Trx300ex no spark can someone please help me 62 views and no one can help than what is this website even for

[travb4201 0]

So been working on this bike for almost a year now bored over new stator new Blackbox cdi new pick up new plug new coil new battery almost every thing is new ok I got it to start find out I need to replace the valves and valve guides got to start smoked real bad then it just quit wouldn't spark anymore I'm about ready to give up and take it to the scrap yard I've put almost 2 grand into this bike replacing everything on it i have no clue why it's not sparking I've tried everything Google has to offer I'm honestly sick of messing with it anymore even tho I've put all that money into I'm over with it but I don't want to be over with it I like to try and get it going only rode it a couple of times and this is a list of things I've bought for it 

 

[jeepwm69 7,609]

Most of us here have utility quads, not sport machines, so there's your lack of response.

 

However, looking at what you ordered includes a lot of cheap aftermarket electrical stuff.  Most of that chinese garbage is bad right out of the box, and since you've put a lot of different things on the machine that makes figuring out what is bad a little more difficult.

 

Do you still have the OEM stuff you took off? 

 

Here's the factory service manual.  It will tell you how to troubleshoot and check components using a multimeter, but first thing I'd do is take all the chinese crap back off and put your OEM parts back on, THEN troubleshoot.

 

https://drive.google.com/drive/folders/1NquzFaiKZ8R9T20IMUaexYM2sf1ngw4-

[SlammedRanger 1,556]

Wow thats quite the list. You are 100% sure its spark causing your issue? Have you done a compression test after the rebuild? Did you lap the new valves in? Didnt mention anything about that is why i ask. Im one of the few sport quad guys on here. I will do everything i can to get you dialed bud.

[Fishfiles 20,145]

travb4201 >>>   Welcome to the site !!  >>>>> How did you make out for the hurricane , looks like you were right in it !!

[AKATV 822]

Welcome to the forum!

100% what Jeep said above

I would question all the cheap ebay/Amazon Chinese parts so be careful there

So much better to stick to OEM or used OEM off of ebay, or salvage yard etc

The spark system on these is fairly simple, but requires step by step

troubleshooting to locate the faulty part. 

When you replace it all with cheap china parts you could now have more than one

issue which does not make it easier to troubleshoot

If it had spark with new parts and started several times and then just quit, sounds like one of them failed

Did you originally have a no spark condition before you replaced all the electronic parts?

Let us know what you find when checking as per manual and we can get you sorted out

AKATV

Edited September 5, 2023 by AKATV

[travb4201 0]

Yea I made it ok through the hurricane besides my lean too the roof clasped but no biggie simple to rebuild it just havnt got to it yet Homosassa and crystal river tho my old house in Homosassa got about 2 ft of water everything out there got destroyed I feel bad for them guys but I had the bike running after putting the big bore kit and new valves and valve guides but it would smoke like a freight train than the next day it would crank but not fire I put the plug up to the fins and it would not spark even with a new coil and plug but I just got a new kill switch and wire harness today so ima see if that will fix it it has a brand new black box cdi and I get readings off of it and the other cdi I put a test light on the plug one day and it would light up but it would spark but if the new wire harness don't fix it then I guess ima have to use the multi meter and go through that process it's got a brand new lithium battery so I know that's good all the grounds I sanded down to get a good connection neutral light and reverse light work my headlights work fuse is good but I got to put a transmission line on my truck so if I got time I'll mess with it later and I'll let you guys know whats up and I couldn't afford oem on alot of the stuff so I tried to get what I thought would be good enough for oem ! ain't cheap no more prices on everything is going up besides the pay ! up world we live in now a days it's sad really is but I'll let you guys know 

 

[jeepwm69 7,609]

23 minutes ago, travb4201 said:

Yea I made it ok through the hurricane besides my lean too the roof clasped but no biggie simple to rebuild it just havnt got to it yet Homosassa and crystal river tho my old house in Homosassa got about 2 ft of water everything out there got destroyed I feel bad for them guys but I had the bike running after putting the big bore kit and new valves and valve guides but it would smoke like a freight train than the next day it would crank but not fire I put the plug up to the fins and it would not spark even with a new coil and plug but I just got a new kill switch and wire harness today so ima see if that will fix it it has a brand new black box cdi and I get readings off of it and the other cdi I put a test light on the plug one day and it would light up but it would spark but if the new wire harness don't fix it then I guess ima have to use the multi meter and go through that process it's got a brand new lithium battery so I know that's good all the grounds I sanded down to get a good connection neutral light and reverse light work my headlights work fuse is good but I got to put a transmission line on my truck so if I got time I'll mess with it later and I'll let you guys know whats up and I couldn't afford oem on alot of the stuff so I tried to get what I thought would be good enough for oem ! ain't cheap no more prices on everything is going up besides the pay ! up world we live in now a days it's sad really is but I'll let you guys know 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Yeah stuff is higher than giraffe a$$ and not getting better, but buying used OEM is better than new chyna junk.

 

I normally order used OEM from ebay or PSN.  PSN isn't super cheap anymore, but they stand behind what they sell.  Good sellers on ebay should be the same (check their feedback)

[travb4201 0]

So still no spark even with new harness and new kill switch I don't understand why it lost spark just like that and my black box cdi is brand new cost me 130 something and I don't have money for another one so I guess I don't want to but sell it or it'll sit right where it's at and rot to the ground bc I have no more money or any clue as what is causing it not to spark and its passing me off pretty bad to where I don't even care anymore 

[travb4201 0]

So come to find out my brand new black box cdi died on me for some reason so I guess I got to buy another one put a trx250ex cdi on it and boom beautiful blue spark 

[AKATV 822]

I would contact them since you just bought it

It should be covered under warranty, I would imagine 

I know most electronics generally aren’t, but it’s worth trying/asking, especially if it wasn’t cheap China one for 20 bucks and you paid 130 for it.
I would imagine they should stand behind it.

