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The plug does not have to be tight for the engine to run, but if it's not tight enough to prevent leakage, carbon from combustion might fill the threads and lock the plug into the hole. Get it running first and then worry about the plug later.
 

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The plug does not have to be tight for the engine to run, but if it's not tight enough to prevent leakage, carbon from combustion might fill the threads and lock the plug into the hole. Get it running first and then worry about the plug later.
Okay so I’m getting spark now and fixed the stripped stud nut and torque all of the stud nuts to 32 foot pounds and brand new head gasket so no compression leaks out but I’m still getting 90 psi for compression. I’m pretty sure now it don’t start because of low compression what should I do to get it started other than push starting it??
 

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Okay so I’m getting spark now and fixed the stripped stud nut and torque all of the stud nuts to 32 foot pounds and brand new head gasket so no compression leaks out but I’m still getting 90 psi for compression. I’m pretty sure now it don’t start because of low compression what should I do to get it started other than push starting it??
Did you check the compression while holding the throttle wide open? If yes, check the valve clearance and if the valves are right, then push start it - once fired, the compression will probably come up some more.
 

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Did you check the compression while holding the throttle wide open? If yes, check the valve clearance and if the valves are right, then push start it - once fired, the compression will probably come up some more.
Yes I did do that wide open and yes my valve clearance is right but I think I have to push start it like you said and let it warm up and then try to start it with the kill switch it should start. Thanks for the help really appreciate it!
 

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A leaking head gasket will not cause a loss of spark, but it will keep the engine from running. It needs a minimum of about 110 to 120 psi to start - under 100 it would have to be pull or push started
Hello I finally got the bike running it turns on good now and gives good spark and compression thanks a lot for the help!
 

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Now although all the parts you say you installed new are available from Honda, I seriously doubt you spent $835 for parts in your quest to fix the issue. I suspect you bought parts from Amazon or Ebay, so you have a collection of Chinese counterfeit parts on your vehicle, so this complicates matters because instead of troubleshooting the parts that were working prior to the failure, you decided to throw parts at it to see if it would stick.
New member here. Hello all. Glad op got the quad running. Just wanted to point out the above advice for anyone finding tis thread via "no spark" searches. Do not parts swap, especially on electronics. Good parts are too high and the "other" parts are likely bad to begin with. Do not cut wires and jump switches. Go buy a good Fluke multimeter with a min/ max button. (model 110,115,117 are most common range from 100-200 dollars) and study. The meter will last a lifetime of abuse. You can wire your house, diagnose a bad receptacle, fix your car etc etc etc forever. I see them in factory use every day. EVERY electrician I know uses a fluke meter. Find out which part (singular usually) is bad. All the info you could possibly need is online. Download a service manual if you need one and go step by step. People are lucky to have the internet and folks like the above mod.

I own and operate an auto shop. Lately I've taken to more and more atv. I've ridden and worked atv since my first 84 (iirc) moto4. Back before suspension was a thing on quad. Ive owned yamaha since. Never an issue. Dad had an 88 fourtrax 300. I just got it back to running yesterday (no spark.... surprise). I found these threads hunting for a pin out or service manual. But I work on all brands. Honda makes good machines (excluding ES hondamatic models) Worked on them and chainsaw for many years out of my basement. Then built my shop. I believe more money is there to be made on atv than cars actually. People don't question why it took two hours labor to change a 1500 dollar front end in a sxs (thanks polaris) . They do question why it took two hours labor to change a rusted in place 50 dollar wheel bearing assembly on a car.

Parts swapping as we call it is far too common in the auto industry too. Taking off parts without properly diagnosing. Taking off good oe parts and putting on cheap parts store parts. Or worse, Amazon knock off parts. If your going to do that, at least do it one part at a time and if the problem remains... put the good oe part back on. Parts in the atv/sxs world are even more stupid high priced than cars. And with the internet there is no reason to not study up. Back pre internet we did have to do some switch jumping and such. Lol

On cars I've fixed thousands of dollars in damage caused by cheap sensors that most likely replaced parts that weren't bad. Cheap wheel bearings, axles, interior parts, pumps, racks.... go for it. But anything electrical (or a carb) do not.
 
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