help with checking bearings

[10sball]

ok so my old motor started knocking and i never did figure out why so I just assumed it was a bearing in the lower end.. Well I bought another 400 with a lot of nice suspension stuff and a bottom end for cheap so i was gonna use that bottom end.

Well yesterday i was messing with the old cam chain tensioner and every 8 out of 10 tries I could get it to collapse by pushing down on it.. hmm that might have made some noise.

MY QUESTION: aside from trying to move the rod up and down what else do I need to check to look for a bad bearing or anything else that could have made the knocking/clacking

[10sball]

anyone?

[PaRedneckRiders]

you should not be able to collapse the cam chain tensioner put by pushing on it, you should have to take out the bolt in the middle and turn the screw part inside it with a small srewdriver then it you put a bolt in that it will hold in untill you put the tensioner in then you take the bolt out and put in the little screw that should be there.

[10sball]

yes i know this that's why i am asking what in the bottom end could cause a knock... my motor was knocking/clacking and we couldn't pinpoint it and I didn't have the money to go into the bottom end. So the other day i was trying to get a swingarm bolt out of a different 400 and started playing with my old tensioner and noticed i could collapse it which i realized could cause the clacking noise..

so basically I'm trying to justify that my old bottom end is good before i just blame the noise on the tensioner and build a motor on a bottom end with a knock.

all i need to know is how to check the bearings in the bottom end other than wiggling the rod. thanks a lot for the answer though

[matts27]

Rod is up/down & side to side. If the motor is still together you could have used the screwdriver trick and listened for the area with the knock.

Could be something in the case/ trans/ shift fork. Any lower spinning part. Did it go away at different throttle speeds? Under load? In gear/neutral? Try to remember where the noise was most pronounced, that'll point you in the direction most likely.

[10sball]

gear position didn't change it, it didn't ease into the noise it just started making it nothing led up to it it happened when it was idleing, it wasn't a pronounced knock more of a clack, and it was pretty much heard everywhere and extremely loud... could a tensioner be that loud?

[10sball]

I FORGOT, this is prolly really important, when it was clacking the kid i got it from came over and put a head gasket on thinking that might be it.

When we started it it was kinda better for like 30 seconds just ticking every once in a while then started clacking again like it was before this is why I'm thinking I can blame the tensioner since he removed it and reset it in the process.. I think I'll put it in and try it if it makes noise oh well I'll use the other one.

[matts27]

If the tensioner was that shot the chain would be wacking the valve cover and you'd have marks under the cover. The chain would have to be way streched too. Are the guides clean? Sounds like another problem either with a lifter, valve or component. Somethings gotta be seriously wrong and pretty apparent. Meaning something has to be wacking the case or hitting the head/valve, something. Is this motor all stock?

[10sball]

no not even close to stock, hot rod stock length rod/crank, 12.5:1, ported head with web cam 479.. I'll check the valve cover later. the guides had some grooving is that what you mean? I watched a video of someone who said there chain was stretched and it was almost the same distinct clack, just mine was louder. which I imagine more cylinder pressure would be more violent on the chain so that would make sense right?

[10sball]

ok, so I was looking at the bottom end and i notice it was kinda grabbing every revolution of the clutch/flywheel. all the springs and plates are out. but every turn the whole assembly just locks. BUT if you try to pull outward on the basket it spins freely, it also looks slightly bent when watching it turn from the side.. Anyone heard of anything like this? it also feel somewhat sloppy. Is it supposed to be real tight or do i need a bearing too?

[10sball]

one of the 3 screws had worked it's way out and got jammes between the cam chain guide and the basket... wow