-AKATV

[SlammedRanger 1,556]

Had the exact same thing happen on my 400ex. Got an aftermarket top of the line cdi box. Ran like crap. Would cut out under any sort of load. Put stock oem one on and it would run perfect. After them sending me a second one then a third. All did the same exact thing. I did eventually get a full refund and sent them all back to them. I would ride around the yard with an inline spark tester on my lap and watch it cutting spark. Never again will i try any aftermarket cdi boxes. All they do is up your rev limiter. Which isnt really all that safe for the motor anyway. See if atv galaxy will refund your money. They have always been very easy to work with for the hundreds of things i have purchased from them lol.

[AKATV 822]

Also I forgot to add

The CDI for this model ATV is still available from Honda and are around 75-85 dollars if I remember correctly?

Is there a reason you went aftermarket?

[shadetree 5,868]

cheap china knock-off c.d.i. this is your main problem.

[travb4201 0]

Blackbox cdi is not cheap China but now when I go to start it it tries to start after the I let me thumb off the starter and I readjust the rockers but still doing the same thing so I'm thinking I got to pull the head back off and re time everything since I've taking the stator and motor apart 50 times I think the timing is off 

[travb4201 0]

So re timed everything and still doing the same thing won't try to start till after I release my thumb off starter button same thing with jumping solenoid when I take screw driver off it'll blup blup then that's it it won't actually fire up and start that's with the old cdi on the bike don't do anything with the Blackbox cdi or my old trx250ex cdi idk what else to do or what but I'm guessing I need another cdi box and I don't have money for that I just recently lost my job over some ! I had no part of so I guess the bike is just going to sit there for awhile even tho I've only rode a few times and I've had it and working on it for over a year now just my luck I guess I can never catch a break 

[AKATV 822]

Have you tried inquiring about a return for the one you purchased that does not work properly?

If  it seems like it’s sparking when you let off the start button, it sounds like a CDI issue

or possibly a weak battery

Have you tried kickstarting it or pull starting it?

I’ve had a few machines with battery and electrical issues that would not electric start, but I could pull start or kickstart them

Also, I remember the old 300 Fourtrax and a few others that would have a CDI issue they would only spark when you let off the button,

It was only a problem on a few models and replacing the CDI fixed it

i’ve seen a few original Honda OEM CDI for your model on eBay for around $40. 

Are you 100% sure when you’re setting your valves and timing that you are on top dead center of the compression stroke?

If you’re not sure, watch your intake valve open and close then continue to rotate until you see the timing mark on the fly wheel and you’ll be good.

It’s very easy to time 180° out if you’re not watching the valves, as you can put the fly wheel top dead center and  match up the timing mark on the exhaust stroke as well

Good luck and let us know what you find out
-AKATV

 

Edited September 9, 2023 by AKATV

[SlammedRanger 1,556]

I dont know for sure as i have never tried to run a quad with a cdi off another type of quad. But the 300ex and 250ex are very different quads. I would imagine there is some difference in the cdi making it not catch and stay running. Have you tried contacting atvgalaxy about the black box having no spark? I really suggest you do. They will probably make it right. I would try to get your money back and get an oem honda 300ex box. When you change so many parts it really makes tracking down the problem very hard. Gotta start with the basics. Spark, fuel, and air(compression). If you have those 3 things and it dont start you then look at timing.

[travb4201 0]

So I get readings from the Blackbox cdi that doesn't give spark bit the old cdi that came off the bike originally does not give readings how come and yes but I bought the Blackbox back in February when I was building the bike and bought everything I tried getting ahold of them but no luck on reply back it's not a kick start and no have not tried to pull start it 

[SlammedRanger 1,556]

6 hours ago, travb4201 said:

So I get readings from the Blackbox cdi that doesn't give spark bit the old cdi that came off the bike originally does not give readings how come and yes but I bought the Blackbox back in February when I was building the bike and bought everything I tried getting ahold of them but no luck on reply back it's not a kick start and no have not tried to pull start it 

Ok first off i just removed the 6 miles of dead space at the end of all your posts. If you could please for my sanity stop doing that. 

 

On to your issue. What readings are you talking about? Resistance readings or voltage readings? I have always found testing a cdi box very hit and miss. As all it takes is one capacitor to be bad internally and now you dont get readings anywhere. Aside from destroying the box to get into it to see the leaking caps it is really a change it with a known good one part to test it properly. That has always been my experiance. Also my experiance has always been all aftermarket ones are junk. I have had dynatechs brand new out of box not work at all. Along with almost all other brands cause weird issues. Have alway went back to stock cdi boxes and had no issue anymore. If your 250ex cdi has spark but wont run. Black box has no spark at all. I would have to say get an oem 300ex one and fire that thing up. Logic says its gunna work. The 250ex one probably wont run because the 250ex is a vastly different quad. If it was a 250x not ex that would be different. But a 250ex is essentially a utility quad with sport quad plastics. Built on the platform of the recon250. Were talking shaft drive. Not even chain drive. Im not at all shocked that box wont allow it to actually run. My .02