Britton Carter

98 honda fourtrax 300 2x4 engine noise?

16 posts in this topic

Hey guys, I just bought a 98 fourtrax that had an engine noise that was loud. I've had one of these quads before and it wasn't loud at all. The noise is coming from the engine, but I can't locate where. Ive replaced the timing chain, tensioner is working properly, replaced the top end, adjusted the valves properly, rebuilt the carb, lapped the valves, replaced the valve seats, checked the cam with a micrometer, but I haven't fixed the noise. The noise stays constant through all gears and all acceleration, nothing makes it worse or better. I've spent lots and lots of hours trying to fix this problem and have hit a dead end. Any suggestions or ideas to try would be greatly appreciated. Thanks!!!!!!!!

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Ignition timing set correctly etc? Maybe to far advanced? Cannot tell whether coming from low end or top?

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No, can't locate where its coming from, when I replaced the timing chain I was very detail oriented when making sure the engine was at TDC, and I made sure the two marks on the timing chain sprocket were level with the cylinder head, just like the manual suggests, is there something else with the timing I could check? Thank toy for your response Josh

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Did you pull tyhe stator cover off? Flywheel and pickup coil contact makes a loud ticking that corresponds with rpm

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Wish I could tell you for sure but not positive if you have lined everything up at tdc should be fine. Have you also checked valve lash? Maybe they are a little to loose. I'll do a little research and see what I can do to help out

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I haven't taken anything off the left side of the engine,  maybe it's there somewhere,  i used a feeler guage to set the valve clearance, so i think they're right

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Valves are probably good then, they would make a rattle sound if they were out of spec, I had a rod back off on my harley rattled like crazy.

Really the only thing on the left the would make noise is that pickup contact and the starter no disengaging.

If it's on the right could be something bent internally or clutch stuck open but I haven't really seen that myself.

If you decide to pull off the side cover a trick is to tip it on its side so you don't have to drain the oil. I usually lean it on something so it the gas doesn't pour out and the oil can't get in the combustion chamber. Make sure you pull the plug in case any oil does get in. When im done I usually crank it with the plug out to makes sure.

 

That works with left and right cases too!

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I think I need to let people hear it, outta so odd of a noise and again I dont know where to go from here

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On 7/15/2017 at 11:48 PM, Britton Carter said:

I think I need to let people hear it, outta so odd of a noise and again I dont know where to go from here

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You can upload an audio file or video file if needed, as an attachment. 😁 You might be able to do it via your tapatalk app you are using.

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Would be great if uploaded the audio definitely give us a better idea what we nay be dealing with.

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I didn't realize I could do that,  ill be putting a video on here tomorrow when I get home from the fire station,  thank you guys for all your help!!

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It's definitely on the left side. What I would do is pull that left cover off and check the pickup coil. Sounds like my big bear last week after swapping one out. Can't use a feeler gauge on mine because the pickup and stator are mounted to the cover not case so i pit it on, ran it, had a very similar ticking, pulled it back off. Then loosened pickup screws pushed it back then reinstalled. She ran perfect all day mudding Saturday.

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Thank you for the input,  ill definitely check that first,  I also noticed today a lack of power when pulling a trailer,  I didn't replace the friction discs when i had the right side case off,  and im regretting it now

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 Ok,  I feel like an idiot, but this is my first major work on this quad,  how do I check the pick up coil?

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Everybody starts somewhere, first I would drain the gas from the tank and tip it on its side like said a few posts ago. Just find something to sort of lay it on when you do so it doesn't fully lay on its side but keeps the oil in (unless you want to change the oil, in that case just drain and don't tip it). 

In the next steps it's imperative that you take a lot of pictures to help out when you reassemble. Also take cardboard and draw the covers on it and poke holes where the screw are for a templet for the starter cover and left side cover. The bolts will be different lengths.

1. You have to pull your starter gear cover (the black one) forst and remove the starter gears that turn the flywheel. (Pictures!)

2. Remove the bolts that hold the left cover and as you pull it off it is magnetized so it will be tough. Along with that it's probably stuck on by the gasket and will require prying it off. Most  atv covers have tabs that you can pry against to pull it off if not pry against the starter mount. Try not to stick a screwdriver in there and pry on the gasket surface. As you pull it off be mindful that the shift shaft will come out when you pull the cover. 

3. The pickup coil is in the cover. Two screws hold it in but first inspect the metal tab that faces the flywheel. If it's nicked or scared by any means you can loosen the screw push it back and tighten or replace if really worn. Only move it a little.

4. While the cover is open inspect everything else in there.

5. Reassemble!

You will probably need a new gasket and it might be worth looking at a new stator and pickup since you are opening it up. But that's up to you.

Check the oil level before starting.

I hope this helps you out some!

 

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