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DeadBattery

TRX400EX wont start but cranks

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I recently rebuilt my top end, and I started my bike up for the first time, and there was a valve tick, so I readjusted the valves, and did that a couple times, and now it just won't start, I think it might be my starter but I'm not good at diagnosing it. But when I jump it from the solenoid, since I'm waiting for a new one, it will crank somewhat slow and get hot, so I'm not sure if I need to replace it or not.

Edited by DeadBattery

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Welcome to the forums. When you say its getting hot. What part is getting hot? It does sound to me like your starter is on its way out. Cranking slow can be an indicator of that. Saying the battery is fully charged.

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The whole starter gets hot, and my battery had around 12.6 volts at the time, and I've replaced everything I could think of

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Ok what i would do to start is take the plug out of the side cover and turn the engine over by hand with the 17mm bolt. Make sure you only turn it counter clockwise. Make sure it turns freely. You should have some compression to push through but it shouldnt be really hard to turn a full revolution. The starter can get hot for a few reasons. Engine not turning over smoothly or the electric motor is getting worn out. We want to be sure its not engine binding up.

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Yeah, I've been doing that and all I feel is compression, since I've been taking off, and putting back on the head numerous times to see if ther problem might be timing, but I don't feel any binding at all.

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Ok good. Thats good news. The starter is gunna just be tired then. You can pull them apart and rebuild them. But honestly i would just get one off ebay from db electrical. Stay away from the super cheap china junk ones. They dont last.

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Alright, thanks I'll most likely get a cheap one for now to see if that's the problem, and if it is, once that one goes bad I will get a better one.

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In my experiance the db electrical one is maybe 20 dollars more than a china cheap-o. But they are the ones everyone swears by. And i have one on my quad and its been on it for about 4 years. Zero issues.

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Alright, I'll get one, but I think the one I have right now is a niche, and I think it has a warranty, but I'll see.

 

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I did some more tests to see if it was the problem and it does turn out to be the starter, so it will arrive here in a week or less

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On 5/7/2023 at 8:53 PM, SlammedRanger said:

Sounds good! Keep us posted! We are always happy to help!

I replaced the starter, and it still didn't start, but it should be able to run 93 after I put a big bore or do I still have to run 87

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Is the new starter doing the same identical thing? You can try taking the battery and putting jumper cables on it and touch a ground and a positive to the side post on the starter. If it turns over smooth then you only have wiring, the solenoid, and the start switch in between the two. I would personally never run 87 in any atv or dirtbike. 93 is minimum. Probably even says that in the factory service manual. How high of compression you plan to go will decide what fuel you use. (10:1-11:1) 93. (12:1-13:1) 100 or 110

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No, the old one would barely crank, this one cranks fast, and I jump it from the solenoid for right now, since I am waiting for it to get running first, but for some reason when I connect the ground wire from the rectifier to the battery, it will turn over. And it does fire, but I'm guessing it might be the cdi box, since I read somewhere you need an oem one, since I have a Chinese one, that came with the wiring harness. I might look more into it, and if it does seem to be that I most likely will buy an oem one, and if that doesn't work I might try and take it to a shop and see if they can figure out what it is. And I've been running 87 in it, since I first got it, but I figured since I was putting a bore in it to run a higher octance.

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