Viper "flat" feeling after rebuild

kart74

kart74

New member
Joined
Jul 18, 2006
Messages
130
Age
41
Location
New Berlin, WI
So... finally got the viper back together. New piston, all new rings, new reeds, and opticool. Before the rebuild it ran great. Just thought with the pipes I should get the opticool. Well that led to the rest. So today was the first ride. Did a couple heat cycles before riding. Babied it for awhile and noticed at 1/4 to 1/2 throttle it felt flat. Loaded up kinda. I stopped and check plugs and are black. Rode a total of 60 and didnt get better (thought from the extra oil maybe). So nothing changed in carbs but since the rebuild this. Also the dcs came.on a few times in that space. Once past and on the pipe it is great. Actually that's how it feels... very on the pipe or flat. Any ideas?

Carb vent outside of box
47.5 p
150, 152.5, 152.5 m
Screws 2 turn
Needles 3.5
 

well... the opticool gasket is thicker, so, you increased the squish clearance, thus reducing the compression ratio.
 
I have a rear cooler already. Forgot to mention I am running aaen pipes. So would less compression make it rich and I can tune this out? Or is it that much loss of power? I could put the stock gasket back in but thought this would be better...
 
just checked the piston wash and they are basically clean and wet looking. Very little carbon on the intake side, but other wise nothing. So it was pig rich, but not sure why. Wouldnt think the head gasket thinkness would make that much difference? I am going to pull the carbs and check everything again, but they weren't touched during the rebuild.
 
check choke cable adjustment, plungers could be slightly not going back which will make it very rich all the way thru
 
funny you say that. I just was looking and hit the choke lever and it snapped back... could have been it.
 
Rode 130 mile today. Was much better but still rich in the middle. It was also 35 degrees out so hopefully when colder.it will be good. I also came to the conclusion after 130 rough miles that it maybe time to upgrade to a newer sled with suspension! Knees are killing me. Lol
 
Take shocks off and have them charged, night and day difference. Mine were all discharged.
If they look like they have been leaking fluid, they need to be rebuilt.
 
kart74 said:
Rode 130 mile today. Was much better but still rich in the middle. It was also 35 degrees out so hopefully when colder.it will be good. I also came to the conclusion after 130 rough miles that it maybe time to upgrade to a newer sled with suspension! Knees are killing me. Lol
Click to expand...

If its suspension (more likely low sitting position) You can drop a different skid. A LOT of yammi riders do. I went M10, but if I had to do it over I would go scIII, just because between my track and skid I lost 10-15mph on top end.
 
captnviper said:
If its suspension (more likely low sitting position) You can drop a different skid. A LOT of yammi riders do. I went M10, but if I had to do it over I would go scIII, just because between my track and skid I lost 10-15mph on top end.
Click to expand...

My lord, NO WAY am I willing to lose that kind of speed, lol.
Not for any reason! :D:D
 
I was just about to ask if it could simply be the temp is much warmer than when you rode it before rebuild, than you said it was 30 some degrees. My stock sleds will even run rich at those temps without changing jetting.
 
Yes it is most likely the temps yesterday. I have thought about a skid swap but I'm not sure. Will it make it take the bumps like a newer sled? I know it will be better but I feel like it will still be lacking.
 
yes reed stoffers are all in there. So right now i am running 150-152.5-152.5 with 47.5 pilots vented to the atmosphere. I have been reading a bunch and most guys are running the 47.5 pilots with it vented to the box. So should i be dropping that? I looked at wash yesterday, and even after the 130 mile ride it is wet and barely any carbon. Thinking to drop to 147.5-150-150 and 45 pilots?
 
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