GX140 Hemi build

[karl]

I think those $12 ebay special tillotsons hate ethanol.

Even with stabilizer and running dry for storage, I have had 3 refuse to run right again after sitting (on 3 different engines). Cleaning did not help, Carb kit costs as much as the carb.

Yesterday I could not get the snowbike running (victim #3 )

I only have one new carb left! One a season I guess haha.

Also, I think we are confused. I put a gx160 head on my 212 hemi.

 

[bob58o]

So what is that cog ratio? Something like 3 crank turns per blower turn?
And are you planning on using both those carbs? Why not just one bigger carb? Seems easier.

 

[65ShelbyClone]

So what is that cog ratio? Something like 3 crank turns per blower turn?
And are you planning on using both those carbs? Why not just one bigger carb? Seems easier.

Pulley ratio is 16/50 for a 3.125 underdrive, so about 160cc/rev. I was planning to use a multi-rib (serpentine) drive since the pulleys are easy to make on a lathe vs. a mill, but stumbled across toothy parts with the right ratio.

No, no dual carbs. One will probably get used only for gasoline/NA testing purposes and the other will go on a different engine or on the pile.

 

[65ShelbyClone]

The flywheel fits with a little cutting on the taper.

Incidentally, I also ordered a monstrously large 210lb/hr fuel injector. What could that be for?

 

[65ShelbyClone]

I guess the injectors come in pairs. Now I have two 210lb/hr injectors capable of supporting 550hp on gasoline...because I'd be disappointed with any less than 3800hp/L from a 145cc engine.

They are actually intended for CNG engines and aren't rated for liquid fuel, but are supposedly flex fuel compatible. I wonder if they're compatible with other things..

 

[65ShelbyClone]

Rainy afternoons aren't common here, but when they happen, it's on the weekend. Off to the shop to make an air filter adapter/velocity stack thing out of white Delrin from the scraps bin.

 

[NewbCarter]

Is there any particular reason you are using a "pumper" (diaphragm) style carburetor ?

Looks like a tillotson HL series to me .

 

[65ShelbyClone]

It can be tuned without taking anything apart, so partly for convenience and partly because I have never used one before. It's supposed to be a copy of an HL-324 with a 20.5mm venturi and 25mm throttle bore.

 

[65ShelbyClone]

I still have to port match it and do maybe a few other things, but that's as far as it's along right now. The big round flanges at either end are staying because I think they will be useful later.

 

[Flyinhillbilly]

It's actually the larger 500. Believe me, I still think about it using it. It would be kind of like this:

I used to race at the same track as this guy. That’s a train blower they scrounged up. They actually started the car with that on it. Never made a pass, but they started it.
That car is fast in it’s normal trim with a much smaller blower.

 

[65ShelbyClone]

Header mostly done except for blasting and paint. What do you all think? Vintage white, BBQ black, or something else?

Zoom zoom.

 

[J.S.@SMS]

I think that it would look good the same color as the valve cover.

 

[landuse]

It's looking badass!!

 

[bob58o]

I agree black like the valve cover.

 

[KartFab]

Have you started it up yet? Almost looks like you will be able to soon.

 

[65ShelbyClone]

I still have to make a coil bracket and one-off starter cup before it will be ready to fire. It's mocked-up with stock parts here to get some dimensions.

And I painted the zoomie black.

 

[65ShelbyClone]

Yesterday I got the starter cup finished, today the magneto bracket done and mounted. The only thing really left is to set the timing, check fluids, and see if it'll pop on gas....and I think it will.


Decades ago this is what racers used in their fuelers. Mine came in today for the more serious juice:

 

[mckutzy]

What kinda plug is that??? almost looks like an aviation or from a rotary engine???

 

[65ShelbyClone]

The closest modern plug is a C55R.

https://ecat.championpowersports.eu/index.php/motorcycle/spark-plugs/C55R

 

[65ShelbyClone]

After beating the tar out of my arm last week, I'm thinking that the magneto is suspect. Spark strength has become erratic and the engine doesn't want to stay lit. No change in air gap and you'll notice no kill switch, so it wasn't that either. I've had problems with these weed wacker ignitions on weed wackers. The eBay Tillotson clone is also junk, so this part of the experiment was fun, but over.


There's one thing I have have had excellent results with, and that's the combination of an inductive coil, 12v power, and a microcontroller. Different engine;