SXViperFanatic
New member
I did a bunch of mod's on my sled over the summer (listed at end). Sled has been running great until the last few rides. After a cold start the sled still runs great. After a few miles or so, once things warm up, it starts to "hick-up" when I'm over half throttle which is about 7500rpm to 8500 rpm. You can hear/feel the motor stutter and the tach rapidly drops 500rpm or so and then goes back up. I can still get up to WOT at about 9000rpm - don't know if it's doing it at WOT b/c I haven't had a chance to hold it open very long since it started doing this.
With SLP pipes on the viper, the mag plug cap is basically touching the pipe. I have heat tape on it but it has nearly burned threw and does come unstuck. The plug cap looks good - no melting or anything. It seems like if that cap was going bad and miss-firing that could cause this condition. I would think that it would show across my entire power band but maybe the pipes are causing just the right vibration at those rpms? Anyone else had the mag plug cap go bad on them due to the SLP pipes?
I really don't think it's in the clutch. The carbs would be the other possibility. I cleaned them a few months ago. I would think if it was in the carbs, my entire mid-range would be affected. 1/4 to 1/2 throttle is perfect - 1/2 & up is the problem. If the issue is in the carbs, is it a possibility that only part of my mid-range could be affected? Checked jetting per Mr Vipers recommendations & plugs are a perfect cardboard brown mid & top circuits.
Any suggestions or input is greatly appreciated. The members on this website are fantastic - the info on this forum has helped me tremendously. Sorry for the novel if you've made it this far LOL
2002 SX Viper with 4000 miles
- SLP Triple Pipes
- Speedwerx Perf Head (don't know what domes - off an 02 Viper)
- 165 main jet, 47.5 pilot, needle 1 below center w/ both spacers below,
1-3/4 on fuel screw
- Tempa-flow
- Reed Spacers
- SRX torque limiter
- Rear heat exchanger
- Heel clicker Drag n Flies
- Stock secondary (have a green spring i want to try)
- 1.5 Ripsaw
With SLP pipes on the viper, the mag plug cap is basically touching the pipe. I have heat tape on it but it has nearly burned threw and does come unstuck. The plug cap looks good - no melting or anything. It seems like if that cap was going bad and miss-firing that could cause this condition. I would think that it would show across my entire power band but maybe the pipes are causing just the right vibration at those rpms? Anyone else had the mag plug cap go bad on them due to the SLP pipes?
I really don't think it's in the clutch. The carbs would be the other possibility. I cleaned them a few months ago. I would think if it was in the carbs, my entire mid-range would be affected. 1/4 to 1/2 throttle is perfect - 1/2 & up is the problem. If the issue is in the carbs, is it a possibility that only part of my mid-range could be affected? Checked jetting per Mr Vipers recommendations & plugs are a perfect cardboard brown mid & top circuits.
Any suggestions or input is greatly appreciated. The members on this website are fantastic - the info on this forum has helped me tremendously. Sorry for the novel if you've made it this far LOL
2002 SX Viper with 4000 miles
- SLP Triple Pipes
- Speedwerx Perf Head (don't know what domes - off an 02 Viper)
- 165 main jet, 47.5 pilot, needle 1 below center w/ both spacers below,
1-3/4 on fuel screw
- Tempa-flow
- Reed Spacers
- SRX torque limiter
- Rear heat exchanger
- Heel clicker Drag n Flies
- Stock secondary (have a green spring i want to try)
- 1.5 Ripsaw
sxviperfantastic, does the mag plug look any differnt compared to the other 2 plugs?
usually when a plug boot goes bad they will misfire like you describe, you could easily tell if the plug is a differnt color,and looking at the piston top it will be a little wetter looking. You could always take the cap off and move it to the pto wire and see if the problem follows the cap, they just unscrew off the wire.
take my advice only as a grain of salt, its usually always wrong compared to the experts now...
usually when a plug boot goes bad they will misfire like you describe, you could easily tell if the plug is a differnt color,and looking at the piston top it will be a little wetter looking. You could always take the cap off and move it to the pto wire and see if the problem follows the cap, they just unscrew off the wire.
take my advice only as a grain of salt, its usually always wrong compared to the experts now...
mod-it
Member
That's a good one Mrviper. Don't worry, us "old timers" on here know to pay attention when you post a response to one of our questions.
