I just did the carb slide/throttle bracket mod and the suggested rejet from Raptor 80 racing. The quad starts/runs/idles well; but I have the following problems which I can not seem to correct:

1) If my kids hit the throttle wide open from a dead stop the quad will bog down and stall. They have to ease into the throttle before going all the way. Once the quad is moving there are no issues with WOT. The problem is only from a dead stop with WOT. I have read that others have this issue but I have found no fix on the forums......what can be done for this ?

2) Switching from N to Drive will always stall the quad no matter how warm it is. Is this normal ? I would love to be able to have it warm up in N and then switch to drive without it stalling out.

Thanks

 

Stalling from N to D sounds like a pilot jet problem. Could be the same problem for WOT from dead stop. The Pilot is the first to engage, but if you're already moving, pilot circuit is pretty much bypassed.

If the pilot dumps too much fuel at once, the engine is only idling and the load will kill it. Moving, the RPM are up, the throttle is in play, so the pilot is already being used, and the carb has transitioned to the needle and main jets.

Throttle dictates what circuit of the carb you're in rather than RPM, so any WOT from no throttle will first, and always, engage the pilot jet, than VERY quickly engage the needle and main jets, dumping lots of fuel in a very short time into the engine.

Good rule of thumb is to think in thirds. Roughly the pilot is the first 1/3 of throttle, needle is second 1/3, than main jet is the rest. Once a circuit is passed, it is still being used. The other jets "suplement" the ones before it.

 

Thanks, I have to check what size pilot I put in. Don't remeber which one I used.

If the stock is a 15 then I put a 12.5 if the stock was a 12.5 then I used the 15. Raptor 80 racing gave me a new pilot jet and told me to use the new jet if I had problems. I probally should have left the stock pilot jet in, but I wanted to do the job once and was hoping it worked correctly the first time.

Should I put back the stock pilot jet or go with something else ? Would backing out the pilot jet in the carb make any difference ? If so what are the effects of turning the pilot jet out from fully seated ?

Thanks for the help. If I can get rid of my two problems I will be very happy with the quads new upgrades. I want to reslove all these issues
before I get the new CDI box.

 

Backing out a jet a turn or two won't do anything. A jet is either in or out. You jsut screw them all the way in. The bigger the jet number, the more fuel flow. I'd imagine the stock was a 12.5 and the 15 was the new one. You could put the stock back in. 15 is most probably the next size up. I'd run the stock first to see if that improves things.

Also, does the Raptor "surge" when you first give it gas? Or if you barely give it gas to move slowly does it feel like it's jerking or bucking some?

 

No, it actually runs really well. It idles great and starts with no problem on the choke.

Also while riding feels good to as long as you take it easy with the throttle before you take off. Once you are moving you can slam it open and it responds well.

When you stop from full throttle and cost to a stop it stays running and will not stall. Before I took the carb apart and cleaned it it would never stay running. From what you told me above I bet all my problems were a clogged pilot jet.......would not staying running unless on choke, would not idle correctly....etc

The only issue is the stall from stop to WOT and stall from N to D on take off. Before the mods the quad always did not like full throttle from stop but it would never die it would just start out slow then move on.

You have been a good help so far thanks for the input. I have learned alot...........If this info was not a help let me know. I really hope I can get to the bottom of this.

 

It sounds like the stock jet was good, just dirty.

Try going back to the stock pilot. Leave the other jets the way they are. I bet that solves the problem.

Did you adjust the mixture screw (air/fuel) any? Leave the setting were it is, but if the stock jet seems like it wants to stall, but not as bad as the bigger one, try turning your mix a little leaner, maybe 1/4 turn at a time.

 

Ok, I will put back the stock pilot jet and see what happens. I did mess with the air/fuel mixture screw a little bit that did not make any difference
with the current pilot jet.

This weekend I will put back the stock pilot jet and see how things go ! Should I put back the stock main jet also ? According to what you said this really should have no effect since the quad is not having issues once the rpms are high enough for the extra fuel. I am thinking that the new main jet is needed since the slide mod is allowing more air into the system. Don't want to run too lean. Am I correct...this is what Raptor 80 recommend and those guys were right on the money with everything else they told me to do.

I will give you an update once I get the pilot jet changed.

Thanks for everything.

 

I'd only change out the pilot, leave everything else the same.

 

sianod,

I am presently working on this same issue with our Raptor 50 (runs great but WOT from idle stalls the machine). I have had the 50 stock pilot jet 15 and the 80 stock pilot jet 12.5 both do the same thing (although I have found the 12.5 pilot seems to work a little better). I recently tried to adjust the slider needle valve up a notch but that did not work. I am not sure if it is a lean or rich condition. but I am going to try doing the WOT from idle and examine the spark plug to see if it is excessively wet from fuel or dry this will tell if it rich or lean. I have also noticed that if you WOT it and it starts to stall and you drop the throttle back to 1/4 the engine will recover and start to increase in RPM. my son has gotten good at feathering in the throttle to allow the RPMs to pick up before WOT and it seemed to work well.

 

This is my exact problem ! My kids have also gotten good at playing with the throttle to avoid a stall. Does your quad also stall
if you move from N to D ? If it was not for these issue I would be very happy with the new increase in power.

I checked my notes last night and I am running the 12.5 pilot jet. The stock was a 15. After what you said I am not going to bother taking out the 12.5 which I am running now then.

I have found out that many people have this issue but I have yet found someone who has fixed this problem. There has to be an answer/solution to this problem. You are right..........I have no idea if I am running lean or rich. From what I learned from the above posts it has to be releated to the pilot jet.

The quad never did this before the mods; so it must be because of the slide mod. I bet the carb was never designed for the extra air flow and that is why we all have this issue.

Please keep me in the loop on your progress........I will do the same. I am going to try and give the guys at raptor 80 racing a call and see what they say....