2002 piped viper blew up!!

bufalobob said:
viper w/ bender pipes:
gut air box
leave vent tubes in air box
needle - middle ( stock )
pilots - 60 accross
mains - 165 accross - mimimum - to 167.5
the air box not gutted is tooo restrictive. needs to be gutted for proper airflow to allow the pipes to make max power.
bob
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Bob:
Would the restrictive nature of the Viper airbox[even gutted] not create too much negative pressure on the float bowls[causing a overly lean condition] for having the vent tubes "in the box"?

I'm thinking that, with that large of a main jets, the nozzles[needle jets] would have to be larger as well to flow enough fuel flow for what the main jet sizes require???
 
Re :Gutted Airbox on SRXs

The 1998 + 1999 SRX stock airboxes had divider plates and a shelf
The 2000, 2001,+ 2002 SRX stock airboxes had NO divider plates and a shelf

So... even Yamaha thought it was a good idea to at least partially "GUT" the SRX airboxes.
 
there are 3 areas of possible different atmospheric pressures under the hood. one is under the motor, one is between the hood & heads & the other is in the air box. the reason to run the vent tubes to the air box is to even out the signal between the float bowls & carb flange air intake. we learned this years ago w/ the '92 vmx4's ( see dyno tech research archieves ).
the i.d. of the nozzle is a lot bigger than the i.d. of a 165 main.
 
bufalobob said:
the reason to run the vent tubes to the air box is to even out the signal between the float bowls & carb flange air intake. we learned this years ago w/ the '92 vmx4's ( see dyno tech research archieves ).
the i.d. of the nozzle is a lot bigger than the i.d. of a 165 main.
Click to expand...

Bob
I was a subscriber to Dyno Tech back then...that was the biggest "Racer's Edge" you could have back then! [ I built an extremely competive Decker Piped 02 650 improve stocker right from the pages!]

After that venting artical I moved all my sleds vents[that had outside the hood air intake] into the box.

From the info I have my thoughts are: the Viper has only P-8 needle jets, with the needles eating up some of the inside diameter they just seem a little restrictive...I run Q-8s on my airbox vented SRX.

Thanks for the info! Bob
 
mikuni nozzles are incrementally progressive to correspond to the changing clip positions of the needle. going from a p-8 to a q-8 is a huge increase. once the throttle is wide open the needle is out of the nozzle & not restricting fuel flow. if a lean spot is found then one may be better served to find a needle w/ a different taper to add fuel at that particular throttle position. changing needle taper maintains throttle crispness & eliminates fouling plugs in mid-range. when the '94 vmax600 came out it did not respond well to porting & pipes ( lean mid range ). we tried a lot of different things including huge nozzles which cured the melt downs but left the mid range soggy & 6 mpg. bruce ( now pioneer performance ) created a needle w/ a different taper which allowed us to go up only one nozzle size & retain fuel mileage & throttle crispness & no plug fouling.
bob
 
I've made the decision to put the stock pipe back on the sled and ride it stock.I like the pipes but just want to ride the sled and ride it hard and not have to worry of another piston problem.Thanks for all the help.I will have the pipes for sale on the classified side if anyone is interested.After Christmas if not sold there ebay bound Thanks again guys
 
sideshowBob said:
Re :Gutted Airbox on SRXs

The 1998 + 1999 SRX stock airboxes had divider plates and a shelf
The 2000, 2001,+ 2002 SRX stock airboxes had NO divider plates and a shelf

So... even Yamaha thought it was a good idea to at least partially "GUT" the SRX airboxes.
Click to expand...
Your saying that the 2000 and up had no divider in there, My airbox has the big piece on the bottom one plate in the middle with 3 holes and the a top piece with 3 holes 1 inch wide by 3" long then the foam that clips on the main bottom part, does that sound right

Sorry for hyjacking but just checking on the airbox I have is right
 
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:) I leave my SRX stock too, Yamaha did a pretty good job. Its fast enough for the trails and I'm not drag racing it :)

But. I bet if you restored everything to stock, put the pipes on and jet according to the manufacture of the pipes, you would be good.

Just my 2 cents. I'll shut up now.
 
wifesviper said:
I've made the decision to put the stock pipe back on the sled and ride it stock.I like the pipes but just want to ride the sled and ride it hard and not have to worry of another piston problem.Thanks for all the help.I will have the pipes for sale on the classified side if anyone is interested.After Christmas if not sold there ebay bound Thanks again guys
Click to expand...
Good decision ma man !!!


i'd rather be riding.....then riding the fastest,,stock rocks!!! ;)!
 
My Bender piped 04 Viper i ran 170 mains and 55 pilots, needles in stock position, two turns on the idle screws, three one inch holes in the top of the air box. The dcs would come on on a really cold day. Otherwise it ran great. 2000 hard miles and no problems running the pipes. I think you burnt it down from too lean on the mains.
 
justaviper said:
My Bender piped 04 Viper i ran 170 mains and 55 pilots, needles in stock position, two turns on the idle screws, three one inch holes in the top of the air box. The dcs would come on on a really cold day. Otherwise it ran great. 2000 hard miles and no problems running the pipes. I think you burnt it down from too lean on the mains.
Click to expand...

exactly. an improperly jetted sled, will burn down, regardless of stock pipe/s or aftermarket pipes. i would leave the benders on there and just rejet like some of us told you already. it can be reliable. you just need to take the time to set it up correctly. my '02 viper has aaen pipes on it. they have been on there for 3 yrs and no issues what so ever.....but i took the time to jet it/setup it up correctly.
 
I put the motor back together the other night and I'm going to run the pipes (peer pressure)I going to put the air box to stock and run 170 mains and 52.5 pilots for now. Dealer had no 55 pilots in stock.From what I;ve read on here 170's are real save and will end up with 167.5's .Any other ideas would be great Thanks
 
mopar1rules said:
exactly. an improperly jetted sled, will burn down, regardless of stock pipe/s or aftermarket pipes. i would leave the benders on there and just rejet like some of us told you already. it can be reliable. you just need to take the time to set it up correctly. my '02 viper has aaen pipes on it. they have been on there for 3 yrs and no issues what so ever.....but i took the time to jet it/setup it up correctly.
Click to expand...
I put the air box back to stock and left the 162.5 mains in for now and left the vent unplugged from the air box.I have the 170 mains but they seem like a really high jump from 162.5 and alot of people on here are venting the carbs to the atmosphere and running alot smaller mains
 
162.5 mains on carbs vented to atmosphere is plenty rich. you'll most likely drop back down to 157.5's or so. 52.5 mains are plenty too. 50's would have been fine. leave carbs vented to the atmosphere. put needles at 3.5 position or 4.0 position.
 
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