Vibration

[CJM]

Something is def wrong with the ol' 400.

I havent been riding much and today I noticed, it would appear that the whole quad is vibrating more than usual.Very much doubt its the frame or loose stuff but Im going to check it out when I get a chance.

What I do think is its in the motor. Topend kinda sounds like the cam is much louder than normal, kinda like its not getting oil. Vibration is constant, neutral, at idle, throttle, moving, etc.

Crank sounds like its going out to me. Last rebuild I flew into a lake and locked it up. I wonder if the crank is slightly bent?

I dont think Ill be cracking apart the engine anytime soon only b/c I rather fix my 450 instead. Still I wonder anyone had the same issue?

[DragonGunner]

Book says vibration could be timing balancer gear bad...could be worn teeth or jumped a tooth....think ya gotta split cases to check though....yikes. I had bad vibration start on by hybrid once, could feel up into my body,,,,it was a loose motor mount....easy fix. What about bad gas....?.....maybe some moisture got in tank....? Change the plug with a new one.......

[CJM]

Yea, Im gonna start simple but IDK for now. If it comes down to it I dont want to split it right now. Not a huge deal since I have someone who would do the whole job for about 100 + parts since I dont have the time. Just dont want to sink cash into it right now.

ETA: I should also not that although the valves have been recently adjusted (and were in spec anyways) that when cold its a pain to start up. Give it gas, it wants to die, wont rev with gas. Kicks over, runs a sec and shuts off. I didnt have this issue last winter either and the carb isnt dirty.

I wonder whats going on inside of it. Ugh, lets see that would make at least 10x I had one of these apart (not all mine tho :devil: )

Guess Im off to do a comp test.

[CJM]

Found the problem. The cam bearing dowel pin was SITTING in there (flywheel side). I dont know how the cam didnt walk itself around or move or whatever. There are no wear marks I can see, no issues other than that dowel pin sitting there.

Story goes: awhile back when reassembling the motor I noticed one of the cam dowel pins was slightly loose. Well, I couldnt get it any tighter-just doesnt happen b/c of the design. I had thought of threading a small bolt in there to hold it but the way it rides on the bearing I dont think its possible.

Some loctite and it seemed fine. Now, understand I have probably ridden an entire season on it this way. Id say it was like october when I noticed more noise than usual and maybe a month or so ago it started to not want to start easily...

Shame I sold that perfectly good head I had laying around. Oh well. I think Ill just loctite it in again but use red this time instead of blue. Only other idea is to build it up slightly with some epoxy...

Edit: upon further inspection the cam gear is not right as well. Marks are upside down. IDK how thats possible unless I did it by accident last time.

[JOHNDOE83]

Check the mounts for the front of the motor by the oil tank.

On my hybrid I noticed Vibe got bad suddenly, when I took it apart to put it on a new frame I discovered the nuts welded to those front mounts had actually come loose from the frame.

I also noticed that there was almost NO weld holding it in place to begin with. When I transfered it to my new frame I got rid of the welded nuts for a better more solid mount.

I actually removed the welded on nuts with a chisle and a hammer, in 3 hits they were OFF!!!.

Since then my 2 stroke cr250 hybrid EX has hardly any vibe at all.

This might not be your issue, but it is a VERY good mod thats better then factory to reduce vibe.

[hondaREX]

So would you say that this is the same vibration you have mentioned in other posts that you initially thought couldve been your piston? You were questioning the Wiseco being the issue? Just curious if you feel better about Wiseco pistons now.

[CJM]

Its hard to say if this is the same vibration. 400ex motors (actually its an XR400 motor originally) arent balanced all that well to begin with and do vibrate some.

Remember a larger piston (88mm in my case) has a larger rotating mass and this you will feel it to some degree. But the cam was walking around quite a bit

Wiseco is ok, but if your gonna go for broke a JE or preferably CP is a better made piston (most run a CP in the honda 450r for this reason). Im sure wiseco is fine tho, used them on alot of builds before no issue.

As for mounts, yea a few were loose but not very much. The cam was walking around as I stated earlier and that cause all sorts of issues. Right now Im waiting for the generous amount of red loctite to dry in there. When I gotta break it all down again some heat from a torch should do the trick.I also think I coulda used RTV with good results, but having no threads means it doesnt have much to hold onto. Im SHOCKED it ran and didnt destroy anything, I must have rode approx 30-40 hours since october when it began to do this and at least 75 hours since I rebuilt it.

What I may wind up doing is if it fails again I think Ill mic the hole so I get an exact match and machine my own dowel pin.

@John:
Ill probably be doing that mod myself sooner or later. Im anxious to fire it up and see wtf is gonna happen at this point. Gotta wait 24hrs for the loctite to dry to be sure tho.

[CJM]

No luck, loctite wouldnt dry even after 18hrs. I gave up and decided to epoxy the hole shut for the pin and Im going to have to carefully shape it so its ever so slightly smaller so the pin fits in good.

[punk rock kiel]

i dont know what said pin does but couldnt you take a sharp chisel and make marks like a knurl? then it should press back in.

