Stupid cam chain tensioners

[PaRedneckRiders]

For those of you who havent seen it yet here it is, This is what made me think i had a blown shock.

I kept getting oil blowing all over the shock and the back of my motor, i tried 3 different rear shocks and then i looked a little closer.
This is what i found
a cracked cam chain tensioner and thats what happened when i pulled it out it just all fell apart. Along with i found out the bottom hole for the tensioner is stripped out.
It doesnt look like its cracked the hole way through, and its not there but its cracked where the bolt goes also so when you tighten it down it starts to leak but most of the problem had to be the bottom hole because after letting it warm up and i ran it for a bit i could see through the bottom of the tensioner where it should be against the cylinder.
I know they were not stripped when i put the motor back together so IDK WTF happened but its stripped now and leaks oil like a SOB
THIS IS JUST FREAKING GREAT :mad:
http://i815.photobucket.com/albums/zz72/PaRedneckRiders/400ex%20rebuild/2011-03-1395145358.jpg
http://i815.photobucket.com/albums/zz72/PaRedneckRiders/400ex%20rebuild/2011-03-1395145337.jpg

[PaRedneckRiders]

and im not sure what all the parts are to the tensioner but please please tell me that its all there because i dont want to have to pull the side case and try and dig around for missing parts of a cam chain tensioner.

[CJM]

Looks like everything. Id buy a new stock one, odd how it cracked like that.

[hocman123]

u might be missing the snap ring that holds all that stuff in and if it busted like that i would say somehow the snapring must have broke

[PaRedneckRiders]

Is that the snap ring up above the rest of the stuff??
id so its really bent up and looks pretty bad, mayb thats what caused it but i sort of plan on buying a manual one.
Not sure yet i just something to get it done before this weekend.

But im going to talk to my buddy to see if he has an automatic one i can buy off him.
The cam chain should not be stretched at least lets hope not because its a pretty new chain.
I want to get a crf one anyways so if it is no big deal other than it prob wont be done for this weekend.

[CJM]

I cant even get the 2nd pic to fully load for whatever reason.

But your tensioner didnt fail due to a stretched chain. It cracked due to metal fatigue or a flaw in the casting (more likely).

Id say you just got a bum unit.

[AtvKid4Eva]

Wow. Never seen one crack like that! Just replace with an OEM one like stated above.

[PaRedneckRiders]

Here is a link to the second picture mayb this will work
http://i815.photobucket.com/albums/zz72/PaRedneckRiders/400ex%20rebuild/2011-03-1395145337.jpg

But ya im going to see if my buddy has one i can get.
What im worried about is trying to drill and retap the bottom hole.
Do you think i should even try it with the motor in? i was thinking about pulling the motor and doing it but not sure yet i think if a pull the subframe off or at least the rear shock and air box and carb i along with the head pipe i think i could get it.

[CJM]

2nd pic still giving me fits and Im not even at home,im using my schools pooter.

Anyways I would just remove the cylinder, your gonna need a headgasket but at least it insures you dont get any shavings inside the engine. I wouldnt drill it inside the frame unless its a blind hole (it ends and doesnt go all the way in if its a blind hole). If its a thru hole your gonna get shavings and thats very bad. If it indeed blind hole put a rag in the actual cam tensioner hole too.

Then take a drill and a tap and tap it for 1/4" allen head style bolts. You should be able to find everything you need at lowes or home depot. If you want to keep it metric you could try cleaning up the threads if they arent shot or maybe going to 7mm. 1/4" and 7mm is VERY close, but the brightside i you will find 1/4" much easier than 7mm.

[PaRedneckRiders]

Ya they are blind holes, they dont go all the way through so thats why i figured maybe i would be able to do it still in frame.
If i had another head gasket around id just pull the cylinder but as long as i get something that will hold up for at least a weekend i will be happy.

[CJM]

yea, I couldnt remember tbh.

Id try leavingit in the frame, maybe remove subframe and shock and exhaust.

Like I said tho, try 1/4" first and if you gotta do more, go 7mm. Not much room for error tho, I think 8mm might be the largest size you can get away with.

[PaRedneckRiders]

I went and took a look at it and i was wrong the bolts do go the hole way through so this is what it looks like now.
Im either going to take it to tech tomorrow and retap it or take it to my buddies shop Wednesday.

http://i815.photobucket.com/albums/zz72/PaRedneckRiders/400ex%20rebuild/0314111714.jpg

[CJM]

Good luck with it!

[PaRedneckRiders]

Thanks i decided ill just take it to tech drill it tap it and get a bolt while im there.

[PaRedneckRiders]

Took my cylinder to tech today, we ran a 1/4 drill bit through it to clean it up then used a helicoil. So its good as new
Now i just need my new tensioner, and it should be here Thursday or Friday.

[CJM]

Hope the helicoil holds, it should if it was done right. I havent had good luck with them tho :( but that was on an exhaust stud on the EX so IDK.

[PaRedneckRiders]

I haven't had many problems with them before but we well see, hopefully it does.

[CJM]

I think its just the area I tried to use one in,. Also, learned the other day I was also snugging them up way to tight.

[2001400exrida]

I had nightmares with my tensioner bolts. One of them snapped off, I had to have a weld put on the remaining part of the bolt and then it backed out.

My tensioner failed and my cam chain would only bend in one direction, the guides were narled too.

but my tensioner was just stuck it didn't move at all when i took it out, the spring was shot.