And I think you're right here, speaking from experience. When I first got SLP's on my sled I had the same issue, the mag side cap was sitting against the pipe. The rubber cap may not look burnt, but I bet that is still the problem. I changed mine to the high heat, hard plastic cap to try to help out this problem, but it actually made it worse. The hard plastic ones would become brittle and end up cracking. What was happening was while riding through bumps the pipe was always grinding against the cap, and it would eventually wallow out the inside of the cap where it "snaps" onto the top of the plug. Pretty soon the cap would be loose enough that it would simply pull right off the plug with no resistance, so when I hit bumps it would jump up off the plug and lose contact.
I ended up putting the rubber cap back on, and added a spring to help hold the pipe away from the cap. I was able to use existing hooks, so I didn't have to add any. I always carry a spare in my coat, but have been running it this way for several years now and have not had to use the spare.
And I think you're right here, speaking from experience. When I first got SLP's on my sled I had the same issue, the mag side cap was sitting against the pipe. The rubber cap may not look burnt, but I bet that is still the problem. I changed mine to the high heat, hard plastic cap to try to help out this problem, but it actually made it worse. The hard plastic ones would become brittle and end up cracking. What was happening was while riding through bumps the pipe was always grinding against the cap, and it would eventually wallow out the inside of the cap where it "snaps" onto the top of the plug. Pretty soon the cap would be loose enough that it would simply pull right off the plug with no resistance, so when I hit bumps it would jump up off the plug and lose contact.
I ended up putting the rubber cap back on, and added a spring to help hold the pipe away from the cap. I was able to use existing hooks, so I didn't have to add any. I always carry a spare in my coat, but have been running it this way for several years now and have not had to use the spare.
super1c
Super Moderator
mrviper700 said:
That couldnt be farther from the truth mrviper. Your knowledge and expertise
are bar none. Its guys like you that keep this site going. Ty and myself are thankfull for sure. You keep us running right!!! Sorry for the thread hyjack but that needed to be said. CCC
mrviper700 said:
Not sure where you got that idea but I assume this was directed at me.
As others have said, your expertise is second to none.
That's all I'll say.
SXViperFanatic
New member
Right on Super1c. I was hoping Mr Viper would share his thoughts & he did so immediately. Unfortunately winter has sucked here in MI this year... there's really not much more snow up at the Mac Bridge then here in Grand Rapids. I need to take it out and run it up until it starts missing, kill it, and more closely examine all 3 plugs & pistons. Hoping we get some snow this weekend to do that - will keep you posted.
Thanks for your input Mod-it. You probably saved me from buying a hi temp cap that would fail too. Great suggestion on adding a spring to pull that pipe away. Even if it's not a bad cap I'm going to add that spring anyways.
Anyone else with SLP's have trouble with the mag plug cap? I'm thinking this is pretty common...
Thanks for your input Mod-it. You probably saved me from buying a hi temp cap that would fail too. Great suggestion on adding a spring to pull that pipe away. Even if it's not a bad cap I'm going to add that spring anyways.
Anyone else with SLP's have trouble with the mag plug cap? I'm thinking this is pretty common...
I think MrViper is right on here and that's where I'd start too. I have a pretty similar set up as your self and my mag plag cap also touches the pipe. I too use heat tape. I've been lucky so far and that plug cap has worn away there but it's integrity has remained intact.mrviper700 said:
So that is where I'd start too. And following Mod-It's advice I'd also just stick with the OEM plug caps. Good advice from both these highly respected gentlemen!!!
Seriously, I'm no mech by any means. But Both MrViper and mod-It are two guys (amongst many others) who's advice is golden -- they know their shiite!
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SXViperFanatic
New member
Now I'm definitely looking for advice. I took it out & killed it when it started missing - holding the throttle in the same spot until stopped. All 3 plugs looked good - no noticeable difference. It was too dark to read piston wash. I replaced all 3 plug caps & plugs. I removed the tempa-flow (i had it off before & it was doing it but wanted to eliminate a factor). I removed the reed spacers. I cleaned my carburetor - still was very clean.
I went out for a ride with the guys the next day (finally got some snow). It's still doing the same thing - it ran good and reliable except for the consistent miss's at 3/4 throttle / 8000 to 8500 rpm. Again, it always runs perfect the first 5 miles or so after sitting.
- could timing cause something like this? Should I be paying attention to timing with the pipes & head mod? I'm not knowledgeable about timing considerations.
