300ex cutting out half way through rpm range???

[darwood300ex]

I just traded for a 300ex not to long ago and I have never owned one before. when I first rode it it seemed to have an extremely low rev limit. well i finally got the tank of gas that was already in it ran through and Got it on a long strait away and realized if i just kept into the throttle at what seemed to be the rev limit it would break past the cutting out and take off to acheive the full rpm range. My problem is that it is cutting out right in the middle of the rpm range. I am thinking maybe the carb needs to be cleaned or something along those lines??? Anyone ever had this happen before? I would appreciate any input as I am fairly new to quads. I have installed a k & n and gutted the stock silencer and rejetted from a 122 to a 130 and moved the needle down 1 notch but the bike was doin this in bone stock condition. Although it never got past the cutting out point in stock form.

[dirtdawg]

check the fuel filter if u haven't. maybe a bad rev limiter. bruce300ex is partin out but check the oil filter and your idle speed. they run like **** if the idle isn't good. bad plug is a lso a possiblity. cleaning the carb woulldn't be a bad idea either. just do a little tuneup and check the stupid ****. then go from there.

[darwood300ex]

I'm not sure where the fuel filter is??? do these even have one? the line from the gas tank goes directly into the carb... idles perfect though, no roughness or anything. the limiter should be fine because its not actually hitting the limiter its just cutting out and I THOUGHT it was the limiter. quad doesn't smoke or do anything funny except for tick a little like the valves need adjusting. oil filter could be a possibility cause the guy before me prob never changed it, just the oil I bet. does this sound like a fuel problem though?? keep in mind, before it cuts out it runs like a champ, tons of tourqe, and after I push it past cutting out the horse power really takes over and is smooth as butter, pulls strong.

[jandjracing]

The reverse and neutral saftey switches can cause what you are expirencing. The wires go to them right behind your brake pedal. When the switches have a bad ground to them (located in the engine case), they route your revs through the reverse inhibitor. Try grounding those two wires out to the frame and see if it helps. You can just expose a little bare wire with a knife and run another wire from them to a bolt. Grounding them temporarily might cause your starting in gear, etc to act funny for now, but you will know if that is the problem.

[darwood300ex]

dude......that is a very real possibility because my neautral and reverse lights flicker when they are on IF they will even come on at all... whats the best way to fix this??? professionally?

[jandjracing]

Originally posted by darwood300ex
dude......that is a very real possibility because my neautral and reverse lights flicker when they are on IF they will even come on at all... whats the best way to fix this??? professionally?

I built mine for national MX. I got rid of half of my wiring, so I cut the wires going to the switches and grounded them to the frame. When I split the cases this winter, I will take the switches out completely. I guess if I were you, I would ground them out similar to how I did and then replace the switches whenever you need to pull your motor apart. That is if the revese or neutral saftey features are important to you. Unplug the wires going to your switches, tie them together, and ground them. I bet that is your problem.

[darwood300ex]

awesome dude... I will try that tomorrow evening or maybe even tonight after the tot falls asleep since it might not take but 5 minutes since I have a set of shearing linesmen pliers. so there is a plug on the exterior of the case that the wires plug into? just un-plug them, cut the wires, ground them, then secure them? is this correct. And if I do this it will only start in neutral? will I lose reverse also? thanks for all the help man

[darwood300ex]

Issue Solved!!!!!!!!! worked perfectly after I grounded these two wires! thanks broseph.

[fox945]

Just had a buddy that started having the same problem with his. I was just wondering if this would be the same for a 97' 300ex.

[darwood300ex]

ya it will fix his problem if his lights are flickering or he has a short in the line somewhere or the switches are bad. my switches are bad inside the case. it really frees up things too. you dont have to be in neutral to start anymore and the reverse limiter is gone now. the safety stuff should only be there for first timers or kids. what I did was cut the wires right before the plug, sheared the wire, connected a round like bolt style electrical splice end and put the bolt that holds the steel plate through it for reverse and neutral and bolted back up to the original holes. very simple. maybe 10 minutes.

[fox945]

Tried the grounding out trick but still didn't work. Maybe if I can tell you the whole story behind it somebody can tell what happened.

He bought an aftermarket rev inhibiter off of ebay(first mistake) and he also bought and put in an Iridium spark plug. Well he put both in the same day but it wouldn't even try to start with the new rev inhibiter, so we figured it was dead and put his old one back in. He rode it around for about 3 mins and it was like it lost all power all of a sudden and now it acts like it has a really low rev limit, barely higher than reverse rev limit. I'm thinking it's his rev inhibiter but he thinks the new one he installed messed his CDI up. If I'm not mistaken if the CDI was messed up it wouldn't fire at all would it? If anybody has any feedback it would be appreciated.

[darwood300ex]

Well thats exactly what mine was doing but the grounding worked for me. My neutral light stays on now and my reverse light stays off. There are some forums on here about completely bypassing the reverse inhibiter and removing it but I havent got into that. try a search for it. he might also have a short. was it doing this before he tried the new reverse inhibiter?

[fox945]

It was running perfect before he tried the new rev inhibiter. The new one didn't seem to work at all so we put the old on back on and it ran fine for about 3 mins and then it started this problem.

I went over all of the wires and plugs on this thing to make sure nothing was loose. It has me pretty darn confused.

I'll also look on the forums for the bypass you were talking about.