Juha Tanila made a screamer firing-order Gamma, and this is what it sounds like:
https://www.youtube.com/watch?v=QemlcbuFuMY
I have never met Juha.
However... I feel like this guy is my long-lost, hyper creative, mad genius brother. You have to understand that beyond the RG, Juha builds turbo bikes, tractors, houses, overpowered electric fuel drums, pretty much anything.
AND HE DOES IT ALL HIMSELF!
"I think I'll make a stroked, big-bore Gamma engine with a 90 degree firing order... and he just goes and does it. IN HIS OWN SHOP!!
Here's a sound clip of the screamer, one of the first times it ran
(this will download an mp4 audio clip)
Incredible. Sometimes a man of few words, sometimes a man of many, many incomprehensible words, Juha Tanila is a truly fearless fabricator.
He posted many details of this build as he went along, however I have lost most of my archived mail as I went from computer to computer.
And then... once it was built... he took it to the strip and ran 10.50s.
So if you have links or info about this insane-sounding engine, send it to me and I'll put it up here!
I will add a little info up front- with the 90 degree firing spacing (instead of two pistons every 180, like a normal Gamma) we all thought the engine would sound like an inline-4 with the high-pitched howl. This turned out to be false. Juha said it sounded like a "normal" Gamma when it had standard pipes on it. However, he built a 4-into-1 exhaust system for it, by making his own, hydroformed, center-exit pipes. Those outlets went into a common collector so it truly had 4 exhausts coming from one pipe.
With this setup, the sound was out of this world!! Check out the video at the top of this page to hear an initial test.
A few quotes along the way:
"My screamer is 59 bore x 54.7 stroke, = 5980cc.
First with RG150 pistons from Michael Oliver which I fried by fuel starvation and stupid belly exiting stingers, that shit just doesn't work.
I tried that with 3 engines now and fucked up every one. Now my engine has pistons from Mark Dent, CR125?
There have been guys doing long stroke cranks over the years, has anybody succeeded to make them, and make them work? Took me 12 years, I wish I never started that.
Funny, just sitting here with teenager who was born when I started building the screamer engine. I said, 'you both look promising'
:D
"Finally got it started. Sounds super crispy and most of all - no water
leaks!! Yes! Now a million of this and thats.
I did have a major gasoline spill, looks like those cheap Japanese
needle valves aren't good straight out of the box.
There is slight burr in the needle seat around the relief which causes needles to stuck easily. I smoothened the seats and now they seem to work.
Most likely they will work better when they wear out a bit but be warned.
I was on right side of bike holding up a can of gasoline and operating fuel
pump (it work from 30% throttle up) and eyeballing carb on right
side only.
Both left side carbs were pissing straight trough!!
Dyno time soon if nothing terrible turns up."
At the strip, this bike ran like this:
1/4 mile, 10.597 @ 213,53 km/h (133.4 mph)
Legendary!
I can be contacted at rg500delta@mac.com
RG500 screamer - Juha
