I recently did a few modifications to my 93 300ex. I added a 14 tooth sprocket and a DG exhaust first and everything worked fine. Then I installed a K&N airfilter and jet kit and removed the lid from my airbox. it is jetted to 128. Now when I get past about half throttle in 3rd and 4th gear the engine begins to cut out badly like when you acidently forget to turn your choke off and run the engine too hard. It also cuts out in 1st and 2nd gear but I have to give it considerably more gas in those gears than in the higher ones. My question is how do I fix this problem, I am almost certain I jetted it all correctly, but am not positive. COuld I maybe need a new rev limiter? thanks for any suggestions you may give me. and if it is the rev limiter, does anyone have any suggestions on the best place to get one?

 

It is the DG pipe. I have one on mine and it usta do the same thing same with my friends. I fixed when i got my intake and exhaust ported out. It just vanished. i was told by a couple of people that it is the rev limiter. but i am not sure that will fix it.
I run a 130 main jet.

 

First things first check the plug to see if your jetting is on.Run the quad n any gear 3/4 to full throttle for a few hundred yards then pull in clutch and kill engine without letting it idle.Let engine cool and pull plug if its black its too rich.Just for ****s and giggles i would put the box lid back on and put the stock main jet back in and see if it runs ok.You may have too big a jet for your mods or elevation.It won't cost anything to put the jet in and you can atleast eliminate it from the equation.You may just need to drop 2 or 3 jet sizes.From my experience cutting out in the upper rpm band usually is to fat a jet.I may be wrong though.Its still cheaper than porting or replacing exhaust.

 

By the way how do you like the addition of the 14 t sprocket?Have you changed tire sizes or do you run stock?

scott

 

I like the 14 tooth sprocket, I didn't really cut out much of the bottom end, and this is before when I just had the pipe, I run mudsharks on the back of my bike (they were there when I bought the bike) on dirt and Sand Skate II in the dunes. I dont remember the measurements but the mud sharks sit quite a bit lower than stock and are a bit wider. The sprocket seems to work well, I ride quite a bit in the dunes so I dont usually drop below second gear unless its one of the steeper hills but most of the dunes in Waynoka, if you hit them fast enough you can make it too the top without dropping into first. I wouldnt recomend the sproket if you just want to ride wheelies all day but I grew kind of tired of that and you can still do it with the sproket it just takes a tiny bit more body english. Thanks for the tips about the jetting. One question, if the pipe worked fine before the airfilter and jetting chances are it wouldnt effect anything afterwards, am I correct?

 

I had a very simular problem with my 95 300ex. It was completly stock. But it had sat for awhile before i bought it. So i assumed it was the carb. I took the carb off and had it cleaned and look over real well. They had said it looked great and could see nothing wrong.. I was then told to check my CDI box, i think that is your rev limiter, correct me if i am wrong. A friend of mine has a 300ex, so i swapped CDI boxes and it ran great !! So i went and bought a CDI box. it was used from a 99 300ex. Not real used if you ask me !! No problems since. Email me if you would like to now the source of the CDI box.

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Exer_95....Jason....95' Honda 300ex

 

What did you say was the altitude you run this bike at?

Well if you will it really helps!

I'm just gonna venture a swag though and say you should be running closer to a 132.

 

I got it running well now, I dropped the jetting down to 118, and the plug game out tan, so im guessing thats about right. Thanks for everyones help