Just bought a 780 Viper

Yamaha_Chuck

Yamaha_Chuck

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Joined
Mar 18, 2011
Messages
62
Age
41
Location
Keswick Ridge, N.B.
Hello everyone, I'm new to this forum and just bought an '04 Viper S with a 780 Hauck engine. The sled has 6500 miles on it but looks more like 650...it's mint! I had it out yesterday for the first time and was really impressed with it, especially when it smoked my buddies 800 rev...he was really confused (didn't tell him about the 780 kit). My question is this, how reliable is the motor going to be with all of those miles on it? The pistons were replaced 1200 miles ago but it has had the 780 kit in it most of its life. The crank is original. Also, how much H.P. would it be making? My guess is about 170.
 

make sure to heat them up properly before u go for a blast and your gonna love the sled
 
like mod said. proper warm up a must with a 780 or it won't last long. as far as hp it depends on the whole setup. carbs,pipes,heads, etc... but if its stock carbs and pipes your guessing quite a bit on the high side. post us the whole setup
 
Haucks 780 kits are crap, w/o added attention from the porter/tuner. I'm assuming you'll have the aaen pipes on there as well. My guess is no more than 150-155hp. Hauck is too conservative w/the compression and they don't port much after cylinder boring. There was a fellow on here that gave his dyno specs of his 780 viper and it was 149.8hp or so. But w/o knowing what size carbs you have, what compression ratio, etc.
 
huh, with haucks low power are they any more reliable?? wondering if it makes a decent trail setup??
 
This is what is done to the motor:

Trail ported 780 cylinders
Hauck tripple pipes
Venom heads
V Force reeds
Re jetted carbs
Digatron EGT kit
#4 clutch kit

And yes, I always warm it up to 120 deg. before taking off
 
Yamaha_Chuck said:
This is what is done to the motor:

Trail ported 780 cylinders
Hauck tripple pipes
Venom heads
V Force reeds
Re jetted carbs
Digatron EGT kit
#4 clutch kit

And yes, I always warm it up to 120 deg. before taking off
Click to expand...

if hauck "trail ported" your cylinders, then they really did nothing more, than leave a mark on the port roofs, from the carbide burr. also, hauck pipes are either cpr's, or aaens. post a pic of them pipes and we can tell you what you have. their venom heads are ok, if you have someone make you a dome, w/the correct squish clearance and volume, as theirs are extrememly conservative. theirs are usually designed for 87 octane. their clutch kits aren't the best either, but even after all my "negative" sounding reply, you can still have a blast on the sled, but will have more fun when the sled if built by a better builder.
 
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