inner clutch hub threads stripped

[BLUDGEONER]

Thanks mate. I'll check and adjust the valve clearances tomorrow after work and see how it is then.
Ran and ticked over fine after starting earlier - only ran it for about a minute though, as still no water/coolant in there at the moment. Will change the oil once more before trying it with water in the system

 

[BLUDGEONER]

Oh dear......

Well, my broadband has been off since wednesday afternoon when some halfwit dug up a cable near my home, so I've been unable to share my latest development with you all.....
I adjusted the valve clearances as per Husabutts great post - they were a bit tight. Started 5th kick after that and seemd run/tick over fine - apart from the fact that it was smoking fairly heavily (white smoke). Heard a sharp "tink" kind of sound from engine area - while I was looking at the smoke emerging from the exhaust. Looked down - it was still running ok at this point - saw smoke here too, so immediately hit the kill switch.
Discovered this.......WTF have I done???

 

[tourist]

Oh man Let's hope this is something that can be welded up quick and fixed. Please keep the posts coming for the public benefit

 

[BLUDGEONER]

Will do - can't help but think this may develop into a full rebuild thread....

 

[ned37]

you didn't tighten the adjusting nut properly (or at all).
you've got to find the nut and any flotsam from the impact in the engine and clean it out. hopefully, it stopped immediately after it happened and the crap won't have gone far.
the top can be welded.

 

[BLUDGEONER]

Valve clearance adjusting nut? Definitely torqued them all to 11Nm and double checked them all. I've left it completely alone since this happened as I wanted to hear all opinions/advice before going back in!
Cheers.

 

[ned37]

well, the nut is the most common (right, froggy?, wherever you are). second most common is the autodecomp stop bolt in the cam gear. whatever it is , you have to pull the cam and clutch covers.

 

[pollo]

Sorry to see the outcome with this Bludgeoner.
For what it's worth. I removed the clutch on my 650 to fix that same kick start issue before.
And with the lack of my understanding put it back together bumping 3 teeth off of
the timing marks.
It started, but ran rough and I shut it down quick enough knowing I messed up.
I got that timing mark schematic, removed the clutch and lined it back up.
Everything is fine.
Hope you can get the pieces out of there and it welded up.

pollo

 

[Taffy]

yep the locking nut AND the reason it came off is because 12Nm isn't enough BECAUSE the people before you overstretched the threads AND because the threads are way too loose so 12Nm isn't going to be enough.

as Ned says, that is what it is AND it can be welded. we do them all the time for customers. In the old engines there is a "competition" (sic) to see who can wipe out the most letters in G-R-E-B-A-S-U-H.

leave the "races to the aces" fella.

regards

Taffy

 

[pollo]

I had overtightened my tappet nut several times on my 05 650 from new. Until I learned the proper torque. I then started torqueing 11+ nm. Good thing I didn't loose it. But an interesting note. While torqueing the tappet screw wanted to turn with the nut. Whereas on my other 2 650s that I have always torqued properly the screw remains stable while torqueing.
Maybe it's a sign to help someone not to lose the nut.
pollo

 

[BLUDGEONER]

Thanks for the advice - I'll have a look in there at the weekend. Looking back - they were nipped up tight when I first undid them to adjust...
How quickly can they work themselves loose? I had it running less than 2 minutes. for future reference, how much is everyone torquing them up to?

 

[BLUDGEONER]

The auto decomp is definitely the culprit - broken up. The real worry here is that there is no sign of the retaining bolt or nut.......

I never touched any of this (though obviously should have....), and unfortunately have no idea if the retaining bolt was there when I adjusted the valve clearances. I'm assuming it can't have been left out by a previous owner otherwise this would surely have happened earlier?

By the way - shouldn't that camshaft bearing in pic 2 be rubber sealed? I know that's the least of my worries

 

[ned37]

i can't see your pics (and don't have photobucket account), so i have to guess you mean the stop bolt for the autodecomp is gone. some people remove the stop bolt to keep it from falling out and causing a problem.
as far as the cam bearings are concerned, some people replaced them with open bearings. AND sometimes it's the bearing that disintegrates and knocks the seal off when one or more of the balls escapes and causes a problem. look closely at them. i believe they have 9 balls.

 

[BLUDGEONER]

Thanks Ned - that goes some way to easing my mind! Everything else is accounted for I think - the main bulk of the auto decomp that broke off and popped the hole in the rocker cover, part of the auto decomp left on the cam shaft, and some small shards/debris at the bottom of the casing. I didn't realise it could be run without the stop bolt, so hopefully that's the case here - there's definitely no sign of it.
I'll have a good look at that bearing. Both will now be replaced anyway I guess, along with new auto decomp + chain.
Cheers.

 

[Taffy]

7 Ned! you might have lost a pair of balls though!

7 balls in the cam bearings.

LOL!!!

Taffy

 

[ned37]

i knew it was an odd number, taf. i'm lucky that i can still remember that much.
never hurts to have extra balls!

 

[BLUDGEONER]

Quick update - though nothing has really happened yet! Work/holidays/general stuff has got in the way of things lately. Just now got around to getting the engine out, so will now try to find the time (and space on a bench) to have a go at this.
All 7 balls are present in the bearing, and no traces of shredded seal, so looks like someone HAS replaced it with an open bearing. With that in mind - and the fact that the stop bolt is (seems to be) completely absent - what would have caused the auto decomp to break up?

 

[BLUDGEONER]

Update - Finally getting around to sorting this broken decomp issue. I will be putting the stop bolt back in!! Seems this engine has had some work -
Has HCDI No. 15 on the camshaft, which I believe is a stage 2 Hotcam for a KTM RFS (with the end of the shaft cut off).

Looks like a high comp piston - no markings visible to check -

Some porting has been done, though not visible in this pic due to the black crud build up - normal or excessive??

Hopefully get this back together and running soon....

 

[FE350]

RFS 520 EXC Hot Cam Stage 2

 

[bushmechanic]

What is the exhaust valve to piston clearance ?
Might be good to check it with clay as the Piston looks a bit odd and we don't know if that happened earlier when the valve timing was out or not