Viper Head Mods

duckyd, ya need a mega power water rail, which are hard to find, the srx heads will bolt on.


Viper2007, you must have the carbs vented to the atmosphere??, usually the jetting is around 152.5-155 like that, but you still need at least 47.5-50 pilots and needles jacked up, have ya peeked inside to see what pilots and needles settings you have? I would guess without seeing the engine,other 2 pistons they were also having some detonation issues possibly from lean jetting or low octane fuel, look for slight sandblasted around edges of piston or small little nicks. The other possibility would be a liitle drink of water/snow in the gas and thru the carbs, doesnt matter which cylinder then.
 

So how is it with the Hauck pipes the jetting is so lean compaired to the Bender pipes? 152.5-155/47.5-50 VS 165-167.5/55? What are the stock Viper jets?
 
the carb venting, if you leave the carbs vented to airbox the jetting will be around 162.5 mains in a cpr viper, if you vent them to the atmosphere your jet size will drop on mains but it doesnt change the mileage...... the poor fuel mileage comes from the fat pilot jets and high needle settings needed to make the aftermarket pipe work!
 
the Mistake i made was after cleaning the carbs when i bought the sled... knowing nothing about piped yamaha's, was that i plugged that vent line into the air box

both other cylinders were running a little on the rich side (wet good color plugs) and the PTO was burning funny since i started it up that morning, a greyish dry color... I changed the plug and let it warm up it then seemed to be running okay until a WOT run on the lake and that was when the PTO popped, exhaust side melted down on the piston and screwed the cylinder.

I still have to take my carbs apart and find out the needle settings etc., how exactly do I know the needle is on the third setting?

could very well be water though never checked the condition of the tank when I bought it.
 
I've been running mine with Bender pipes, Opticool gasket, rear heat exchanger and stock head for over 1000 miles now with zero problems. Yes, I had to make some adjustments, but not due to the stock head. Is it running to it's potential right now that way? No, nut it runs great and pulls hard. I'm debating the same thing right now. Should I get the mod or go with a new head all together? Either way I amdefinately getting it done, most likely this summer.
 
Just MO but before spending the $125-$150 for a head mod, I would look into a used A/M head. Cause for the extra $100 or so you'll a head with more cooling cap. and possibly a better cooling design but again this is MO.
 
ExpertXViper said:
Just MO but before spending the $125-$150 for a head mod, I would look into a used A/M head. Cause for the extra $100 or so you'll a head with more cooling cap. and possibly a better cooling design but again this is MO.
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Actually I think it is a lot closer to 250 - 300 bux more for the aftermarket head? Unless a guy can find a nice used one. I will not give up the DCS and like I said in an earlier post Bender says their pipes will not work with DCS without a head mod. So that leads me to believe that without the DCS and without the head mod there is detonation. It may be slight but it is there bad enough that the DCS detects it. Eventually I would think that would lead to failure.

It seems to me that for everyone I hear that has a piped Viper that runs great there is another that has a piped Viper that has burned down. From what I have read part of it is error on the side of performance. Part of it deviations in the manufacturing process within design tolerances?
 
Like I said in my post ("A USED A/M HEAD")


Ive seen the Water Rail Design Peak Heads that are DCS compatible go for $300 on ebay. Just have to keep a eye open for them. If your talking Mega Power Heads then yes except to pay more.
 
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