not the best fabricator, and don't have much for machining tools, so creating a header is last resort. Thanks

Welcome to the forum, The gas can, the starting fluid, the recoil and not to mention the rear fender, WELCOME my man that's what it's all about making it happen with what you have and wearing a smile when you fire it up and just run it til something let's go and fix it again lol, I don't have the knowledge your looking for but hopefully someone will chime in with a couple thoughts and get you a little more power, enjoy .....

 

[cfh]

To be honest there isn’t much available for tecumseh h35. In fact there may be nothing available as far as performance mods for the h35

frankly I think you’re better off getting an HS40 or even better still an HS50 motor. Then you can get a performance cam, Billet rod, rings seem easier to get, etc. etc.

it’s the same amount of work to rebuild and modify an H35 as it is an HS50. And I expect you’re no longer 10 years old and weigh 80 pounds. So the added horsepower of an HS50 would certainly be welcome. In addition, the two motors look nearly identical. So it’s a really easy transition.

i know people wanna be all mister original and that, which I guess is fine. But if you actually ride this stuff, a 3 1/2 hp motor with a 200 pound dude on it, doesn’t really work all that well…

You can read up on HS40 and Hs50 modifications at this website www.pinrepair.com/minibikes/tecumsehmb.htm

 

[Lizardking]

Hello and welcome to the oldminibikes.com show!

Like said, not much if any after market support for those engines. Just put a clone on it since there is lots of upgrades available for them. Predator is the most common one to use for it's availability, performance support and price.

 

[cfh]

i draw the line at the predator thing. no 70s mini bike should have a predator. but yea parts galore for them and they do run great. but a predator ruins the look of a vintage mini...

 

[Skipp]

I’ve put a 16mm carb on…open exhaust not much more performance but that carb made it fun to ride….

 

[toomanytoys]

i draw the line at the predator thing. no 70s mini bike should have a predator. but yea parts galore for them and they do run great. but a predator ruins the look of a vintage mini...

I agree and disagree. If it’s a really nice bike I’m going to make original I’ll keep an original engine. But if it’s a rider. Clone all day. Runs better, parts galore, and so much cheaper.

I have enough cash in restoring a lighted H50 for a heath kit hill topper that I could buy a few clones! And it runs great but my tillotson with a tav runs over it.

 

[cfh]

I agree I did that to once to a side popper h35 with a 16mm slide carb and an open exhaust. It did help but not enough to justify keeping that motor. It was a speedway and I ended up putting a HS50 on it and it made a huge difference.

 

[delray]

newer side poppers will accept the billet rod and you can install a hot coil that will make a difference when running a round slide carb and a good header. enough help it get out of its own way...lol

 

[cfh]

Where are you getting these hot coils? They never come up for sale for any of the Tecumseh motors

 

[delray]

Where are you getting these hot coils? They never come up for sale for any of the Tecumseh motors

the ones I'm getting are in my basement on a shelf.... lol. did you ever try you're coil out.

 

[markus]

the ones I'm getting are in my basement on a shelf.... lol. did you ever try you're coil out.

I think you got in that the 5 for one price deal that ugly chicken had on them back in the day to didn't you? Miss those days! I Had hot coils all over the place for awhile

 

[delray]

I think you got in that the 5 for one price deal that ugly chicken had on them back in the day to didn't you? Miss those days! I Had hot coils all over the place for awhile

i only got maybe half-a-dozen laying around. someone got a ton of them in their basement for sure. guy Ebay must have had hundreds of them and someone in the states purchase them. so, they got to be out there?

 

[Skipp]

The “hot” could you speak of, I assume for Tecumseh sport motors or newer?

I’ve heard of never seen one…

 

[delray]

yes Skipp, they will look like this and carry a part number 36605K. Move the timing from about 20 to 30 degrees advance.

 

[Skipp]

Thanks

 

[Travachu]

Thank you guys for advice. The engine moves me pretty good, gets to about 25mph around my field and 30 on the road. And used to move 250lbs pretty well, or so I've been told. I've outgrown this bike as well, will have to move my seat back... I might put a predator or something similar on it, but not sure. Maybe even a The Clinton engine I have and put the 3.5 on my blown up bike. Awhile back I thought I read about something on the web about a racing version of the h35, but must've been the h50. Thanks again. Have a wonderful rest of your day you guys. Ill be sure to stick around.