[CJM]

It wouldnt matter kiel. my issue is the pin needs to stay put period. The AL is softer than the very hard steel the dowel pins made of. otherwise Id just mushroom it in there or something.

Last time assembling it, there was a knurl in it-wouldnt go in there and it caused knurls in the hole. I smoothed the hole slightly but I guess I took off too much or something. Thats how the problem began. Really, its a dumb design.

Ill just leave like a thin layer of jb weld just tight enough for it to fit better. For such a critical part you would think it should bolt in. Were talking maybe thou of an inch.

[powerbomb400]

Would it be possible to put a spring pin in?

[CJM]

Actually I think I solved it. I epoxied the hole and then drilled it out-making sure to leave a few thou of an inch of expoy in there.

Then I put the pin in and smacked it down with the other end of a punch of a hammer. Suckers in there good.

Now onto problem 2. Timing chain is done. Its kinking-specially at the top part of the chain when I put the gear in. Tried moving it-seeing if it was just that spot but nope. Chains shot. Right now its sitting in there, nothing holding it up and it hasnt fallen in the motor despite me even trying slightly.

RMATV for $27+part cost can have it to me by tomorrow they say. So oh well. That was a CRF chain as well, but it has been approx 3-4 years Id say.

[JACK STRAW]

would bearing retainer work better than red loktite ? we have use Mega Metal Epoxy before on a Mack e6 engine block that was cracked 3/4 of the way around and it held.

[CJM]

I doubt its gonna come out now Jack. But that Epoxy sounds like some good stuff!

Right now its still apart, RMATV has a timing chain coming tomorrow or friday at the latest. But Ill just take the 450 out instead.

[CJM]

New timing chains in, cam dowel pins seem fine. Added some oil and hit the button and it fired right up. Before I had issues with it wanting to start and stay running, not the case now.

Vibration is of course still there cause its a 400ex and Im using a large piston. But its alot less. Damn hotcam is really loud lol.

Otherwise she runs and runs well. Cant kill the old 400ex.

btw, after all these years I decided to look at my clutch basket to check for grooves. Last I had it apart was a year ago and there werent any really. Its now been at least 5 years of very hard riding with 1-2 years of every so often riding. The basket was BARELY grooved. I mean very little. I dont use the clutch to upshift, sometimes due to terrain and my boots I miss 2nd and pop neutral and still it barely had any wear..amazing.

[punk rock kiel]

i sold my 05 400ex that got a vibration cause i researched and found the main bearings were starting to get worn out or so i assumed. it actually vibrated that much it broke all the welds off the lrd exhaust hanger.
it was time for a 450 anyway.

[CJM]

Might be time to do that Kiel. I just cant consciously sell it to anyone I know cause I dont want them coming and wanting their money back.

Either that or buy a 400 engine and slap my topend on it lol. Who knows what Ill do, Im undecided.

[punk rock kiel]

i wasnt trying to be "that" guy selling something but it was a deal with the issue for all the time and money and parts that were on it and it was an 05 on top of that. his mistake was not test riding it (i dont think they could ride clutch in first place) cause he told me to take it up the alley. so i let it warm up, beat it full throttle up and to 4th gear and even loaded it in thier truck.

[CJM]

Ya sounds like thier fault.

I have interest to buy it from someones cousin, but like I said no dice cause I dont want them coming back on me. Used bottom end is only like 500 bucks but meh I rather not bother. IDK for now lets see how it goes. parting it might make me some cash. Real shame is I just fully rebuilt it last winter.

bet I can find a good used bottomend for less than $500 tho.

[CJM]

Just an FYI incase anyone else searches and finds this:

-Vibration is constant, more throttle you give of course more noticeable and worse it is.

-Topend sounds like its not getting oil in the valvetrain, ticks quite loud and all the time.

[punk rock kiel]

mine didnt tick or get louder but was a 426.

[CJM]

I found a thread on another forum about it, they said same issues and it was the crank. tbh the 400 has ALOT of hours on it so it wouldnt surprise me at all.

[punk rock kiel]

that sucks. mine had some hours on it but i was never real hard on it but i did get to the point where i was running out of power. my vibration was that bad in 5th gear wot on the highway, i couldnt put my feet on the pegs or even nerf bars (would have sucked if it blew while down in hatfield mccoy trails)

[CJM]

Yea, mine isnt that bad but its enough that at the end of the day your hands hurt form holding onto the bars.

IDK what Im gonna do. Really wanted to go to HF/McCoy but IDk if its a good idea. One 450r that needs a topend rebuild and a 400 that might blow at any time. Im gonna take the 400 to a friend and see what they say. I will say ever since I rebuilt it with the 426 setup its been this way. However was th vibration before or after I sunk it IDK. I was losing a quart of oil after I sunk and just cleaned it out-thats what drove me to 426.

[jman7290]

When are you going to Hatfield McCoys? We are going in May sometime, can't remember the exact dates!

[CJM]

Originally posted by jman7290
When are you going to Hatfield McCoys? We are going in May sometime, can't remember the exact dates!

I very much doubt I will be going anymore, I planned on taking my 400ex but this problem kinda ruined it for me. My 450 needs some misc stuff and isnt a trail machine by any means.