2002 Viper doesn't launch like it a rocket

Wizard

Wizard

Member
Joined
Jan 31, 2013
Messages
98
Age
56
Location
Traverse City, Michigan
2002 Viper with only 4100 miles, stock air box setup, venting, carbs, jetting, reeds, EVERYTHING!, great compression, power valves clean and adjusted, servo working as it should; TPS passes all the tests, no codes; all systems go...almost! And it's done this since I bought it early last season with 3200 miles.

Been trying to fix this over the past couple weeks and it's officially driving me crazy! Dealt with it most of the season up until now because it's not the sled I ride and wifey literally doesn't even notice it because other than this small glitch it's an awesome trail sled in every way; idles like a dream, easing on the throttle in a normal manner seems totally normal, runs up to 100 MPH with ease, but again, it's driving me crazy and I want to correct it. Here's the issue:

Think drag racing; sitting still at idle and pin it to full throttle...instantly bogs and dies if you keep the throttle pinned. The Viper I ride (again, not this one) and both of my SRX700s pull up the skis in this exact same scenario. What the hell is different? I've set the carbs of the 2 Vipers up the same; chokes all turn all the way off, float levels set, needles are clipped in 4th position with washers on top, fuel screws currently at 2 but I've tried 1-1/2, 2-1/2 and even 3 turns out with very little change. The last clue to the mystery is that putting it at half choke causes it to idle like crap as it should, but that's the only thing I've found that eliminates the bog and allows it to launch like a true blue beast.

Has anyone ever seen this? Is there ANYthing besides carburation that I should be looking closer at; TPS, PVs, other? If not, then what should I be doing to the carbs to work this out? Thanks!
 
Did you verify the jets? Swap carb racks from good viper, that will tell if it in the carbs.
 
Yeah, pilots cleaned at the beginning of the season and the clutch never even grabs the belt; this hesitation is immediate, like hitting the kill switch. Squeezing the throttle hard shuts it right down, though don't get me wrong, it's not electrical...TORS is bypassed and when I let back off the throttle it stays running fine. I was hoping not to get to the point of swapping racks, but alas, that's likely my best way to be sure where the problem is. Thanks!
 
Ok, if jets are clean, you'r not getting fueldelivery to carb's properly. So you need to go over your hole fuelsystem, filter in tank, pump, vacumpipe to engine, fuelscreens on floatvalves etc.
 
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having the choke half way on and it gets better is telling you its lean..., so youd look for a airleak or something causing it to take in more air then fuel. Such as carb boots, crankseal, etc. a lot of times these can be found easily with a can of carb clean. Let sled and idle and spray around each carb boot and watch for a change in idle speed rpm, youll hear it change. same for spraying crankseal behind clutch. the mag side one is a bit harder to detect as you cant really spray at that one well. if the boots and such check out its in the carb rack, either incorrect pilot jet size or the idle fuel passage in one of the carbs is obstructed.
 
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