- I'm going to go through the clutches but I don't think they are the cause
- Maybe the "ignition boxes" or wires?
- Seems like a wear through on my wiring harness could be a culprit. Don't have any lights on or flashing or anything acting funny electrically. (My TORS is disabled)
I went out for a ride with the guys the next day (finally got some snow). It's still doing the same thing - it ran good and reliable except for the consistent miss's at 3/4 throttle / 8000 to 8500 rpm. Again, it always runs perfect the first 5 miles or so after sitting.
- could timing cause something like this? Should I be paying attention to timing with the pipes & head mod? I'm not knowledgeable about timing considerations.
- I'm going to go through the clutches but I don't think they are the cause
- Maybe the "ignition boxes" or wires?
- Seems like a wear through on my wiring harness could be a culprit. Don't have any lights on or flashing or anything acting funny electrically. (My TORS is disabled)
SXViperFanatic
New member
Also pulled the pipe away from the mag side plug as suggested by mod-it
mopar1rules
Active member
There is a possibility that it is the cdi. I have a spare for sale if interested. Pm me.
I would pull the harness from under the engine if it has not been done and check for rub throughs. Follow JKs links as there are other areas to look at specific to Viper.
Also, you did look at the fuel inlet screens (top hats as SSB calls them) upstream from the needle and seat when you had the carbs off, right?
Also, you did look at the fuel inlet screens (top hats as SSB calls them) upstream from the needle and seat when you had the carbs off, right?
You may want to look at my post. When I pulled my head, it was the mag piston that was wet compared to the other two.
http://www.totallyamaha.net/forums/showthread.php?t=77427
May help you out, and I do have SLP's on my Viper.
http://www.totallyamaha.net/forums/showthread.php?t=77427
May help you out, and I do have SLP's on my Viper.
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Possibly stator related? I had a junk stator that would drop a cyl at high rpms but still ohmed in spec. I chased my tail for a week and finally eliminated all other possibilities, I bought a junk used stator. 
trail viper
New member
my slp viper had the same type of miss along with the gauge cutting out. no rubbed thru wires, took a new stator to fix it. bad stator tested ok. pull those pipes off the plug cap though and watch out for the silencer front edge against the side panel. good luck.
mod-it
Member
02ViperMody44 said:
The only thing that would make me doubt that this was the culprit is if it runs good again after falling on its face without having to give it time to fill the bowls again. From your last post, it sounds like it just has a bog at 3/4 throttle but will get past that and run good again. 02vipermody44 went through hell before finding this, so I'd still recommend checking it.
When my stator started going out I had a mid range bog...when the hand warmers were on. I could make it bog or not bog just by turning the warmers on and off. The low voltage was affecting the performance of the CDI, MrViper said it was because they are on the same circuit. But I also had the common sign of the tach resetting when I hit the brakes or switched between high/low beam. You could try unplugging your headlights and making sure the warmers are off and see if it goes away or not.
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SXViperFanatic
New member
Everyone - Thank you! I've got some ideas now. First one - no I have never cleaned the "Top Hats". I remember reading about them & tried to find info again when I cleaned my carbs last weekend but couldn't (didn't have much time). I am definitely going to do that & I would like to replace my fuel filter for re-assurance.
BlueSRX good suggestion on the stator. Mod-it right on. That was my first thought on ViperMoody's issue (good ref tho & a good read on your post) - mine comes right back... not like an empty fuel bowl. It has never died on me nor have I need to use the choke more than for a cold start. I'm really thinking it might be the stator. My hand warmers have been hit and miss - they will work and then stop working randomly since I bought it last year. This is looking like an electrical issue to me. Either a bad stator or a harness rub through.
I've got some work to do - drag races are Saturday LOL Will keep everyone posted - THANKS AGAIN
BlueSRX good suggestion on the stator. Mod-it right on. That was my first thought on ViperMoody's issue (good ref tho & a good read on your post) - mine comes right back... not like an empty fuel bowl. It has never died on me nor have I need to use the choke more than for a cold start. I'm really thinking it might be the stator. My hand warmers have been hit and miss - they will work and then stop working randomly since I bought it last year. This is looking like an electrical issue to me. Either a bad stator or a harness rub through.
I've got some work to do - drag races are Saturday LOL Will keep everyone posted - THANKS AGAIN