Bumblebee400ex

01 Honda 400EX Ticking in top end, HELP!!

11 posts in this topic

Ok so i got a 01 400 ex that I bought on ebay with a bad top end (bent and broken valves, busted piston the head was seriously messed up). So we got a different head(used) it was fine but needed two new valves so we got those and lapped them in then transfered the springs and stuff over to the new head. We also got a big bore kit(new) and different cam (used). Put it all together and it had a tick(sounds like its coming from top end), figured it was timing chain so we bought a new one and replaced it. Well now it does the same thing, constant ticking. Anyone have any idea what it could be. Heres a youtube vid with sound of my quad with the tick. Any input/help would be great!!

[ame=http://www.youtube.com/watch?v=LX4yknIlc_Y]YouTube - ‪400ex knocking?‬‏[/ame]

Thanks

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did u check crankshaft for balance . piston connecting rod.if u newer set up an engine u no way gonna get good engine work .if u wanna spend your time fixing that on the rail when awry one driving thats you choice people doing like this if they wanna sell ,not keeping for them self

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we never did anything with the crankshaft besides check for up and down play and the spec honda gives in the manual, husband used the same big bore brand in his kfx without balancing and everything went together good without issues. I just want to get some opinions so I can drive with my husband before summer is over. If need be he said he will pull the motor apart and put a new wiseco crank in.

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I was thinking, the same, loose valves causing the ticking. Is that howling noise coming from the motor too, that sounds terrible.

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Well my husband did adjust the valves, but i am thinking thats where the sound is coming from. As for the howling, it doesnt make that sound its just the phone we took the vid with that made it sound that bad.

Thanks all for the input so far :-)

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Your problem is in your valves IMO You said you lapped the valves Did you cut new seats for you new valves ? or at least check the seats ? I was always told to cut new seats for new valves !! I would of had the head checked out by a machine shop first ! but I always do all the valves ! And would never us old springs and hardware

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I would have to agree its valves... adjust them and it will go away...

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did you check the cam as well when it comes to engines you should never put used rotating parts in the engine. a slight flatspot worn on the cam would also cause the same noise. it doesnt take much to make a noise like that. you probably would have a hard time noticing a spot to the naked eye. when you put some new parts you should always go complete new. especially cams! I have diagnosed over a 1000 engines from v-8's all the way to garden tillers. pull it apart and put all new in. you will then eliminate the noise IMO. the noise is defenatley top end and i am 99 percent sure that it is either cam or loose valves.

Your friendly neighbourhood mechanic.

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Well my husband did adjust the valves, but i am thinking thats where the sound is coming from. As for the howling, it doesnt make that sound its just the phone we took the vid with that made it sound that bad.

Thanks all for the input so far :-)

400/ex s are bad about ticking mine does it and it completely new check your timming chain tensor when you rebuild a 400 always check ur timming slides and crank gear and replace the timming chain the howling part sounds like the oil pump not pumping enough oil you always need to replace the oil and oil filter at least 4 times a year i change mine every 4 races on a average as many times as 20 and you do deceide to change out the crank go with a welded on i would go with a 4mil hot rod crank with a 460 big bore with a stage 2 cam.these motors genarate a lot of heat and friction so oil changes are a must.

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I know this thread is a little old but does the ticking go away when you give it a little gas? It might be the decompressor. Check your idle speed with a digital tach not your ears.

Sent from my SGH-T959V using Tapatalk

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