Problem 300ex

[300ex_#387]

Alright well I was at the track yesterday and my 300 is cutting out in the higher gears. Its not backfiring or anything it just hesistates when I keep it at a steady throttle pace. When I'm in 1st or second and give it gas it will just die. I know the jetting is right because I have had it like this for a while and it has worked perfect. Now I bring it home from the track and it wont even start. It started a couple time and I took off but 5 seconds later it just dies. I took the carb off and didnt see any dirt or problems. I was wondering if it could be electrical? Can someone help me out?

[bc_sandlin]

i would try cleaning out the air filter

[300ex mxracer]

its probably your ignition coil. mine did the exact same thing.

[300ex_#387]

Originally posted by bc_sandlin
i would try cleaning out the air filter

Air filter is clean.

[300ex_#387]

Originally posted by 300ex mxracer
its probably your ignition coil. mine did the exact same thing.

Someone told me it could be the ground off the coil, but I checked that and it seemed good. What can do to see if its the coil?

[GPracer2500]

You could get a service manual. It will give you detailed procedures for checking all the electrical components.

[03trx300ex]

make sure to check all the overflow hoses on your carb!!! mine did that and i had mud in one of the two hoses...they might be breather hoses...theres one on the top and bottom of the carb

[300ex mxracer]

Originally posted by 300ex_#387
Someone told me it could be the ground off the coil, but I checked that and it seemed good. What can do to see if its the coil?
take a voltmeter and go over everything.

[300ex_#387]

Ok, well I got it to run. I guess when I took apart the carb to look and see if there was dirt in there I forgot to put the O ring on the cap where I looked at the jets. I took it on a little ride and it ran fine for about 10 minutes then starting cutting out again in the higher gears. I'm just going to take in into the dealer and have them look at it. Thanks for the help guys...

[bwamos]

Probably jsut need a rebuild kit. Rubber probably got hard and isn't sealing well.

[300ex_#387]

Originally posted by bwamos
Probably jsut need a rebuild kit. Rubber probably got hard and isn't sealing well.

What needs rebuilt? The carburator? I can start it up and it will run fine for about 10 minutes then It will start cutting out. It does this everytime I try and ride it. I guess we will find out whats wrong tomorrow...

[DieselBoy]

yeah i think it could be electrical....swap the plug for the heck of it, do a spark test....the problem with these machines when its electrical it can be a number of things, and finding out the actual source can be a real bugger. For the dealer to test it and tell you what it is i think its worth it if your in my situation, anyway.

[300ex_#387]

It wont start again so I did a plug test there is absolutely no spark at all. I'm going to get a new plug tomorrow. Would that plug be the cause of it cutting out though?

[DieselBoy]

Originally posted by 300ex_#387
It wont start again so I did a plug test there is absolutely no spark at all. I'm going to get a new plug tomorrow. Would that plug be the cause of it cutting out though?

believe me it can, how old is the plug? it might be a stator, coil, or CDI going out:ermm: electrical really sucks.

[300ex_#387]

Originally posted by DieselBoy
believe me it can, how old is the plug? it might be a stator, coil, or CDI going out:ermm: electrical really sucks.

Plug is about 3 months old. I'm betting its the coil going out though. If a new plug wont fix it its going into the shop. I hate messing with the electrical crap, I'm afraid I will screw something up.

[DieselBoy]

well for the 30-40 bucks you can replace the coil in about 10 minutes, if that fails, than take it in cause its probably the stator if it's not the coil. i gotta replace my stator.. im very sure that's what it is, but mine wont start at all...

[bwamos]

If you're not getting spark, or it is intermitent, your problem is most likley oxidized connectors.

Clean all connections.

Get out your service manual.. use the electrical schematic for your year (theres a couple different wiring diagrams) and trace back the power going to the CDI. Check and clean those connections. On my '98 it is the Black w/ white stripe wire. Comes in from the wire harnes, up to the handle bars, then down to the CDI, before sending to the coil.

Easy way to tell is to check the voltage with the harness plug in the CDI. If the voltage is like 1-3v then you're probably found the problem. Pull the plug out of the CDI and check it and you'll have 12v again. Classic indicator of an oxidized connection.

[womerk28]

there is something elictral. i got a new plug it still missed really bad. it would idle fine but as soon as i started to ride it it wouild miss really bad. so i got a new wire harness, and it ran fine the next time i rode it and the the cdi box went out and now it runs fine after i got that it ren fine.