fresh top end...whats wrong??

[Exrider434]

I just put a new piston and rings in my 400, and just got it back together today. i started it and it has this horrendous tick at idle, and does not go away at higher rpms, it blows huge amounts of white smoke as well, what would i have done wrong?

[sab24711]

sorry to tell you but that sounds like rings are a problem.

if it was valve seals (another reason for white smoke) it would go away after warm/hot engine but all the way through the rpm......humm......rings, also check your valves clearances they might be off. that might be the tick. did you just put the rings on or did you space the gaps out properly?

[Exrider434]

everything up top is brand new, new piston rings, valve seals, you name it its got it. and yes i spaced out the ring gaps, each ring end gap was properly measured and was well within specs.

I read in another post that the cam chain tensioner may be the problem? well i checked that with no luck. is it possible that i messed up the cam chain guides during the reassembly and they arent allowing the tensioner to actually tension the chain?

The noise it makes sounds like this,

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that was posted by another member on here who said his problem was the cam chain, so thats what im assuming it is......

Time to tear it all apart againnnnn.... :ermm:

[ryanhood1983]

Bump. mine is doing the exact same thing.. wtf

[Exrider434]

heres somethin wierd... ithe first time i tried to fire it up nothin happened... so i checked over everything and realized i never checked valve clearances.

So i checked em and every single valve was wayyy too tight. I'm talking like .002 in and .001in tight. so i adjusted them to the proper measurements and thats when the noise began.

It fired right up first time i started it but with the nasty tick, slap, whatever kind of noise you want to call it.

What woulda made the valves get that tight??

[ryanhood1983]

So yours runs ok now.. I just rechecked the timing and the valves. everything seems good. Still making that horrible sound tho

[matt14c]

Are you sure that you were going counterclockwise when setting your tdc? I made the same mistake when putting mine back together but I knew that they couldnt be that far outta wack so when I checked the manual on how to do them right again I figured that out. When I was doing it wrong my were the same way. Way too tight! Also go around a couple times and with the lifter caps off try to wiggl them with your fingers. Should move slightly. Then adjust your lifter clearence. .004 intake and .005 exhaust.

Take that little philips screw out of your cam chain tensioner and using a tiny straight blade screwdriver wind up your cam chain tensioner. then unscrew it the opposite way or let it go to make sure that it isnt stuck and actually working. When you put your guides back in you sure that the removable one clipped in well and didnt come lose?

[KillerKoatings]

subscribing, mine makes the exact same noise. Checked the valves and they were perfect. I want to see what the fix is so I can get rid of the annoying tick.

[Exrider434]

Originally posted by ryanhood1983
So yours runs ok now.. I just rechecked the timing and the valves. everything seems good. Still making that horrible sound tho

No it still runs like garbage, i gotta re adjust the valves because there is no way possible they were that far out of adjustment!

I've adjusted valves after a previous rebuild and they were maybe .001 inches off, not .004 inches off, i know i had to have messed something up in there, time to tear her down again in the morning!

Matt14c, i will check into the guide being out of place because that was one of the things that first came to mind when i figured out that the tensioner was still good. And yes i was rotating the motor counter clockwise, but not sure if i adjusted them on the exhaust stroke or compression stroke..... GAhhhhh soo many possibilities, i just want to get this figured out, its been almost a full year since ive ridden it!

Another possibility is the decompression mechanism sticking? I searched around on here a little bit but the noise that makes doesnt seem to be the same noise mine is making.... Oh well, worth a shot i guess!!

And thanks again to everyones suggestions, i will let you guys know when i get it taken care of so i can hopefully help you guys out as well!

[ryanhood1983]

I have been reading the online manual today. It seems I didnt put the tentioner in the correct way, i didnt release it with the home made tool first. could this be the problem?

[mcgrath]

Its probably just because you adjusted them way out of spec. If they were in spec before you did the rebuild and didnt touch the valves they wouldnt be any different after assembly. There is probably way too much valve lash and rattles like crazy. One of my buddies did that to his lawnmower before with the same noisey results.

[Exrider434]

ill give that a shot when i get home, that is very possible considering the valves were extremely tight when i adjusted them.

[Exrider434]

Thank you mcgrath!

Too much valve lash was the cause of my noisy top end, im assuming what i did is adjust the valves on the exhaust stroke, where at proper adjustment the rockers had very little movement...

When i took off the valve covers today to check them on the compression stroke, i had at least a half inch or so of play, i dont even know how it started...

When you check your clearances, MAKE SURE ITS ON THE COMPRESSION STROKE!!!!

Hope this can be of help to any of you other guys out there, it started right up and ran like a champ with no noises!

Time to go give her hellll!

[ryanhood1983]

Mine must be the chain.. ive adjusted the valves to perfection and same result. I went a little too small one time and a little too big of a gap once also and the loud pounding tick/knock remains. If anybody has any other ideas let me know..

I took both the side covers and the valve cover off to inspect today,, everything seems good. I have all the exhaust off now just waiting to tear into it. I really dont want to do that again..

Who's video was that?? Id like to ask em for sure what the deal was

[mcgrath]

Right on, heh glad to help. I know I appreciate all the help I get, and god knows I need it. lol.

[ryanhood1983]

so I ordered a new cam chain yesterday.. hope that does it.

I noticed something new also. when I set it up on tdc 'exactly' the cam does not line up as it should, the marks on the cam gear.. ive moved the chain one link ahead and one link back and the marks are never level with the cly head. Does this mean the chain is streched?

[mcgrath]

Are you sure you are lining up the timing mark for tdc? It is the line with a T beside it. If you are lining up one of the marks before it they will never line up. I belive it is the third notch on the flywheel. If its lined up with the T your timing will line up perfect.

[ryanhood1983]

yea im very sure its lined up right, on the line right next to t. But the cam is always off just a bit, like a half link.

[mcgrath]

Is your tensioner working properly? If so I guess put the new chain on and see if it lines up. Seems odd though. Not sure man, I guess if the chain is stretched far enough it will put it out of time. New chain might fix the problem, I havent had this problem so Im curious too find out.

[ryanhood1983]

well its coming from bikebandit so it will be like a week.. but ya the tentioner is working. I used a lil screwdriver and turned it and it retracted from the chain, when I pulled the driver out it popped back onto the chain. Ill probably take the valve cover off tomorrow and look for something odd. maybe take the head off and have a look around too. I will not ride it making this noise, no way.

It does run great tho, I dont get it..

[ryanhood1983]

Installed a new timing chain today, the old one was streched out so far the tentioner was barley touching it. with the new chain the tentioner is backed out almost all the way. The knocking sound is gone finally!!

And the lines on the cam are level with the cylinder head now, while the crank is on tdc.

Thanks guys

[sab24711]

man i was wrong. i to had also put a new chain on mine cause it jumped off the crank it was so far stretched. my brother and i were beating it up and after he got on the quad for the second time out around the mountain, two seconds later it just died out of power.i also remember the valves sounding louder than the quad when i got off. the tensinor was shot it had no spring to it your finger could have pushed it in.

it happens when you buy a beat up quad the time and the money it takes but hey i think its well worth it when you plan on keeping it.