HELP!!! Vmax XTC Deluxe 700 bad backfiring

Viper Sniper

Viper Sniper

New member
Joined
Sep 1, 2004
Messages
156
Location
Northern Illinois
I just got done putting a track in this sled and I don't think I ever even disconnected the ignition coils besides don't these 700 Redhead triples have a false ignition on every revolution anyways so if you accidentally switched the wires it would still run right??? It starts and revs high and then backfires so I shut it down switched the center and mag wires and still same thing, I don't think I could've mixed up any other combo of wires because of the way they are linked together. Any ideas or sugggestions?
 
Just thought of someting else...I parted out 4 sleds this fall and one had a full tank of fuel that I dumped into this sleds tank. I thought it looked kinda greenish/yellowish when I was dumping it through the funnel do you think high idle and backfire could be caused by bad gas?
 
It could be water in that bad tank of fuel. I'd get it out of there and try fresh fuel after you clean the carbs. It's not likely it's the coil wires being mixed up. Fuel doesn't stay stable as long as it used to.
 
you could also have a pilot jet partially plugged causing it to back fire. Old used gas is never worth having to pull the carbs again. I always start fresh every fall. Maxdlx
 
I think I did tighten up the slack in the throttle cable too would this cause the TORS to kick in? Does the symptoms sound like something the engine would do when the TORS kicks in. Refresh my memory....does the trottle override system protect the engine and rider in case the throttle gets stuck wide open? This would activate a switch causing the engine to misfire? I was able to check the carbs before I had to leave for work and they were clean. Too add to my frustration I dropped the middle carb pilot jet and the aluminum tube it sets in under the motor. Since this was a trade-in sled I haven't had time to clean it up properly and 7 years of grease oil leaves and dirt have built up a sludge under the motor. I was able to get the pilot jet to roll out towards the PTO side by tipping the sled on it's side. I even removed the exhaust manifold to be able to see under the motor better, but I still can't locate the stupid tube. Three time tipping it on it's side and tapping on the bulkhead pan, I found a bolt, a washer and a zip tie but still no tube. Well I'll take another stab at it tomorrow, but if I can't locate it I'll have to take one out of my Viper I won't be bringing on this trip. Thanks for the help guys!

Tommy
 
Oh yeah I forgot to mention that this sled was running great before I went to install the track so I didn't even touch the carbs which I normally do on every used sled I buy just because the pilots usually get plugged up pretty quickly. And another odd thing was when I removed the gas lines to the carbs to clean the pilot jets fuel just kept coming out of the lines from the fuel pump. I did have the *** end on a track stand but I've never seen the fuel keep flowing like this from the pump. I thought the fuel pump got it's pulse from the crankcase creating a pump effect with a rubber diaphram so without the pulse it shouldn't gravity feed the carbs should it?
 
If the jet is in a tube, that is the main jet. The pilot jet sits way down in the carb body. Be sure to take out the pilot jets and clean them also.
 
Tommy, tommy , tommy, you used old Gas. Man i'm not even that cheap.
doesn't sound like the tors to me, most of the time it will bogg before it backfires when the tors kickes in. Good luck on the jet tube.
 
Bypass the TORS (throttle over ride switch) by plugging the wire harness connection together. and just leave the two that are on the sensor unconnected and try it. It basically short circuits the iginition and creates a misfire. Misfires create unburnt fuel which could ignite in the pipe and backfire. It easy to check and rule out. ITs the switch where the throttle cable goes into the carbs. J
 
Woo-hoo it's fixed!!! Just got done cleaning the pilot jets and yes they are in an aluminum tube in fact the picture on this website in the tech area incorrectly has an arrow pointing at the brass tube, it's inside the aluminum tube right next to it in that pic. Anyways did those and set the float height (I think this was the main culprit) they were off quite a bit, I assume hopefully correctly that you are supposed to bend the tab that the spring clip for the needle seats on right? Since I only have a standard dial indicator I converted 13.5mm to .5314 inch and set them to this height. Siphoned out about 8-9 gallons of fuel and replaced with fresh. I also did what jwiedmayer suggested and bypassed the TORS and it started and ran fine. So since I did all three things at once I'm not sure what actually caused the problem but I eliminated the TORS as the source of the problem since I reconnected it and it still ran fine. I never did find that aluminum tube however so if anyone reading this has an extra and is in the christmas spirit...just kidding I'll order one from the dealer. I just wanted to say thanks to everyone who chipped in on this thread. Now my girlfriend and I can enjoy a nice trip to Gwinn, MI on Sunday. Merry Christmas to all and to all a goodnight :rockon:
 
If you do not hook the tors wires back up the tors switch will be over ridden and your sled will run, but you take the chance that if your carbs or throttle cable freeze up and you start your sled it can take off on you wide open and bing bam BOOM as well as running into some one else or multiple other scenerios. (don't know if that last word is spelled right).
 
Hey that just happened to my friends same year and model sled. He just bought it and what happend was that there were the wrong plugs. so i would check that.
 
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